Implant manufacturing method

Abstract

To provide a method for manufacturing an implant having a completely different shape from conventional methods, in which the shape of the implant is adapted to each site where it is to be embedded. [Solution] This is a method for manufacturing an implant (100) used in place of a maxillary molar, which is formed by integrating three separate root equivalent portions (121, 122, 123) with one crown prosthesis portion (150) connected to the base end of the root equivalent portions, and has an abutment (170) attached. One or two vertical grooves (135) having a predetermined depth are formed on the inner surface of each root equivalent portion, extending from the tip of the root toward the base end of the root over approximately one-third of the length of each root equivalent portion, and horizontal grooves (111, 112, 131) of a predetermined depth are formed in a row at predetermined intervals on the surface area of ​​each root equivalent portion, from the underside of the cervical equivalent area formed on the abutment attachment side of the crown prosthesis toward the root tip of each root equivalent portion.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an implant, which is becoming increasingly popular in the field of dentistry. [Background technology]

[0002] In recent years, implants have become widely used in the field of dentistry due to the advent of an aging society, as they help maintain chewing ability and eliminate the hassle of daily cleaning and maintenance associated with removing dentures.

[0003] The basic structure of such an implant consists of a fixture, which is a rod-shaped body with a male thread formed around it, and an abutment that is screwed onto the upper end of the root of the tooth and fixed in place.This is embedded in a hole drilled into the jawbone in the area where the root has been removed, and a crown is then attached to serve as an artificial tooth on top of the implant (see, for example, Patent Document 1). [Patent Document 1] Japanese Patent Application Publication No. 8-019555 Summary of the Invention [Problem to be solved by the invention]

[0004] Before explaining the problem to be solved by the present invention, the physiological structure and characteristics of teeth, which play an important role in chewing and swallowing food, and the jawbone that supports them, which are directly related to the problem to be solved by the present invention, will be explained below.

[0005] An adult has 16 permanent teeth (including third molars, or "wisdom teeth") in each of the upper and lower jaws. These 16 teeth are arranged symmetrically on each side: two incisors, one canine, two premolars, and three molars. The following features are relevant to the problem to be solved by this invention: (a) The force generated during bite is extremely large. For adults, although this varies depending on age, sex, and build, it is generally equivalent to the person's weight (50 kg (approximately 500 N) to 70 kg (approximately 700 N) per 1 cm2, and in strong bite forces, it can reach as much as 100 kg (approximately 1000 N). When biting, the upper and lower teeth overlap for an instant, so the impact force (impulse) F × Δt generated at that time is also quite large. In addition, this biting action is repeated many times during each meal, so when the bite forces acting on the teeth during one meal are integrated, it acts as an extremely large impulse. (b) Chewing various types of food requires more than simply moving the upper and lower teeth up and down. For example, chewing soft, medium-hard meat, fish, or vegetables into small pieces, or chewing hard meat, fish, cartilage rich in calcium and collagen, or nuts, requires complex movements of the upper and lower teeth. Specifically, chewing requires unconscious, sequential, or simultaneous complex movements, such as a biting action to bite off food, a crushing action to crush the chewed food, and a grinding action to grind the chewed food. In other words, the teeth on the upper and lower jaws repeat a complex combination of biting, crushing, and grinding movements, and therefore are not limited to a simple uniaxial movement in the up-and-down direction, but rather repeat movements in the up-and-down, left-and-right, front-and-back directions, as well as three-dimensional directions that include the rotation of the upper and lower teeth while they are in occlusion, which is associated with grinding movements, and extremely complex three-dimensional combined movements. (c) The upper side of the maxilla is home to a cavity called the maxillary sinus, while the lower jaw is home to nerves, arteries, and veins beneath the tooth roots, and the chewing muscles generate the very large bite force described above to crush food. Due to these physiological actions, combined with the biological tissue structure around the jawbone, the bone density of the upper jaw is relatively sparse, while the bone density of the lower jaw is denser. Therefore, the first molars on the left and right of the maxilla each have a trifurcate root (the second premolar has a bifurcate root), and are firmly rooted in the upper jaw, where the bone density is relatively sparse, while the first and second molars on the left and right of the mandible each have a bifurcate root, and are firmly rooted in the lower jaw, where the bone density is relatively dense.

[0006] Incidentally, currently commonly used implants consist of a single, elongated rod-shaped body, as mentioned above, and are inserted into the upper or lower jaw, leaving a portion undisturbed.

[0007] Current implants are basically long, thin rod-shaped bodies with a circular cross section, so when occlusal force perpendicular to the longitudinal direction of the implant, which occurs when chewing food due to the grinding movement of the upper and lower teeth during bite, is applied to the crown, a moment is generated at the part of the implant inserted into the jawbone, and this occlusal force causes a point contact between one point on the circumferential surface of the implant and the corresponding part of the jawbone, applying a large local force to this part, causing stress to concentrate in this local part of the jawbone and inducing local destruction of the jawbone.

[0008] In addition to the excessive impact (a) that occurs with each bite movement during eating, if a three-dimensional vector bite force (b) is applied to the top of the crown attached to the implant, an excessive bending moment will be generated at the tip of the implant.

[0009] Repeated attempts to do this can damage the interface between the implant and the jawbone, eventually destroying the entire jawbone along this interface, causing the implant itself to become loose. This can also allow bacteria such as fungi and viruses to enter the gaps that form along this interface from the oral cavity, causing peri-implantitis.

[0010] In particular, the upper jaw has a low bone density as mentioned above (c), so if you bite down hard on food every time you eat after having an implant placed in the upper jaw, the above problems are more likely to occur.

[0011] Similarly, even if implants are placed in the lower jaw, implant users will experience that they no longer experience severe pain in their teeth or have their dentures come loose, even when they bite down hard when eating, and as they continue to use the implants, they will become accustomed to chewing with a relatively strong bite force.In other words, they will learn the comfort of swallowing food after chewing it thoroughly, and as a result, their bite force will increase, which could eventually lead to the same problems as those mentioned above.

[0012] If this problem occurs, the implant in the lower jaw will eventually become loose and unusable, just as it was in the upper jaw. In this case, the implant will have to be removed and replaced with a new one, meaning that a hole will have to be re-drilled in the same place where the first implant was removed and a second implant will be inserted.

[0013] However, as mentioned above (c), the lower jaw has arteries and nerves running around the underside of the tooth root, so there is a concern that when a second implant is inserted, bleeding may not stop or the nerves may be damaged, leading to serious problems such as numbness in the lower jaw.

[0014] In addition, even if the serious problems mentioned above do not occur when using current implants, the following inconveniences arise: Specifically, after extracting and completely removing the loosened tooth root, it may be necessary to suture the gums and wait for about six months for the bone to grow around the extracted area and close it, until a hole for the implant can be drilled.

[0015] During this time, the tooth in this area is completely missing, which not only looks bad and is self-conscious and psychologically undesirable, but also causes food to get caught in the toothless area when biting, forcing the patient to use their tongue to remove it each time, making it difficult to enjoy eating.

[0016] Furthermore, even if the bone around the extracted tooth is allowed to grow, and a current implant is inserted and a crown is attached via an abutment, aesthetic problems remain. The reason for this is that current implants are basically made by rotating and cutting a rod-shaped body using an NC lathe, etc., and then processing it to form a male thread for implantation and retention.

[0017] With this processing method, the part of the tip of the implant that protrudes from the gum where the abutment is attached ends up being the same height both inside and outside the oral cavity, that is, when viewed from the lip side and the tongue side.As a result, even if a crown is attached via the abutment, the gums will eventually recede, leaving a part of the metal part of the abutment exposed between the crown and the gums below.When opening your mouth to talk, this metal part becomes visible from the outside, making it immediately obvious that an implant has been inserted, which is problematic from an aesthetic point of view.

[0018] The object of the present invention is to solve the problems associated with conventional implants, which have a basic rod-like shape with a circular cross section, and to provide a manufacturing method for an implant with a completely different form from conventional ones, in which the shape of the implant is tailored to the site where it is to be implanted, taking into account the characteristics of the bite force to be applied, in order to quickly implant the implant and maintain durability against large bite forces for a long period of time after implantation. [Means for solving the problem]

[0019] In order to solve the above-mentioned problems, the method for producing an implant according to claim 1 of the present invention comprises: 1. A method for manufacturing an implant to replace a maxillary molar, comprising: The dental prosthesis is formed by joining three separate root-equivalent portions together at the base end of the three root-equivalent portions, and forming a single crown prosthesis. An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over approximately one-third of the length of each tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to the root tip of each of the root equivalent regions in a surface region excluding the surface region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent region, The implant-compatible 3D information, which represents the size and shape of the integrated root and crown prosthesis of the natural tooth that will be used to place the implant in the jawbone, is obtained as 3D data through a CT scan. Based on the implant-compatible three-dimensional information obtained as this 3D data, an implant is manufactured using a 3D printer so that each region of the implant surface has a different surface roughness. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0020] The method for producing an implant according to claim 2 of the present invention comprises the steps of: 1. A method for manufacturing an implant to replace a maxillary molar, comprising: The dental prosthesis is formed by joining three separate root-equivalent portions together at the base end of the three root-equivalent portions, and forming a single crown prosthesis. An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over approximately one-third of the length of each tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to the root tip of each of the root equivalent regions in a surface region excluding the surface region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent region, The implant-compatible 3D information, which represents the size and shape of the integrated root of the natural tooth that will be the base for the implant in the jawbone, the crown prosthesis, and the abutment, is obtained as 3D data through a CT scan. Based on the implant-compatible 3D information obtained as 3D data, a temporary model of the individual implant shape is manufactured using a 3D printer using wax material with a wax pattern that is the same shape as the natural tooth. This temporary model of individual shape is used to first embed the tooth in a coarse-grained embedding agent to form a rough surface over approximately two-thirds of the area from the tip of the root equivalent portion to the lower side of the cervical portion formed in the crown prosthesis portion, Secondary investment is made with finer investment material so that the surface of the entire crown prosthesis above the remaining cervical part of the temporary model becomes smooth. After hardening all of these investments, they are heated together to burn off all of the wax that made up the temporary model. The metal that will become the implant material is poured into the implant, and an implant with the same shape as the temporary model is cast before some of the surface is polished. Regarding the cervical preparation area, the surface of this area is further polished to make it smoother, thereby producing an implant with different surface roughness in each area of ​​the implant surface. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0021] The method for producing an implant according to claim 3 of the present invention comprises the steps of: 1. A method for manufacturing an implant to replace a maxillary molar, comprising: The dental prosthesis is formed by joining three separate root-equivalent portions together at the base end of the three root-equivalent portions, and forming a single crown prosthesis. An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over approximately one-third of the length of each tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to the root tip of each of the root equivalent regions in a surface region excluding the surface region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent region, The implant-compatible 3D information, which represents the size and shape of the integrated root of the natural tooth that will be the base for the implant in the jawbone, the crown prosthesis, and the abutment, is obtained as 3D data through a CT scan. Based on the implant-compatible 3D information obtained as 3D data, a temporary model of the individual implant shape is manufactured using a 3D printer using wax material with a wax pattern that is the same shape as the natural tooth. The entire temporary model is embedded in an investment material used in the lost wax method, and then the entire investment material is hardened and heated to burn off the wax that constitutes the temporary model. Molten implant material is poured into the implant to create a smooth implant with an entire surface. The entire surface of the implant is smooth, and approximately two-thirds of the area from the tip of the root-equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis is surface-treated using a sandblasting method to have a rough surface roughness. At the same time, the area from the rough surface roughness to the lower side of the cervical portion is surface-treated to have a fine surface roughness. Regarding the region where the tooth neck is formed, the surface up to the lower side of this region is further polished to make it smoother, thereby manufacturing an implant with different surface roughness in each region of the implant surface. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0022] The method for producing an implant according to claim 4 of the present invention comprises the steps of: A method for manufacturing an implant to replace a premolar in the upper jaw or a molar in the lower jaw, comprising: The two separate tooth root equivalents and the proximal end of the two tooth root equivalents are joined together to form a single crown prosthesis, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of each tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to the root tip of each of the root equivalent regions in a surface region excluding the surface region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent region, The implant-compatible 3D information, which represents the size and shape of the integrated root and crown prosthesis of the natural tooth that will be used to place the implant in the jawbone, is obtained as 3D data through a CT scan. Based on the implant-compatible three-dimensional information obtained as this 3D data, an implant is manufactured using a 3D printer so that each region of the implant surface has a different surface roughness. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0023] The method for producing an implant according to claim 5 of the present invention comprises the steps of: A method for manufacturing an implant to replace a premolar in the upper jaw or a molar in the lower jaw, comprising: The two separate tooth root equivalents and the proximal end of the two tooth root equivalents are joined together to form a single crown prosthesis, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of each tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to the root tip of each of the root equivalent regions in a surface region excluding the surface region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent region, The implant-compatible 3D information, which represents the size and shape of the integrated root of the natural tooth that will be the base for the implant in the jawbone, the crown prosthesis, and the abutment, is obtained as 3D data through a CT scan. Based on the implant-compatible 3D information obtained as 3D data, a temporary model of the individual implant shape is manufactured using a 3D printer using wax material with a wax pattern that is the same shape as the natural tooth. This temporary model of individual shape is used to first embed the tooth in a coarse-grained embedding agent to form a rough surface over approximately two-thirds of the area from the tip of the root equivalent portion to the lower side of the cervical portion formed in the crown prosthesis portion, Secondary investment is made with finer investment material so that the surface of the entire crown prosthesis above the remaining cervical part of the temporary model becomes smooth. After hardening all of these investments, they are heated together to burn off all of the wax that made up the temporary model. The metal that will become the implant material is poured into the implant, and an implant with the same shape as the temporary model is cast before some of the surface is polished. Regarding the cervical preparation area, the surface of this area is further polished to make it smoother, thereby producing an implant with different surface roughness in each area of ​​the implant surface. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0024] The method for producing an implant according to claim 6 of the present invention comprises the steps of: A method for manufacturing an implant to replace a premolar in the upper jaw or a molar in the lower jaw, comprising: The two separate tooth root equivalents and the proximal end of the two tooth root equivalents are joined together to form a single crown prosthesis, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of each tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to the root tip of each of the root equivalent regions in a surface region excluding the surface region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent region, The implant-compatible 3D information, which represents the size and shape of the integrated root of the natural tooth that will be the base for the implant in the jawbone, the crown prosthesis, and the abutment, is obtained as 3D data through a CT scan. Based on the implant-compatible 3D information obtained as 3D data, a temporary model of the individual implant shape is manufactured using a 3D printer using wax material with a wax pattern that is the same shape as the natural tooth. The entire temporary model is embedded in an investment material used in the lost wax method, and then the entire investment material is hardened and heated to burn off the wax that constitutes the temporary model. Molten implant material is poured into the implant to create a smooth implant with an entire surface. The entire surface of the implant is smooth, and approximately two-thirds of the area from the tip of the root-equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis is surface-treated using a sandblasting method to have a rough surface roughness. At the same time, the area from the rough surface roughness to the lower side of the cervical portion is surface-treated to have a fine surface roughness. Regarding the region where the tooth neck is formed, the surface up to the lower side of this region is further polished to make it smoother, thereby manufacturing an implant with different surface roughness in each region of the implant surface. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0025] Furthermore, a method for producing an implant according to claim 7 of the present invention comprises the steps of: This is a manufacturing method for implants used to replace upper front teeth and canines, or lower front teeth, canines, and premolars. A single tooth root equivalent and a crown prosthesis formed in connection with the base end of the single tooth root equivalent are integrally formed, An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the lingual side of the posterior surface of the tooth root equivalent portion, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity to the tooth root base end side in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of the tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to a tip of the root of the tooth corresponding portion in a surface region excluding the surface region that is a region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent portion, The implant-compatible 3D information, which represents the size and shape of the integrated root and crown prosthesis of the natural tooth that will be used to place the implant in the jawbone, is obtained as 3D data through a CT scan. Based on the implant-compatible three-dimensional information obtained as this 3D data, an implant is manufactured using a 3D printer so that each region of the implant surface has a different surface roughness. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0026] Furthermore, the method for producing an implant according to claim 8 of the present invention comprises the steps of: This is a manufacturing method for implants used to replace upper front teeth and canines, or lower front teeth, canines, and premolars. A single tooth root equivalent and a crown prosthesis formed in connection with the base end of the single tooth root equivalent are integrally formed, An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the lingual side of the posterior surface of the tooth root equivalent portion, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity to the tooth root base end side in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of the tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to a tip of the root of the tooth corresponding portion in a surface region excluding the surface region that is a region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent portion, The implant-compatible 3D information, which represents the size and shape of the integrated root of the natural tooth that will be the base for the implant in the jawbone, the crown prosthesis, and the abutment, is obtained as 3D data through a CT scan. Based on the implant-compatible 3D information obtained as 3D data, a temporary model of the individual implant shape is manufactured using a 3D printer using wax material with a wax pattern that is the same shape as the natural tooth. This temporary model of individual shape is used to first embed the tooth in a coarse-grained embedding agent to form a rough surface over approximately two-thirds of the area from the tip of the root equivalent portion to the lower side of the cervical portion formed in the crown prosthesis portion, Secondary investment is made with finer investment material so that the surface of the entire crown prosthesis above the remaining cervical part of the temporary model becomes smooth. After hardening all of these investments, they are heated together to burn off all of the wax that made up the temporary model. The metal that will become the implant material is poured into the implant, and an implant with the same shape as the temporary model is cast before some of the surface is polished. Regarding the cervical preparation area, the surface of this area is further polished to make it smoother, thereby producing an implant with different surface roughness in each area of ​​the implant surface. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0027] Furthermore, a method for producing an implant according to claim 9 of the present invention comprises the steps of: This is a manufacturing method for implants used to replace upper front teeth and canines, or lower front teeth, canines, and premolars. A single tooth root equivalent and a crown prosthesis formed in connection with the base end of the single tooth root equivalent are integrally formed, An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the lingual side of the posterior surface of the tooth root equivalent portion, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity to the tooth root base end side in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of the tooth root equivalent portion, and a method for manufacturing an implant in such a way that horizontal grooves of a predetermined depth are formed in a row at predetermined intervals from below the cervical equivalent region to a tip of the root of the tooth corresponding portion in a surface region excluding the surface region that is a region below the cervical equivalent region of the crown prosthesis and the vertical groove formation region of the root equivalent portion, The implant-compatible 3D information, which represents the size and shape of the integrated root of the natural tooth that will be the base for the implant in the jawbone, the crown prosthesis, and the abutment, is obtained as 3D data through a CT scan. Based on the implant-compatible 3D information obtained as 3D data, a temporary model of the individual implant shape is manufactured using a 3D printer using wax material with a wax pattern that is the same shape as the natural tooth. The entire temporary model is embedded in an investment material used in the lost wax method, and then the entire investment material is hardened and heated to burn off the wax that constitutes the temporary model. Molten implant material is poured into the implant to create a smooth implant with an entire surface. The entire surface of the implant is smooth, and approximately two-thirds of the area from the tip of the root-equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis is surface-treated using a sandblasting method to have a rough surface roughness. At the same time, the area from the rough surface roughness to the lower side of the cervical portion is surface-treated to have a fine surface roughness. Regarding the region where the tooth neck is formed, the surface up to the lower side of this region is further polished to make it smoother, thereby manufacturing an implant with different surface roughness in each region of the implant surface. A method for manufacturing an implant, comprising: The implant is manufactured so that, of the entire surface area from the root tip of the tooth root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the tooth root equivalent part to the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness. It is characterized by the following.

[0028] Furthermore, a method for producing an implant according to claim 10 of the present invention is a method for producing an implant according to any one of claims 7 to 9, The aforementioned A predetermined inclined area is further provided on the labial surface of the crown prosthesis, which is attached to the cervical part of the crown prosthesis, and is angled so as to approach the root-equivalent part from the center toward the peripheral edge of the labial side. the peripheral edge The implant is manufactured so as to be formed as follows. [Effects of the Invention]

[0031] According to the present invention, the problems associated with conventional implants, which have a basic rod-like shape with a circular cross section, are resolved, and a manufacturing method for an implant with a completely different form from conventional methods can be provided, in which the shape of the implant is adapted to the site where it is to be embedded, taking into account the characteristics of the occlusal force to be applied, in order to enable rapid implantation and to maintain durability against large occlusal forces for a long period of time after implantation. [Brief explanation of the drawings]

[0032] [Figure 1] 1A is a schematic perspective view showing an implant according to a first embodiment of the present invention with a dental crown placed on its abutment (FIG. 1A), and a partial cross-sectional view thereof (FIG. 1B). [Figure 2] 2(a) is a cross-sectional view showing the state of the implant shown in FIG. 1 immediately after it has been actually embedded in the implant embedding site in the maxilla, cut in a direction perpendicular to the extension direction of the root-equivalent portion, and FIG. 2(b) is a partial cross-sectional view cut along the central axis in the direction in which one root-equivalent portion extends. [Figure 3] 3(a) is a cross-sectional view showing the state after bone has grown from the state shown in FIG. 2 and the implant has been completely embedded, and FIG. 3(b) is a partial cross-sectional view cut along the central axis in the direction in which one tooth root equivalent extends. [Figure 4]4(a-1) is a schematic perspective view showing an implant according to a second embodiment of the present invention with a crown placed on its abutment, as viewed from the labial side, and FIG. 4(a-2) is a cross-sectional view taken along a line perpendicular to the direction of extension of the root-equivalent portion; and FIG. 4(b-1) is a schematic perspective view showing an implant according to the second embodiment with a crown placed on its abutment, as viewed from the lingual side, and FIG. 4(b-2) is a cross-sectional view taken along a line perpendicular to the direction of extension of the root-equivalent portion. [Figure 5] 5(1) is a perspective view of an implant for a front tooth or canine tooth of the upper jaw, or a front tooth, canine tooth, or premolar tooth of the lower jaw according to a third embodiment of the present invention, as viewed from the lingual side with a crown placed on its abutment; FIG. 5(1-a) is a cross-sectional view of a portion not including a longitudinal groove formed along the extension direction of a tooth root equivalent, cut in a direction perpendicular to the extension direction of the tooth root equivalent; FIG. 5(1-b) is a cross-sectional view of a portion including a longitudinal groove formed along the extension direction of a tooth root equivalent, cut in a direction perpendicular to the extension direction of the tooth root equivalent; 5(2) is a perspective view seen from the lingual side with a crown placed on it; FIG. 5(2-c) is a cross-sectional view of a portion not including the longitudinal groove formed along the extending direction of the root equivalent portion, cut perpendicular to the extending direction of the root equivalent portion; FIG. 5(2-d) is a cross-sectional view of a portion including the longitudinal groove formed along the extending direction of the root equivalent portion, cut perpendicular to the extending direction of the root equivalent portion; and FIG. 5(3) is a perspective view showing a partial cross-section of a portion along the longitudinal groove formed in the root equivalent portion with a crown placed on the abutment of an implant for a maxillary anterior tooth or canine, or a mandibular anterior tooth, canine, or premolar according to a third embodiment of the present invention. [Figure 6]FIG. 6(a-1) is an oblique view showing a partial cross section of the longitudinal groove of an implant according to a modified example of the third embodiment of the present invention, with the lip side on the left and the tongue side on the right; a first explanatory diagram (FIG. 6(a-2)) showing the action and effect of the implant according to the modified example shown in FIG. 6(a-1); a second explanatory diagram (FIG. 6(a-3)) showing the action and effect of the implant according to the modified example shown in FIG. 6(a-1); a perspective view (FIG. 6(b-1)) of a conventional implant; a first explanatory diagram (FIG. 6(b-2)) explaining the drawbacks of the conventional implant shown in FIG. 6(b-1); and a second explanatory diagram (FIG. 6(b-3)) explaining the drawbacks of the conventional implant shown in FIG. 6(b-1). DETAILED DESCRIPTION OF THE INVENTION

[0033] An embodiment (hereinafter referred to as "the present embodiment") as an example for carrying out the present invention will be described in detail below with reference to the drawings. It should be emphasized that the present invention is not limited to this embodiment, and various shapes, dimensions, materials, and the like for specifying the present invention can be applied to the present invention within the scope in which the effects of the present invention can be achieved. Furthermore, some drawings show the interior of a part of the configuration transparently. While these transparently shown parts should normally be drawn using dotted lines or two-dot chain lines, they are shown using solid lines for ease of understanding the invention and for convenience of explanation.

[0034] In addition, in each drawing, the jawbone 80 (see Figures 2 and 3) is shown on the bottom side with the implant placed from above, but it should be noted that in a configuration limited to inserting an implant into the upper jaw, such as the first embodiment, the drawing must be turned upside down to understand the configuration.

[0035] First, a first embodiment of the present invention will be described with reference to the drawings. Figure 1 shows a schematic perspective view (Figure 1(a)) and a partial cross-sectional view (Figure 1(b)) of an implant 100 according to the first embodiment of the present invention, with a crown 10 placed on its abutment 170.

[0036] An implant 100 according to a first embodiment of the present invention (hereinafter referred to as "this implant 100" or simply "implant 100") is an implant 100 used in place of a molar in the upper jaw. This implant 100 is composed of three separate root-equivalent portions 110, 120, and 130, and a single crown prosthetic portion 150 located at the base end of the three root-equivalent portions, where these root-equivalent portions 110, 120, and 130 are joined together.

[0037] An abutment 170, shown transparently in the drawing, is attached to the end of the crown prosthesis 150 opposite the root equivalents 110, 120, 130. On the inner surfaces of the opposing root equivalents 110, 120, 130, one or two (two in this embodiment) longitudinal grooves 115, 125, 135 having a predetermined depth are formed in the surface region from the root tip side (lower end side in FIG. 1(a)) to the root base side (upper end side in FIG. 1(a)), starting from the root tip or its vicinity and extending over approximately one-third of the length of each root equivalent 110, 120, 130.

[0038] Furthermore, in the surface region excluding the surface region below the cervical equivalent region 155 of the crown prosthesis 150 and the predetermined regions where the longitudinal grooves 115, 125, 135 of each of the root equivalent portions 110, 120, 130 are formed, lateral grooves 111, 121, 131 of predetermined depths are formed in a row at predetermined intervals from the lower side of the cervical equivalent region 155 to the root tips of each of the root equivalent portions 110, 120, 130. In this embodiment, seven lateral grooves 111, 121, 131 are formed at predetermined intervals from one another, but the present invention is not limited to this number.

[0039] Furthermore, in the implant 100 according to this embodiment, of the surface region R-1 extending from the lower end of the root equivalent portions 110, 120, 130 to the underside of the cervical equivalent region 155 of the crown prosthesis portion 150, approximately two-thirds of the surface region extending from the lower end of the root equivalent portions 110, 120, 130 toward the cervical equivalent region 155 of the crown prosthesis portion 150 (see region Ra-1 in Figure 1(a)) is formed with a rough surface roughness, while the remaining approximately one-third of the surface region extending to the underside of the cervical equivalent region 155 (see region Rb-1 in Figure 1(a)) is formed with a fine surface roughness.

[0040] The above-mentioned abutments may be created using the 3D printer introduced in the present invention in this embodiment and in each of the embodiments and their modified examples described below. Alternatively, it is also possible to prepare abutments of several different shapes and sizes as separate bodies in advance, and select an abutment 170 that is perfectly suited to each implant created using the 3D printer and attach it to the top of the crown prosthetic portion 150 of the implant 100.

[0041] Furthermore, when attaching the abutment 170 to the crown prosthesis part 150, a female screw may be formed in advance in the crown prosthesis part 150, and a male screw provided on the abutment 170 may be detachably screwed into it, or alternatively, a hole for attaching the abutment may be drilled in the crown prosthesis part 150, and an attachment protrusion provided on the abutment may be inserted into this hole, and the two may be firmly fixed together using cement or the like.

[0042] Here, when the crown prosthesis part 150 and the abutment 170 are connected by fastening a screw, they become detachable from each other, but on the other hand, when the two are connected using cement or the like, they basically become one body once connected. Therefore, in the explanations of this embodiment and the following embodiments and modifications, the crown prosthesis part 150 and the abutment 170 are connected by fastening a screw, and thus the two are detachable from each other.

[0043] Next, the surface roughness of the surface treatment, which is a characteristic feature of this first embodiment, the width and depth of the lateral grooves 111, 121, and 131, and the length, width, and depth of the longitudinal grooves 115, 125, and 135 will be described by way of example. In the first embodiment, the surface roughness of the rough surface region R-1a is, for example, an irregularity with a depth of about 50 nanometers (nm). On the other hand, the surface roughness of the fine surface region R-1b is an irregularity with a depth of about 10 nanometers (nm).

[0044] It should be noted that the numerical values ​​of the surface roughness are merely examples, and any numerical values ​​that produce the effects described in the present invention are applicable, and the present invention is not limited to these values. Furthermore, the above-mentioned example of numerical values ​​also applies to the second embodiment, the third embodiment, and the modified example of the third embodiment, and therefore the following description of these embodiments and their modified examples will be omitted by utilizing this description.

[0045] In the first embodiment, if the diameter of the crown prosthesis 150 shown in Fig. 1 is approximately 8 mm to 10 mm, the width of the lateral grooves 111, 121, and 131 shown in Fig. 1 in this case is, for example, approximately 1 mm and a depth of approximately 0.5 mm. In addition, the length of the longitudinal grooves 115, 125, and 135 in the first embodiment shown in Fig. 1 is, for example, approximately 5 mm, the width of the longitudinal grooves 115, 125, and 135 is, for example, approximately 1 mm to 0.5 mm, and a depth of approximately 0.5 mm.

[0046] The implant 100 according to this embodiment is made of titanium or a titanium alloy, which has excellent biocompatibility, but may also be made of other materials such as zirconium or zirconia (zirconium oxide). Alternatively, the implant may be made of a resin material such as PEEK (polyether ether ketone) or a carbon-reinforced polymer, which has excellent biocompatibility, strength, and ease of fabrication using a 3D printer.

[0047] Furthermore, the manufacturing of the implant 100 according to this embodiment involves the following manufacturing process, which is completely different from the conventional manufacturing process of cutting a single rod-shaped body. Specifically, implant-compatible three-dimensional information representing the size and shape of the integrated root and crown prosthesis as the original natural tooth corresponding to the site where the implant 100 is to be embedded in the jawbone (see FIGS. 2 and 3) is obtained as 3D data by CT scanning, and the desired implant 100 is formed using a 3D printer based on this implant-compatible three-dimensional information obtained as 3D data.

[0048] The method for manufacturing an implant according to this embodiment is common to all methods for manufacturing implants according to the present invention, and therefore this method for manufacturing an implant according to the second embodiment, the third embodiment, and a modified version of the third embodiment, which will be described later, is also applicable to the manufacture of the implant.

[0049] Below, we will explain an example of how to use a 3D printer to manufacture an implant 100 made from a titanium alloy. This manufacturing process is carried out based on information from a CT scan that captures a three-dimensional image of the natural tooth before it is replaced with the implant 100. In this process, first, titanium alloy powder that meets medical biocompatibility is prepared, and the desired implant 100 is created using selective laser sintering (SLS) or electron beam melting (EBM).

[0050] This allows individual production of implants 100 relating to the first embodiment, which have vertical grooves 115, 125, 135 of a predetermined depth extending a certain length from the tips of the tooth root equivalent portions 110, 120, 130, which are unique to the present invention, and horizontal grooves 111, 121, 131 of a predetermined depth at predetermined intervals from the underside of the tooth neck equivalent region 155 (see dotted line 155a in the figure) to the tips of the tooth root equivalent portions 110, 120, 130, and which have a desired surface roughness applied to a predetermined surface region R-1.

[0051] In addition, in order to maintain long-term durability against the above-mentioned excessive occlusal forces that are applied with each bite action that is repeated tens of thousands to hundreds of thousands of times each time a meal is eaten after implantation, it is considered preferable in the present invention to perform densification treatment or strength improvement treatment on the implant itself as needed during or at the final stage of the manufacturing process.

[0052] Specifically, after heat treatment such as HIP treatment is performed to improve the mechanical strength, surface treatment such as sandblasting is performed so that the surface of the implant 100 has the specific surface roughness according to the present invention. In this way, implants 100 are individually manufactured that have the same shape as the natural tooth before being replaced with implant 100 and have the specific longitudinal grooves 115, 125, 135, lateral grooves 111, 121, 131, and surface roughness according to the present invention.

[0053] Furthermore, when manufacturing implants using a 3D printer with highly biocompatible metals such as titanium, titanium alloys, zirconium, and zirconia, after creating the implant through the process described above, it is considered preferable to consider manufacturing higher quality individual implants by further heat treating or densifying the entire implant, taking into consideration the site where the implant will be placed and the large occlusal forces that will act on the implant over the long term, and to carry out these treatments as necessary.

[0054] Specifically, the details are as follows: Improvements in mechanical strength are as follows: After titanium or titanium alloys are created using a 3D printer, they are subjected to heat treatment (solution treatment, aging treatment, etc.) to remove any microscopic defects or stress remaining inside. This improves the strength and durability of the implant.

[0055] Densification processes include sintering and diffusion bonding, especially when using electron beam deposition or selective laser manufacturing (SLM), to ensure the proper density of the metallurgical structure after implant formation.

[0056] In this way, we believe it would be preferable to consider selectively carrying out sintering processes, other heat treatment processes, and densification processes as appropriate to improve the final product quality after the implant has been formed using a 3D printer.

[0057] A number of unique functions and effects of the implant 100 according to the first embodiment of the present invention will be described below. First, the first unique function and effect will be described. FIG. 2 is a cross-sectional view (FIG. 2(a)) showing the state of the implant 100 shown in FIG. 1 immediately after it has been actually embedded in an implant embedding site in the maxilla, cut in a direction perpendicular to the extension direction of the tooth root equivalents 110, 120, and 130, and a partial cross-sectional view (FIG. 2(b)) showing the state of the implant 100 cut along the central axis in the direction in which one of the tooth root equivalents 110, 120, and 130 extends. Furthermore, FIG. 3 is a cross-sectional view (FIG. 3(a)) showing the state of the implant 100 after bone growth from the state shown in FIG. 2 has completely embedded, and a partial cross-sectional view (FIG. 3(b)) showing the state of the implant 100 cut along the central axis in the direction in which one of the tooth root equivalents 110, 120, and 130 extends.

[0058] According to the present invention, in the process from Figure 2 to Figure 3, in Figure 2, the gap between the jawbone 80 and the implant 100 immediately after the original natural tooth that has become loose and is no longer performing its original function has been extracted and the necessary treatment has been performed, i.e., the gap that is slightly thicker than the thickness of the periodontal ligament around the tooth root equivalents 110, 120, 130, as well as the narrow space formed by the lateral grooves 111, 121, 131 and the longitudinal grooves 115, 125, 135 of the implant 100, are left as blank spaces in the drawing. On the other hand, in Figure 3, it can be visually understood from the absence of blank spaces in the drawing that the gaps and spaces shown in Figure 2 have been filled in a short time by bone growth, and the jawbone 80 and the implant 100 have been completely joined.

[0059] Let's compare this to the process of placing a conventional implant. With conventional implants, after the original natural tooth that no longer functions properly is extracted, the gum area is sutured and the entire natural tooth is left missing for about six months. During this process, the natural tooth that formed in the jawbone after the extraction and the surrounding periodontal ligament are removed, and the large space created in its place is filled with a jawbone growth promoter or similar.

[0060] This requires a complex procedure in which the surrounding bone grows and fills the space, then the sutured area is re-incised, a hole is drilled into the jawbone with an implant drill, and the implant is then screwed in.

[0061] However, as is clear from the above description of the structure of the implant 100 according to this embodiment, the present invention does not require a series of complicated operations or procedures as in the case of conventional implant embedding.

[0062] In other words, as is clear when compared with this conventional method, by using the implant 100 according to the present invention, it can be understood that the present invention makes it possible to quickly and securely embed the implant 100 without the inconvenience of food fragments getting caught or stuck during meals, which occurs when the tooth is left missing for a long period of time after extraction, and without the need for work or procedures that place a considerable physical burden on the implant recipient, such as drilling a hole in the jawbone with a drill or the like, after the jawbone has fully grown to close the space left after the tooth extraction.

[0063] In addition, according to the present invention, as explained in the first embodiment, large spaces remain after tooth extraction (the entire virtual space area inside the dotted circle in FIG. 2(a) and the entire virtual space area to the right of the dotted vertical line in FIG. 2(b)), and it is necessary to wait until the bone indicated by the small dots around this area grows and fills these spaces. Even if a bone growth material or the like is inserted, it is clear that a certain amount of time is required for the bone to grow to the point where a hole that serves as the base for implant placement can be drilled using a conventional implant placement drill used in dentistry.

[0064] However, as is clear from the diagrams showing the effects of this first embodiment, the present invention has the special advantage that the gap between the tooth root equivalent portions 110, 120, 130 of the implant 100 and the jawbone 80 is limited to a fairly narrow spatial area, making it possible to fill this narrow spatial area in a short period of time through bone growth.

[0065] This can be visually understood from the narrow margin between the dotted circle and the solid line portion in the vicinity of the dotted circle in Fig. 2(a) and the narrow margin between the dotted vertical line and the solid line portion in the vicinity of the right side in Fig. 2(b), which are spatial regions depicted as cases that actually occur in the first embodiment of the present invention. Note that the special advantages of the first embodiment described here can be said to be unique special advantages possessed by all of the second and third embodiments and their modifications, i.e., only by the present invention.

[0066] Next, a second unique effect of the implant 100 according to the first embodiment will be described. Of the surface region R-1 extending from the root-equivalent ends of the root-equivalent portions 110, 120, and 130 of the implant 100 according to the first embodiment to the lower side of the neck-equivalent region 155 occupying the upper side of the crown prosthesis 150, the surface roughness is formed roughly in the lower two-thirds of the surface region (see region Ra-1 in FIG. 1(a)) extending from the lower ends of the root-equivalent portions 110, 120, and 130 toward the neck-equivalent region 155 of the crown prosthesis 150, and the surface roughness is formed finely in the upper one-third of the surface region (see region Rb-1 in FIG. 1(a)) extending to the lower side of the neck-equivalent region 155.

[0067] First, the function of the area with a fine surface roughness will be described. After the implant 100 is placed, the area with a fine surface roughness is located close to the gums. This leaves almost no gap between the area with a fine surface roughness of the implant 100 and the surrounding jawbone 80 that is in close contact with it, greatly improving the degree of adhesion.

[0068] As a result, it becomes difficult for microorganisms such as fungi and bacteria to invade between the gums and the implant 100. Furthermore, since the degree of adhesion is extremely high between the surface region Rb-1 with the fine surface roughness and the jawbone 80 as described above, even if microorganisms invade the gums and the region corresponding to the tooth neck 155, the microorganisms such as fungi and bacteria are reliably prevented from invading deeper in the implant 100, that is, between the part of the surface region R-1 of the implant 100 with the rough surface roughness and the jawbone 80.

[0069] In this way, microorganisms such as fungi and bacteria can penetrate deep into the tooth root equivalent parts 110, 120, 130 of the implant 100, causing inflammation in these parts, thereby preventing the occurrence of implant peridontitis and reliably avoiding destruction of the interface between the implant 100 and the jawbone 80.

[0070] Structural destruction between the deep part of the implant and the jawbone 80 due to peri-implantitis induces implant mobility, which progresses irreversibly when occlusal forces are applied, eventually impairing the function of the implant itself, making it necessary to remove the implant again and replace it with a newer implant.

[0071] Therefore, when this happens, it imposes a physical and financial burden on the implant recipient. Furthermore, placing a second implant requires a larger scale of work, and depending on the original thickness and shape of the jawbone and the location of the nerves in the jawbone, it may not be possible to place a second implant, and the first implant may end up being wasted.

[0072] However, according to the present invention, for the reasons mentioned above, such extremely troublesome peri-implantitis can be prevented in advance, and therefore, once the implant 100 is placed, it has the unique effect of being able to continue to be used for a long period of time.

[0073] Furthermore, after the implant 100 is embedded, the region R-1a with a rough surface roughness penetrates further into the jawbone 80, which is further away from the gums than the region R-1b with a fine surface roughness, and becomes integrated with the jawbone. The rough surface roughness of the implant 100 naturally increases the surface area of ​​the implant 100 in this region, and as a result, the area of ​​contact with the jawbone 80 also increases. In this case, this portion becomes the base of the implant 100, and this increased contact area allows the base portion of the implant 100 to firmly contact the jawbone 80, making it possible to maintain a good embedded state of the implant 100 for a longer period of time.

[0074] Next, a third unique effect of the implant 100 according to the first embodiment will be described. As will be explained at the end of this specification, the bone density of the maxilla is denser than that of the mandible. This difference in bone density between the two is inevitable due to the structural and physiological reasons of the jawbone. Therefore, if the implant 100 is placed in place of a maxillary molar as in the past, various problems will arise.

[0075] Specifically, as explained in the section on problems to be solved by the invention, molars play an important role as the primary digestive organs, tightly gripping and shearing hard foods such as meat, firm vegetables, and nuts not only through the vertical bite of the upper and lower molars but also through a grinding motion known as a pestle action, before swallowing them.

[0076] Therefore, when conventional implants, which are basically rod-shaped components with a circular cross section, are implanted in the upper jaw, where bone density is low, it is like driving a stake into soil with poor foundations.Thus, although it is possible to implant a thicker implant in the molar area, which is deep in the jawbone, it is ultimately just a single rod-shaped implant driven in like a stake.

[0077] In this embodiment, under such circumstances where complex occlusal movements, including not only the above-mentioned up-and-down occlusal movements but also front-to-back and left-to-right grinding movements, are necessarily constantly occurring, occlusal forces act in three dimensions on the upper portion of the implant 100 embedded in the maxilla (the portion that is covered and fixed with the dental crown 10). As a result, moments in complex directions constantly act on the tip of the implant 100 relative to the side of the implant 100 embedded in the jawbone.

[0078] The problem here is that conventional implants placed in place of molars in the maxilla are basically rod-shaped members with circular cross sections, as mentioned above. Therefore, when occlusal force acts on the implant abutment in a direction that forms a certain angle with the direction in which the implant extends, an excessive pressing force based on the moment acting on the conventional implant acts between a small portion of the implant's circumferential surface and a small portion of the inner circumferential surface of the jawbone that is in close contact with it.

[0079] Due to the action of localized and concentrated components of excessive bite force on the maxilla, which has a high bone density, excessive pressing force from the conventional implant acts on localized parts of the jawbone 80 in a point contact rather than a surface contact. As a result, fine cracks occur in localized parts of the jawbone 80. Once a crack occurs, the application of similar force will cause the crack to grow, leading to the destruction of that part of the jawbone 80.

[0080] As mentioned above, molars are subjected to bite forces in various directions during grinding, which can cause damage to various parts of the maxilla that come into contact with the peri-implant surface, eventually causing the implant to become loose and making it impossible to continue using, which can lead to situations where the implant needs to be re-implanted.

[0081] However, the implant 100 used in place of a maxillary molar according to the present invention has root-equivalent portions 110, 120, and 130 that are trifurcated like natural teeth, so unlike the conventional example in which a single stake is driven into soil that has not yet solidified completely, the implant is in a state where the legs of a tripod are completely buried in the soil.

[0082] As a result, even if a force in a special direction associated with molar grinding acts on the crown prosthesis portion 150 of the implant 100, the remaining two tooth root equivalent portions 110, 120, 130, which are different from the tooth root equivalent portions 110, 120, 130 to which the occlusal force is applied, exert a repulsive force that braces the implant 100 to prevent it from falling over. This prevents a large force due to the occlusal force or the moment resulting therefrom from being applied to a localized portion of the joint region between the implant 100 and the jawbone 80. As a result, it is possible to prevent localized destruction of the jawbone 80 around the implant due to the local concentration of load caused by the moment generated by molar grinding, as in the conventional case.

[0083] Next, a fourth unique effect of the implant 100 according to the first embodiment will be described. For example, when trying to grind hard meat or sticky gummy candy by repeatedly shifting the upper and lower molars clockwise and counterclockwise around the axis of the molars while the upper and lower molars are in occlusion, a force is exerted that rotates the crown of the molar itself together with the abutment in a clockwise or counterclockwise direction. Therefore, with a conventional so-called general implant in which a male thread is formed around a rod-shaped body with a deformed cross section, the operation is like repeatedly tightening and loosening a screw, just like tightening and loosening a bolt.

[0084] As a result, when conventional implants are placed, loosening occurs between the implant and the upper jaw, which has a low bone density, particularly in the case of upper molars that are completely screwed into the upper jaw and integrated into it. Eventually, this loosening increases, and there is a risk that the part of the upper jaw that is connected to the implant will break down, as described above, causing the implant to become loose.

[0085] On the other hand, in this embodiment, the opposing inner surfaces of each of the root equivalent portions 110, 120, and 130 of the implant 100 are configured to have one or two (two in the drawing) vertical grooves 115, 125, and 135 having a predetermined depth extending from the root tip side (lower end side in Figure 1(a)) to the root base side (upper end side in Figure 1(a)), starting from the root tip side toward the root base side, over a length of approximately one-third of the length of each root equivalent portion 110, 120, and 130.

[0086] In this embodiment, the longitudinal grooves 115, 125, and 135 are formed at a distance quite close to the central axis of the implant 100, and thus the jawbone 80 penetrates and couples to the aforementioned locations of each of the tooth root-corresponding portions 110, 120, and 130 over the entire extension direction of the longitudinal grooves 115, 125, and 135. This provides the following unique advantages. Specifically, even if a force that repeatedly rotates the implant 100 around its axis in clockwise and counterclockwise directions due to the special grinding motion described above acts, the torsional moment around the axis of the implant 100 caused by this force can be minimized. In addition, this rotational moment can be received in a dispersed manner over the entire extension direction of the three longitudinal grooves 115, 125, and 135 formed in each of the tooth root-corresponding portions 110, 120, and 130 of the implant 100, thereby preventing the loosening of the implant 100 that occurred in the prior art.

[0087] Next, a second embodiment of the present invention will be described with reference to the drawings. Fig. 4(a-1) is a schematic perspective view showing an implant 200 according to the second embodiment of the present invention, as viewed from the labial side, with a crown 20 placed on its abutment (not shown in the drawing), and Fig. 4(a-2) is a cross-sectional view of Fig. 4(a-1) cut in a direction perpendicular to the extension direction of the tooth root equivalents 210, 220. Fig. 4(b-1) is a schematic perspective view of an implant 200 according to the second embodiment of the present invention, as viewed from the lingual side, with a crown 20 placed on its abutment (not shown in the drawing), and Fig. 4(b-2) is a cross-sectional view of the implant 200 cut in a direction perpendicular to the extension direction of the tooth root equivalents 210, 220.

[0088] An implant 200 according to a second embodiment of the present invention (hereinafter referred to as "the implant 200" or simply "implant 200") is an implant used in place of a premolar in the upper jaw or a molar in the lower jaw.

[0089] This implant 200 is composed of two separate tooth root equivalent portions 210, 220 and a single crown prosthesis portion 250 formed by joining and connecting the two tooth root equivalent portions 210, 220 at the base ends of the two tooth root equivalent portions 210, 220. An abutment (not shown in the drawings) is detachably attached to the portion of the crown prosthesis portion 250 opposite to the portion where the tooth root equivalent portions 210, 220 are connected.

[0090] In addition, on the opposing inner surfaces of the two tooth root equivalents 210, 220 extending side by side, one or two (shown as two in this embodiment) vertical grooves 215, 225 having a predetermined depth are formed in the surface area extending from the tip side of each tooth root to the base side of the tooth root, starting from the tip side or its vicinity toward the base side of the tooth root, over a length that is approximately one-third of the length of each tooth root equivalent 210, 220.

[0091] Furthermore, in the surface region excluding the surface region below the cervical equivalent region 255 of the crown prosthesis 250 and the predetermined regions where the longitudinal grooves 215, 225 of each root equivalent portion 210, 220 are formed, lateral grooves 211, 221 of a predetermined depth are formed side by side at predetermined intervals from the lower side of the cervical equivalent region 255 to the root tips of each root equivalent portion 210, 220. In this embodiment, four lateral grooves 211, 221 are formed side by side at predetermined intervals and depths, but the number of lateral grooves is not necessarily limited to this number.

[0092] Furthermore, in the implant 200 according to this embodiment, of the surface region R-2 extending from the lower end of the root equivalent portions 210, 220 to the underside of the cervical equivalent region 255 of the crown prosthesis portion 250, the surface region Ra-2 (see region Ra-2 in Figure 4), which is approximately two-thirds of the surface from the lower end of the root equivalent portions 210, 220 toward the cervical equivalent region 255 of the crown prosthesis portion 250, is formed with a large surface roughness, while the surface region Rb-2 (see region Rb-2 in Figure 4), which is approximately one-third of the surface extending to the underside of the cervical equivalent region 255, is formed with a small surface roughness.

[0093] In the second embodiment shown in FIG. 4, if the major axis (the horizontal length of the crown prosthesis 250 in these drawings) of the crown prosthesis 250 shown in FIGS. 4(a-2) and 4(b-2) is approximately 8 mm (mm) and the minor axis (the vertical length of the crown prosthesis 250 in these drawings) is approximately 6 mm (mm), then the surface roughness of the surface treatment is equivalent to that of the first embodiment as described above, and the dimensions of the width and depth of the horizontal grooves 211, 221 and the length, width and depth of the vertical grooves 215, 225, which are characteristic parts of this second embodiment, are also equivalent to those of the first embodiment.

[0094] The implant 200 according to the second embodiment is made of titanium or a titanium alloy, which has excellent biocompatibility, as in the second embodiment, but may also be made of other materials such as zirconium or zirconia (zirconium oxide). Alternatively, the implant may be made of a resin material such as PEEK (polyether ether ketone) or carbon-reinforced polymer, which has excellent biocompatibility, strength, and ease of fabrication using a 3D printer.

[0095] Furthermore, the implant 200 according to this embodiment is manufactured through the same manufacturing process as that of the first embodiment. That is, it is completely different from the conventional manufacturing process of cutting a single rod-shaped body. Specifically, implant-compatible three-dimensional information representing the size and shape of the integrated root portion, crown prosthesis portion, and abutment of the original natural tooth corresponding to the site where the implant 200 is to be embedded in the jawbone is obtained as 3D data by CT scanning, and the desired implant 200 is formed using a 3D printer based on this implant-compatible three-dimensional information obtained as 3D data.

[0096] Below is a description of an example of how to use a 3D printer to manufacture an implant 200 made from a titanium alloy. This manufacturing process is carried out based on information from a CT scan that captures a three-dimensional image of the natural tooth before it is replaced with the implant 200. In this process, first, titanium powder that meets medical biocompatibility is prepared, and the desired implant 200 is created using selective laser sintering (SLS) or electron beam melting (EBM).

[0097] This results in the formation of longitudinal grooves 215, 225 of a predetermined depth extending a certain length from the tip of the tooth root-corresponding portions 210, 220, which are unique to the present invention, and lateral grooves 211, 221 of a predetermined depth at predetermined intervals from the lower side of the tooth neck-corresponding region 255 (see dotted line 255a in the figure) to the tip of the tooth root-corresponding portions 210, 220, and a desired surface roughness in the predetermined surface region R-2. After performing a heat treatment such as HIP treatment to improve mechanical strength, the surface of the implant 200 is subjected to a surface treatment such as sandblasting so that the surface has the unique surface roughness of the present invention. In this way, the implant 200 is individually manufactured, having the same shape as the natural tooth before it is replaced with the implant 200 and the unique longitudinal grooves 215, 225, lateral grooves 211, 221, and surface roughness of the present invention.

[0098] Furthermore, when manufacturing implants using a 3D printer with highly biocompatible metals such as titanium, titanium alloys, zirconium, and zirconia, it is preferable to selectively consider and implement the option of individually manufacturing higher quality implants by further heat treating or densifying the entire implant after creating the implant through the process described above, taking into consideration the site where the implant will be placed and the large occlusal forces that will act on the implant over the long term.

[0099] Specifically, the details are as follows: Improvements in mechanical strength are as follows: After titanium or titanium alloys are created using a 3D printer, they are subjected to heat treatment (solution treatment, aging treatment, etc.) to remove any microscopic defects or stress remaining inside. This improves the strength and durability of the implant.

[0100] Densification processes include sintering and diffusion bonding, especially when using electron beam deposition or selective laser manufacturing (SLM), to ensure the proper density of the metallurgical structure after implant formation.

[0101] In this way, it may be desirable to consider selectively performing sintering, other heat treatment processes, and densification processes as appropriate to improve the final product quality after the implant has been formed using a 3D printer.

[0102] Next, the effects of the second embodiment will be described. Note that the first embodiment has three separate tooth root-equivalent portions 110, 120, and 130, while the second embodiment has two separate tooth root-equivalent portions 210 and 220 of the implant 200, which is a structural difference between the two.

[0103] On the other hand, the second embodiment is an implant used in place of maxillary premolars or mandibular molars. The implant 200 used in place of maxillary premolars is embedded in the maxilla, which has a high bone density, and the complex way in which the occlusal force accompanying the molar grinding movement acts is similar to that of the maxillary molars described in the first embodiment, although there are differences in the magnitude of the force.

[0104] Similarly, with regard to the implants 200 used in place of mandibular molars, once implanted as implants 200, the bone bonding strength is stronger than in the case of the maxilla, because the bone density of the mandible is dense. However, apart from this, the degree of application of complex forces and moments based on the molar grinding movement acting on these implants 200 implanted in place of mandibular molars is basically the same as in the first embodiment.

[0105] In other words, when considering the respective effects, the second embodiment also exhibits the same first and second effects as the first embodiment, so the second embodiment will not be described in detail here, as these effects are the same as those of the first embodiment.

[0106] A number of unique functions and effects of the implant 100 according to the second embodiment of the present invention (hereinafter referred to as "this embodiment") will be described. Note that some of the drawings will be described only in text, with reference to the drawings used in the first embodiment. Therefore, the reference numerals in the following text will be described only in text, without showing the reference numerals themselves in drawings such as Figures 2 and 3. That is, although Figures 2 and 3 are drawn assuming that there are three tooth root equivalents, the description of the functions and effects of this second embodiment will be made assuming that there are two tooth root equivalents.

[0107] First, a first unique effect of the second embodiment will be described. This second embodiment achieves the same effect as the process from FIG. 2 to FIG. 3 used in the description of the effect of the first embodiment. Specifically, FIG. 2 shows the gap between the jawbone 80 and the implant 200 immediately after the extraction of the original natural tooth that has become loose and is no longer performing its original function and the necessary treatment has been performed, i.e., the gap slightly thicker than the periodontal ligament surrounding the tooth root equivalent portions 210 and 220, as well as the narrow space formed by the lateral grooves 211 and 221 and the longitudinal grooves 215 and 225 of the implant 200, as shown in the figure. On the other hand, in FIG. 3, the absence of the margins in the figure makes it visually clear that the gap and space shown in FIG. 2 are quickly filled by bone growth, resulting in complete bonding between the jawbone and the implant 200.

[0108] Let's compare this to the process of placing a conventional implant. With conventional implants, after the original natural tooth that no longer functions properly is extracted, the gum area is sutured and the entire natural tooth is left missing for about six months. During this process, the natural tooth that formed in the jawbone after the extraction and the surrounding periodontal ligament are removed, and the large space created in its place is filled with a jawbone growth promoter or similar.

[0109] This requires a complex procedure in which the surrounding bone grows and fills the space, then the sutured area is re-incised, a hole is drilled into the jawbone with an implant drill, and the implant is then screwed in.

[0110] However, as is clear from the above description of the structure of the implant 200 according to this embodiment, the present invention does not require a series of complicated operations or procedures as in the case of conventional implant embedding.

[0111] In other words, as is clear when compared with this conventional method, by using the implant 200 according to the present invention, it is possible to quickly and securely embed the implant 200 without the inconvenience of food particles getting caught or stuck during meals due to the tooth being left missing for a long period of time after extraction, and without the need to perform work or procedures that place a considerable physical burden on the implant recipient, such as drilling a hole in the jawbone after the jawbone has fully grown to close the space left after the tooth has been extracted.

[0112] In addition, according to the present invention, as explained at the beginning of this second embodiment, large spaces remain after tooth extraction (the entire virtual space area inside the dotted circle in FIG. 2(a) and the entire virtual space area to the right of the dotted vertical line in FIG. 2(b)), and it is necessary to wait until the bone shown by the small dots around this area grows and fills these spaces. Even if a bone growth material or the like is inserted, it is clear that a certain amount of time is required for the bone to grow to the point where a hole that serves as the base for implant placement can be drilled using a conventional implant placement drill used in dentistry.

[0113] However, as is clear from the figures showing the effect of this second embodiment, the present invention has the special advantage that the gap between the root-equivalent portions 210, 220 of the implant and the jawbone 80 is limited to a fairly narrow spatial area, making it possible to fill this narrow spatial area in a short period of time through bone growth.

[0114] This can be visually understood from the narrow margin between the dotted circle and the solid line portion in the vicinity of the dotted circle in Fig. 2(a) and the narrow margin between the dotted vertical line and the solid line portion in the vicinity of the right side in Fig. 2(b), which are spatial regions depicted as cases that actually occur in the first embodiment of the present invention. Note that the special advantages of the second embodiment described here can be said to be unique special advantages possessed by all of the first and third embodiments and their modifications, i.e., only by the present invention.

[0115] Next, a second unique effect of the implant 200 according to the second embodiment will be described. Of the surface region R-2 extending from the root-equivalent ends of the two root-equivalent portions 210, 220 of the implant 200 according to the second embodiment to the lower side of the neck-equivalent region 255 occupying the upper side of the crown prosthesis 250, the surface roughness is formed roughly in the lower approximately two-thirds of the surface region (see region Ra-2 in FIG. 1(a)) extending from the lower ends of the root-equivalent portions 210, 220 toward the neck-equivalent region 255 of the crown prosthesis 250, and the surface roughness is formed finely in the upper approximately one-third of the surface region (see region Rb-2 in FIG. 4(a)) extending to the lower side of the neck-equivalent region 255.

[0116] First, the effect of the surface region Rb-2, which has a fine surface roughness, will be described. After the implant 200 is placed, the portion with the fine surface roughness is located closer to the gums. This leaves almost no gap between the portion with the fine surface roughness of the implant 200 and the surrounding jawbone 80 that is in close contact with it, greatly increasing the degree of adhesion.

[0117] As a result, it becomes difficult for microorganisms such as fungi and bacteria to invade between the gums and the implant 200. Furthermore, since the degree of adhesion is extremely high between the surface region Rb-2 with the fine surface roughness and the jawbone 80 as described above, even if microorganisms invade the gums and the region corresponding to the tooth neck 155, the microorganisms such as fungi and bacteria are reliably prevented from invading deeper in the implant 200, that is, between the jawbone 80 and the surface region Ra-2 with the rougher surface roughness of the surface region R-2 of the implant 200.

[0118] In this way, microorganisms such as fungi and bacteria can penetrate deep into the tooth root equivalent parts 210, 220 of the implant 200, causing inflammation in these parts, thereby preventing the occurrence of implant peridontitis and reliably avoiding destruction of the interface between the implant 200 and the jawbone 80.

[0119] Structural destruction between the deep part of the implant and the jawbone caused by peri-implantitis induces implant mobility, which progresses irreversibly when occlusal forces are applied, eventually impairing the function of the implant itself, necessitating its removal again and replacement with a newer implant.

[0120] Therefore, if this happens, it will impose a physical and financial burden on the implant recipient. Also, implanting a second implant will be a larger-scale procedure, and depending on the original thickness and shape of the jawbone 80 and the nerve routing of the jawbone 80, it may not be possible to implant a second implant, and the first implant may end up being wasted.

[0121] However, according to the present invention, for the reasons mentioned above, such extremely troublesome peri-implantitis can be prevented in advance, and it can be easily understood that the present invention has the unique effect of allowing the implant 200 to be used for a long period of time once it is embedded.

[0122] Furthermore, after implant 200 is embedded, region Ra-2 with a rough surface roughness penetrates further into jawbone 80, which is further away from the gums than region Rb-2 with a fine surface roughness, and becomes integrated with jawbone 80. Since the surface roughness of implant 100 is rough, the surface area of ​​implant 200 in this region naturally increases, and as a result, the area of ​​contact with jawbone 80 also increases. In this case, this portion becomes the base of implant 100, and this increased area of ​​contact allows the base portion of implant 200 to firmly contact jawbone 80, making it possible to maintain a good embedded state of implant 200 for a longer period of time.

[0123] Next, a third unique effect of the implant 200 according to the second embodiment will be described. As will be explained at the end of this specification, the bone density of the maxilla is denser than that of the mandible. This is due to structural and physiological reasons of the jawbone 80, and the difference in bone density between the two is inevitable. Therefore, if the implant 200 is placed in place of a maxillary premolar as in the past, various problems will arise.

[0124] Specifically, as explained in the section on problems to be solved by the invention, molars play an important role as the primary digestive organs, tightly gripping and shearing hard foods such as meat, firm vegetables, and nuts not only through the vertical bite of the upper and lower molars but also through a grinding motion known as a pestle action, before swallowing them.

[0125] Therefore, when conventional implants, which are basically rod-shaped components with a circular cross section, are implanted in the upper jaw, where bone density is low, it is like driving a stake into soil with poor foundations.Thus, although it is possible to implant a thicker implant in the area of ​​the upper premolars, which is deep in the jawbone, it is ultimately just a single rod-shaped implant driven in like a stake.

[0126] In this embodiment, under such circumstances where complex occlusal movements, including not only the above-mentioned up-and-down occlusal movements but also front-to-back and left-to-right grinding movements, are necessarily constantly occurring, occlusal forces act in three dimensions on the upper portion of the implant 200 embedded in the maxilla (the portion that is covered and fixed with the dental crown 20). As a result, moments in complex directions constantly act on the tip of the implant relative to the side of the implant embedded in the jawbone 80.

[0127] The problem here is that conventional implants placed in place of premolars in the maxilla are basically rod-shaped members with circular cross sections, as mentioned above. Therefore, when occlusal force acts on the implant abutment in a direction that forms a certain angle with the direction in which the implant extends, the moment acting on the conventional implant at this time results in an excessive pressing force acting between a small portion of the implant's circumferential surface and a small portion of the inner circumferential surface of the jawbone that is in close contact with it.

[0128] Due to the action of localized and concentrated components of excessive bite force on the maxilla, which has a high bone density, excessive pressing force from the conventional implant acts on localized parts of the jawbone 80 with point contact rather than so-called surface contact. As a result, fine cracks occur in localized parts of the jawbone 80. Once a crack occurs, the application of similar force will cause the crack to grow and lead to destruction of the jawbone in that area.

[0129] As mentioned above, bite forces act in various directions on the maxillary premolars during molar grinding, which can cause damage to various parts of the maxilla that come into contact with the peri-implant surface, eventually causing the implant to become loose and making it impossible to continue using, which can lead to situations where the implant needs to be re-implanted.

[0130] However, the implant 200 used in place of a maxillary premolar according to the present invention has root-equivalent portions 210, 220 that are bifurcated like natural teeth, so unlike the conventional example of driving a single stake into soil that is not completely solid, it is like having two solid legs that are completely buried in the soil.

[0131] As a result, even if a force in a particular direction associated with molar grinding acts on the crown prosthesis portion 250 of the implant 200, the other of the remaining tooth root equivalents 210, 220, which is different from the one of the tooth root equivalents 210, 220 to which the occlusal force is applied, exerts a repulsive force that braces itself to prevent the implant 200 from falling over. This prevents a large force due to the occlusal force or the moment resulting therefrom from being applied to a localized area of ​​the implant 200's connection with the bone. As a result, it is possible to prevent localized destruction of the jawbone 80 around the implant due to the localized concentration of load caused by the moment generated by molar grinding, as in the conventional case.

[0132] Next, a fourth unique effect of the implant 200 according to the second embodiment will be described. For example, when trying to grind hard meat or sticky gummy candy by repeatedly shifting the upper and lower premolars clockwise and counterclockwise around the axis of the upper premolar while the upper and lower premolars are in occlusion, a force is exerted that rotates the crown of the upper premolar together with the abutment in a clockwise or counterclockwise direction. Therefore, with a conventional implant that has a male thread formed around a rod-shaped body with a deformed cross section, the operation is like repeatedly tightening and loosening a screw, which is like tightening and loosening a bolt.

[0133] As a result, when conventional implants are placed, loosening occurs between the implant and the upper jaw, which has a low bone density, particularly in the case of upper premolars that are completely screwed into the upper jaw and integrated into it.Eventually, this loosening increases, and there is a risk that the part of the upper jaw that is connected to the implant will break down, as described above, causing the implant to become loose.

[0134] On the other hand, in this embodiment, the opposing inner surfaces of each root equivalent portion 210, 220 of the implant 200 are configured to have one or two (one in the drawings) vertical grooves 215, 225 having a predetermined depth extending from the root tip side (lower end side in Figures 4(a-1) and (b-1)) to the root base side (upper end side in Figures 4(a-1) and (b-2)) starting from the root tip side toward the root base side, over a length of approximately one-third of the length of each root equivalent portion 210, 220.

[0135] In this embodiment, the longitudinal grooves 215, 225 are formed at a distance quite close to the central axis of the implant 200, and the jawbone 80 penetrates and couples to the aforementioned locations of each tooth root-corresponding portion 210, 220 over the entire extension direction of the longitudinal grooves 215, 225, thereby achieving the following unique effects. Specifically, even if a force that repeatedly rotates the implant 200 around its axis in clockwise and counterclockwise directions due to the special grinding motion described above acts, the rotational moment around the axis of the implant 200 caused by this force can be minimized. In addition, this rotational moment can be received in a dispersed state over the entire extension direction of the two longitudinal grooves 215, 225 formed in each tooth root-corresponding portion 210, 220 of the implant 200, thereby preventing the loosening of the implant 200 that occurred in the prior art.

[0136] Next, a third embodiment of the present invention will be described with reference to the drawings. Fig. 5(1) is a view of an implant 300 for a maxillary anterior tooth or canine, or a mandibular anterior tooth, canine, or premolar according to the third embodiment of the present invention, viewed from the lingual side, with a crown 30 placed on its abutment (not shown in the drawing because it has a configuration equivalent to the abutment shown in Fig. 1). Fig. 5(1-a) is a cross-sectional view of Fig. 5(1) taken in a direction perpendicular to the extension direction of the tooth root equivalent portion 310, of a portion not including the longitudinal groove 315 formed along the extension direction of the tooth root equivalent portion 310, and Fig. 5(1-b) is a cross-sectional view of Fig. 5(1) taken in a direction perpendicular to the extension direction of the tooth root equivalent portion 310, of a portion including the longitudinal groove 315 formed along the extension direction of the tooth root equivalent portion 310. 5(2) is a perspective view of an implant 300 for an upper front tooth or canine, or a lower front tooth, canine, or premolar according to a third embodiment of the present invention, with a crown 30 placed on its abutment (illustration and reference numerals are omitted in FIG. 5 for the same reasons as in the second embodiment). FIG. 5(2-c) is a cross-sectional view of a portion of FIG. 5(2) and FIG. 5(3) that does not include the longitudinal groove 315 formed along the extension direction of the tooth root equivalent portion 310, cut in a direction perpendicular to the extension direction of the tooth root equivalent portion 310. FIG. 5(2-d) is a cross-sectional view of a portion of FIG. 5(2) and FIG. 5(3) that includes the longitudinal groove 315 formed along the extension direction of the tooth root equivalent portion 310, cut in a direction perpendicular to the extension direction of the tooth root equivalent portion 310. FIG. 5(3) is a perspective view showing, in partial cross section, a portion along a longitudinal groove 315 formed in a root-equivalent portion 310 of an implant 300 for an upper front tooth or canine, or a lower front tooth, canine, or premolar according to a third embodiment of the present invention, with a crown 30 placed on its abutment (not shown in the figure because it has an equivalent configuration to the abutment shown in FIG. 1).

[0137] An implant 300 according to a third embodiment of the present invention (hereinafter referred to as "this implant 300" or simply "implant 300") is an implant 300 used in place of an upper front tooth or canine, or a lower front tooth, canine, or premolar. This implant 300 comprises one tooth root equivalent portion 310 and a crown prosthesis portion 350 formed continuous with the base end of this single tooth root equivalent portion 310. An abutment, not shown in the drawings for the same reason as in the second embodiment, is detachably attached to the end of the crown prosthesis portion 350 opposite the tooth root equivalent portion 310.

[0138] On the lingual side of the posterior surface of the root equivalent portion 310, one or two (one in this embodiment) longitudinal grooves 315 having a predetermined depth are formed, which extend from the root tip or its vicinity in the surface region from the root tip to the root base end side over a length of approximately one-third of the length of the root equivalent portion 310 toward the root base end side.

[0139] Furthermore, in the surface region excluding the region below the cervical equivalent region 355 of the crown prosthesis 350 and the region where the longitudinal grooves are formed in the root equivalent portions 310, five lateral grooves 311 of a predetermined depth are formed at predetermined intervals in this embodiment from the lower side of the cervical equivalent region 355 of the crown prosthesis 350 to the root tip of each root equivalent portion 310. Note that, in this embodiment, five lateral grooves 311 of a predetermined depth are formed side by side at predetermined intervals and depths, but the number of lateral grooves is not necessarily limited to this number.

[0140] Furthermore, in the implant 300 according to this embodiment, of the surface region R-3 extending from the lower end of the root equivalent portion 310 to the underside of the cervical equivalent region 355 of the crown prosthesis portion 350, the surface region Ra-3 (see region Ra-3 in Figure 5), which is approximately two-thirds of the surface region from the lower end of the root equivalent portion 310 toward the cervical equivalent region 355 of the crown prosthesis portion 350, is formed with a coarse surface roughness, while the surface region Rb-3 (see region Rb-3 in Figure 5), which is approximately one-third of the surface region extending to the underside of the cervical equivalent region 355, is formed with a fine surface roughness.

[0141] 5 is the same as that of the first and second embodiments, and the width and depth of the lateral groove 311 are also the same as those of the first and second embodiments. On the other hand, in the third embodiment, since the tooth root equivalent portion 310 is made up of a single piece, the length of the longitudinal groove 315 is slightly longer than that of the longitudinal groove 315 of the first and second embodiments, and the width and depth are also slightly larger than those of the first and second embodiments.

[0142] As described above, the implants according to the third embodiment are used in place of the front teeth and canines of the upper jaw and the front teeth, canines, and premolars of the lower jaw, and are therefore depicted in the drawings with a common shape. However, the shape of each implant is unique depending on the type of natural tooth, which will be explained below.

[0143] The difference in the third embodiment is the specific shapes of the implants used in place of the canines and front teeth of the upper and lower jaws, and the premolars of the lower jaw. The root-equivalent portions of the implants corresponding to the front teeth and canines of the upper and lower jaws actually have a rounded triangular shape when cut perpendicular to the axial direction, and the lip side in particular is a flat surface with a large curvature, which is shaped to resist the axial rotation moment that occurs during occlusion.

[0144] In addition, the root-equivalent portion of the implant corresponding to the premolar in the mandible has a cross-section that is triangular with rounded edges when cut perpendicular to the axial direction, with the lip side in particular being a flat surface with a large curvature, and the tongue side having the short side of a trapezoid, making it shaped to resist the bite forces in various directions associated with the molar grinding movement that occurs during biting and the accompanying moments.

[0145] In other words, even in the implant of the third embodiment, which has a single root-equivalent portion, although it is not shown in detail in the drawings for convenience of explanation, it has basically the same shape as the incisors, canines, and premolars of the upper and lower jaws, which are natural teeth of the lower jaw.

[0146] The implant 300 according to the third embodiment is made of titanium or a titanium alloy, which has excellent biocompatibility, as in the first and second embodiments, but may also be made of other materials such as zirconium or zirconia (zirconium oxide). Alternatively, the implant may be made of a resin material such as PEEK (polyether ether ketone) or a carbon-reinforced polymer, which has excellent biocompatibility, strength, and ease of fabrication using a 3D printer.

[0147] Furthermore, the implant 300 according to this embodiment is manufactured through the same manufacturing process as that of the first embodiment. That is, it is completely different from the conventional manufacturing process of cutting a single rod-shaped body. Specifically, implant-compatible three-dimensional information representing the size and shape of the integrated root portion, crown prosthesis portion, and abutment of the original natural tooth corresponding to the site where the implant 300 will be embedded in the jawbone is obtained as 3D data by CT scanning, and the desired implant 300 is formed using a 3D printer based on this implant-compatible three-dimensional information obtained as 3D data.

[0148] The method for manufacturing the implant according to the third embodiment is basically the same as the method for manufacturing the implant according to the modified example of the third embodiment, which will be described later. Therefore, when manufacturing the implant according to the modified example of the third embodiment, which will be described later, this method for manufacturing the implant is applied. Therefore, when describing the method for manufacturing the modified example of the third embodiment, the description of the method for manufacturing the modified example of the third embodiment will be used and will be omitted.

[0149] Below is an explanation of an example of how to use a 3D printer to manufacture an implant 300 made from a titanium alloy. This manufacturing process is based on information from a CT scan that captures a three-dimensional image of the natural tooth before it is replaced with the implant 300. In this process, first, titanium powder that meets medical biocompatibility is prepared, and the desired implant 300 is created using selective laser sintering (SLS) or electron beam melting (EBM).

[0150] This results in a configuration in which longitudinal grooves 315 of a predetermined depth extending a certain length from the tip of root-equivalent portion 310, which are unique to the present invention, are provided, and lateral grooves 311 of a predetermined depth are provided at predetermined intervals from the lower side of neck-equivalent region 355 (see dotted line 355a in the figure) to the tip of root-equivalent portion 310, and a predetermined surface region R-3 is provided with a desired surface roughness. After a heat treatment such as HIP treatment is performed to improve the mechanical strength, a surface treatment such as sandblasting is performed so that the surface of implant 300 has the unique surface roughness of the present invention. In this way, implants 300 are individually manufactured that have the same shape as the natural tooth before being replaced with implant 300 and have the unique longitudinal grooves 315, lateral grooves 311, and surface roughness of the present invention.

[0151] Furthermore, when manufacturing implants using a 3D printer with highly biocompatible metals such as titanium, titanium alloys, zirconium, and zirconia, it is preferable to selectively consider and implement the option of individually manufacturing higher quality implants by further heat treating or densifying the entire implant after creating the implant through the process described above, taking into consideration the site where the implant will be placed and the large occlusal forces that will act on the implant over the long term.

[0152] Specifically, the details are as follows: Improvements in mechanical strength are as follows: After titanium or titanium alloys are created using a 3D printer, they are subjected to heat treatment (solution treatment, aging treatment, etc.) to remove any microscopic defects or stress remaining inside. This improves the strength and durability of the implant.

[0153] Densification processes, particularly when using electron beam deposition or selective laser manufacturing (SLM), can involve sintering or diffusion bonding to ensure the appropriate density of the metallurgical structure after implant formation.

[0154] In this way, it may be desirable to consider selectively performing sintering, other heat treatment processes, and densification processes as appropriate to improve the final product quality after the implant has been formed using a 3D printer.

[0155] Next, the effects of the third embodiment will be described. In the first embodiment, the tooth root equivalent portions 110, 120, and 130 of the implant are divided into three parts, and in the second embodiment, the tooth root equivalent portions 210 and 220 of the implant are divided into two parts, whereas in the third embodiment, the tooth root equivalent portion 310 of the implant 300 is formed as a single part all the way to the tip, which is a structural difference between the first and second embodiments.

[0156] However, when considering the respective effects, it is clear that the first and second effects of the first embodiment and the first and second effects of the second embodiment also have equivalent effects in the third embodiment, so we will reuse these effects of the first and second embodiments and omit their description here, and only explain the effects unique to the third embodiment below.

[0157] First, the unique effects of the third embodiment will be described, followed by a description of effects equivalent to those of the first and second embodiments for confirmation. The implant 300 according to the third embodiment is used in place of the front teeth and canines of the upper jaw and the front teeth and canines and premolars of the lower jaw, and is different from the first embodiment in that it is not used in place of the upper molars of the upper jaw or the premolars and molars of the lower jaw of the second embodiment. Therefore, the occlusal force acting on the implant 300 according to the third embodiment is applied in a more specific direction than the complex occlusal force associated with the molar grinding movement during occlusion as in the second embodiment.

[0158] Specifically, the front teeth and canines corresponding to the implant 300 of this third embodiment perform the basic function of biting and tearing food by the shearing force generated by the upper and lower jaws biting together.

[0159] Therefore, the occlusal force and moment acting on this portion of the implant 300 act to tilt the implant itself toward the labial side or the lingual side. In some cases, if food to be chewed is caught in a position biased toward either the width direction (left or right direction) of the portion of the crown 30 attached to the implant 300, a torsional moment that twists in a certain direction around the axis of the implant 300 may act in addition to the occlusal force and tilt moment in the tilting direction described above.

[0160] Even in this case, one or two longitudinal grooves 315 (described as one groove in this embodiment and the corresponding drawings) having a predetermined depth are formed on the lingual rear surface of the root-equivalent portion 310, extending over approximately one-third of the length from the lower end of the root-equivalent portion 310 to the cervical region 355 of the crown prosthesis 350, so that the entire surface area of ​​the implant 300, particularly the portions including the horizontal grooves 311 and the longitudinal grooves 315, firmly adheres to the jawbone, thereby preventing the implant 300 from tipping over. In particular, the firmly adhering of the jawbone to the entire longitudinal direction of the longitudinal grooves 315 of the implant 300 also has the effect of preventing twisting of the implant 300, as will be explained below.

[0161] More specifically, even if the torsional force or torsional moment described above is applied, the longitudinal groove 315 formed in a predetermined portion of the tongue side adheres closely to the jawbone 80 (see FIG. 3) along the entire longitudinal direction, dispersing these forces and achieving the effects unique to the present invention. Specifically, this prevents damage to the jawbone at the local site where the implant abuts, which would otherwise occur when forces are applied around the axis, as occurs with conventional implants. This reliably prevents loosening of the conventional implant itself and the resulting movement of the implant.

[0162] Next, we will explain the effects of the third embodiment, which can be achieved in the same way as the first and second embodiments. In the third embodiment, the tooth root equivalent portion 310 of the implant is configured as a single piece extending to the tip.

[0163] On the other hand, there is a structural difference in that the first embodiment is made up of three implant-corresponding portions 110, 120, 130, while the second embodiment is made up of two tooth root-corresponding portions 210, 220.

[0164] The third embodiment is an implant used to replace the front teeth and canines of the upper jaw or the front teeth, canines, and premolars of the lower jaw. This third embodiment provides the same effects as the process from Figure 2 to Figure 3 used in explaining the effects of the first embodiment.

[0165] Specifically, referring to Figure 2, the gap between the jawbone 80 and the implant 300 immediately after the original natural tooth, which has become loose and is no longer performing its original function, has been extracted and the necessary treatment has been performed, that is, the gap which is slightly thicker than the thickness of the periodontal ligament around the root equivalent portion 310, plus the narrow space formed by the horizontal groove 321 and vertical groove 315 of the implant 300, are left as blank spaces in the drawing.

[0166] On the other hand, referring to Figure 3, it can be visually understood that the gaps and spaces shown in Figure 2 are filled in a short time by bone growth, and the jawbone 80 and implant 300 are completely bonded, as there is no blank space in the drawing.

[0167] Let's compare this to the process of placing a conventional implant. With conventional implants, after the original natural tooth that no longer functions properly is extracted, the gum area is sutured, and the entire natural tooth is left in that state for about six months. During this process, the natural tooth that formed in the jawbone after the extraction and the surrounding periodontal ligament are removed, and the large space created in its place is filled with a jawbone growth promoter or similar.

[0168] This requires a complex procedure in which the surrounding bone grows and fills the space, then the sutured area is re-incised, a hole is drilled into the jawbone with an implant drill, and the implant is then screwed in.

[0169] However, as is clear from the above description of the structure of the implant 300 according to this embodiment, the present invention does not require a series of complicated operations and procedures as in the case of conventional implant embedding.

[0170] In other words, as is clear when compared with this conventional method, by using the implant 300 according to the present invention, it is possible to quickly and securely embed the implant 300 without the inconvenience of having the tooth left missing for a long period of time after extraction, which can cause food particles to get caught or stuck during meals, and without the need for work or procedures that place a considerable physical burden on the implant recipient, such as drilling a hole in the jawbone after the jawbone has fully grown and closed the space left after the tooth has been extracted.

[0171] In addition, according to the present invention, as explained at the beginning of this third embodiment, a large space remains after tooth extraction (corresponding to the entire virtual space area inside the dotted circle in FIG. 2(a) and the entire virtual space area to the right of the dotted vertical line in FIG. 2(b)), and it is necessary to wait until the bone shown by the small dots around this area grows and fills this space. Even if a bone growth material or the like is inserted, it is clear that a certain amount of time is required to grow the jawbone to the point where the entire space can be filled with a conventional implant embedding drill used in dentistry to form a base hole for implant embedding.

[0172] However, as is clear from the diagram showing the effect of this third embodiment, the present invention has a special advantage in that it is limited to a fairly narrow space area between the implant and the root of the tooth, and this narrow space area can be filled in a short period of time by bone growth.

[0173] This can be visually understood by referring to the fact that the spatial region depicted as an actual case in the first embodiment of the present invention is, according to the present invention, made up of a narrow margin between the dotted circle in Figure 2(a) and the solid line portion near its inside, and a narrow margin between the dotted vertical line in Figure 2(b) and the solid line portion near its right side.

[0174] Next, a second unique effect of the implant 300 according to the third embodiment will be described. Of the surface region R-3 extending from the root-equivalent end of one root-equivalent portion 310 of the implant 300 according to the third embodiment to the lower side of the neck-equivalent region 355 occupying the upper side of the crown prosthesis 350, the surface roughness is formed to be coarse in the lower two-thirds of the surface region from the lower end of the root-equivalent portion 310 toward the neck-equivalent region 355 of the crown prosthesis 350 (see region Ra-3 in Figures 5(1), (2), and (3)), and the surface roughness is formed to be fine in the upper one-third of the surface region extending to the lower side of the neck-equivalent region 355 (see region Rb-3 in Figures 5(1), (2), and (3)).

[0175] First, the function of the area with a fine surface roughness will be described. After implantation of the implant 300, the area with a fine surface roughness is located close to the gums. This leaves almost no gap between the area with a fine surface roughness of the implant 300 and the surrounding jawbone 80 that is in close contact with it, greatly improving the degree of adhesion.

[0176] As a result, it becomes difficult for microorganisms such as fungi and bacteria to invade between the gums and implant 300. Furthermore, since the degree of adhesion is extremely high between the portion with fine surface roughness and jawbone 80 as described above, even if microorganisms invade the portion between the gums and region corresponding to the tooth neck 355, microorganisms such as fungi and bacteria are reliably prevented from invading deeper portions of implant 300, that is, between the portion of surface region R-3 of implant 300 with rougher surface roughness and the jawbone.

[0177] In this way, the occurrence of implant peridontitis caused by microorganisms such as fungi and bacteria penetrating deep into the tooth root equivalent portion 310 of the implant 300 and causing inflammation in this portion is prevented, and destruction of the interface between the implant 300 and the jawbone 80 is reliably avoided.

[0178] Structural destruction between the deep part of the implant and the jawbone 80 due to peri-implantitis induces implant mobility, which progresses irreversibly when occlusal forces are applied, eventually impairing the function of the implant itself, making it necessary to remove the implant again and replace it with a newer implant.

[0179] Therefore, if this happens, it will impose a physical and economic burden on the implant recipient. Furthermore, implanting a second implant will be a larger-scale procedure, and depending on the original thickness and shape of the jawbone 80 and the nerve routing of the jawbone 80, it may become impossible to implant a second implant, and the first implant placement may end up being a waste.

[0180] However, according to the present invention, for the reasons mentioned above, such extremely troublesome peri-implantitis can be prevented in advance, and it can be easily understood that the present invention has the unique effect of allowing the implant 300 to be used for a long period of time once it has been placed.

[0181] Furthermore, after implant 300 is embedded, region R-3a with a rough surface roughness penetrates further into jawbone 80, which is further away from the gums than region R-3b with a fine surface roughness, and becomes integrated with jawbone 80. Since the surface roughness of implant 300 is rough, the surface area of ​​implant 300 in this region naturally becomes larger, and as a result, the area of ​​contact with jawbone 80 also increases.

[0182] In this case, this part becomes the root part of the implant 100, and the increased contact area allows the root part of the implant 300 to adhere firmly to the jawbone 80, making it possible to maintain a good embedded state of the implant 300 for a longer period of time.

[0183] As mentioned above, the difference in the third embodiment is the specific shapes of the implants used in place of the canines and front teeth of the upper and lower jaws, and the premolars of the lower jaw. The root-equivalent portions of the implants corresponding to the front teeth and canines of the upper and lower jaws have a rounded triangular periphery on the cross section when cut perpendicular to the axial direction, and the lip side in particular has a flat surface with a large curvature, so that it has a shape that can resist the torsional moment around the axis that occurs during occlusion.

[0184] In addition, the root-equivalent portion of the implant corresponding to the premolar in the mandible has a cross-section that is triangular with rounded edges when cut perpendicular to the axial direction, with the lip side in particular being a flat surface with a large curvature, and the tongue side having the short side of a trapezoid, making it shaped to resist the various directional biting forces and accompanying moments that accompany the molar grinding movements that occur during biting.

[0185] In other words, even in the implant of the third embodiment, which has a single root equivalent portion, although it is not shown in detail in the drawings for the sake of convenience, it has basically the same shape as the incisors, canines, and premolars of the upper and lower jaws, which are natural teeth of the lower jaw.

[0186] As a result, unlike conventional implants with a substantially circular cross section, the load applied to the jawbone when occlusal force is applied to the implant used in this third embodiment is not concentrated at one local point as with conventional implants, but is distributed over a certain area of ​​the jawbone 80. Similarly, the moment applied to the jawbone due to occlusal force is not concentrated at one local point, but is distributed over a certain area of ​​the jawbone 80.

[0187] In this way, the bite force applied to the jawbone during bite and the resulting moment are not applied in a point contact state to localized parts of the jawbone 80, and the excessive pressing force from the implant 300 acts in a dispersed manner. Therefore, no excessive local stress or localized moment is applied to the jawbone 80, and the occurrence of cracks in the jawbone 80 can be prevented.

[0188] From this point of view, it is possible to prevent the occurrence of local cracks in the jawbone 80 in contact with the surface surrounding the implant, which occurs when a conventional implant corresponding to the third embodiment is used, and to prevent the conventional implant from becoming unstable due to destruction of the jawbone 80 around the crack as the crack grows, thereby preventing further physical, mental, and economic burdens on the implant recipient, such as the need to implant the implant again.

[0189] In addition to the above, particularly when the implant in the third embodiment is used in place of a front tooth, from an aesthetic point of view, it takes a long time for the jawbone to fully grow after the tooth is extracted, so that the missing front tooth is immediately noticeable when engaging in conversation, which causes considerable stress from an aesthetic point of view for conventional implant users; however, this mental stress can also be alleviated by the third embodiment of the present invention.

[0190] Next, a modified example of the third embodiment of the present invention will be described with reference to the drawings. Fig. 6(a-1) is a perspective view of an implant 400 according to a modified example of the third embodiment of the present invention, showing a portion of the longitudinal groove 415 in cross section, with the labial side facing left and the lingual side facing right. Fig. 6(a-2) is a first explanatory view showing the effects of the implant 400 according to the modified example shown in Fig. 6(a-1). Fig. 6(a-3) is a second explanatory view showing the effects of the implant 400 according to the modified example shown in Fig. 6(a-1). Meanwhile, Fig. 6(b-1) is a perspective view of a conventional implant 500. Fig. 6(b-2) is a first explanatory view showing the drawbacks of the conventional implant 500 shown in Fig. 6(b-1). Fig. 6(b-3) is a second explanatory view showing the drawbacks of the conventional implant 500 shown in Fig. 6(b-1).

[0191] An implant 400 according to a modified example of the third embodiment of the present invention (hereinafter referred to as "this implant 400" or simply "implant 400") further has a predetermined inclined region (see the inclined region with a downward slope toward the left side in the figure) formed in the cervical region, which is angled so as to approach the connection side of the abutment 470 with the cervical equivalent region 450 as it moves from the center of the attachment side end face of the abutment 470 to the crown 40 toward the lip side.

[0192] Furthermore, in the implant 400 according to this embodiment, although the drawings do not use dots of varying shades as in the other embodiments, of the surface region from the root end of the root equivalent portion 410 to the lower side of the cervical equivalent region, approximately two-thirds of the surface region from the lower end of the root equivalent portion 410 toward the cervical equivalent region 450 of the crown prosthesis (see region Ra-3 in Figures 5(1), (2), and (3)) has a rough surface roughness, while the remaining approximately one-third of the surface region down to the lower side of the cervical equivalent region (see region Rb-3 in Figures 5(1), (2), and (3)) has a fine surface roughness.

[0193] The surface roughness of the modified example of the third embodiment shown in Figures 6(a-1) and (a-2), the width and depth of the lateral grooves 411, and the length, width and depth of the longitudinal grooves 415 are basically the same as the example of values ​​of the third embodiment shown in Figure 5, so the description of the third embodiment described above will be reused and detailed explanations will be omitted.

[0194] Next, the effects of the modified example of the third embodiment will be described. Note that it is clear that the first and second effects of the first embodiment, the first and second effects of the second embodiment, and the first and second effects of the third embodiment also have equivalent effects in the modified example of the third embodiment, so these effects of the first embodiment will be used and a description thereof will be omitted, and only the effects specific to the modified example of the third embodiment will be described below.

[0195] Immediately after implant 400 is placed in place of a front tooth, whether it is a conventional implant 500 or an implant 400 according to a modified example of the third embodiment, the state of the gums 90 when viewed from the labial side of implant 400 is as shown in Figure 6(a-3), and the metal part of implant 400 is covered by the gums 90, so that from an aesthetic point of view, the metal part of implant 400 is not exposed, for example, during conversation.

[0196] However, there is a problem that biological tissues are prone to shrinkage with age. In particular, in the case of the conventional implant 500 shown in Fig. 6(b-2), the implant 500 for the front teeth is placed in a perfect shape as shown in Fig. 6(a-3) to also adjust the bulge of the gums 90 at the beginning of the implant placement.

[0197] However, as can be seen from Fig. 6(b-2), the upper abutment 550 of the implant 500 protrudes vertically and flatly, including on the lip side, making it very easy for the above-mentioned recession phenomenon to occur over time. As a result, the gums 90 recede from the area shown by the dotted line in Fig. 6(b-2) to the area shown by the fine dots surrounded by the solid line (see the receding gums 91 in Fig. 6(b-2)).

[0198] As a result, as shown in Figure 6(b-3), part of the gum 90 where the implant 500 was placed slips down, and the metal part is exposed to the extent that it can be seen at a glance from the lip side, as in the recessed region 95 below the central crown 40 shown in Figure 6(b-3). In this case, just like when dentures are fastened with metal clasps, the metal part is immediately visible from the lip side when you open your mouth while talking with a friend, and from an aesthetic point of view, the purpose of placing the costly implant 500 is completely lost.

[0199] On the other hand, in the case of the modified example of the third embodiment of the present invention, a predetermined inclined region 451 (see the inclined region 451 with a downward slope toward the left side in the figure) is formed so that the cervical region 450 of the implant 400 approaches the jawbone (approaching the tooth root equivalent side) as it moves from the center toward the labial peripheral region. As a result, shortening of the gums 90 does not occur after a certain period of time, as occurs when the above-mentioned conventional implant 500 is implanted, and excellent aesthetics can be maintained for a long period of time after implantation, as shown in Figures 6(a-2) and 6(a-3).

[0200] Finally, regarding one of the issues described in the section on problems to be solved by the invention, (c) the physiological tissue structure reason why the bone density of the upper jaw is sparse and dense compared to that of the lower jaw, the inventor, who has actually been involved in dental care for many years, provides an explanation.

[0201] The reason for the high bone density of the maxilla is mainly due to its anatomical structure and function. Specifically, it is closely related to the structure and composition of the bone, and the maxilla is made up of a large proportion of spongy bone (spongy bone) and a small proportion of compact bone (compact bone). Trabecular bone has many voids and bone marrow inside, making it less dense.

[0202] More specifically, the formation of a large cavity called the maxillary sinus further reduces bone density. The maxillary sinus contributes to the resonance of breathing and speech, but it also reduces bone mass and causes bone density to decrease.

[0203] This means that the maxilla requires sufficient blood flow and metabolism. In other words, the maxilla has an abundant blood flow and is a site where bone remodeling (reconstruction) is actively carried out. This high metabolic activity is thought to be one of the reasons that bone density remains relatively dense. This is even more pronounced compared to the mandible. Therefore, the mandible tends to contain more compact bone and have sufficient strength.

[0204] The reasons for these differences in bone density are largely related to the fact that they arose as a result of functional differences over the long evolutionary period leading up to modern humans, and that the upper jaw, as part of the skull, supports the facial structure and plays a role in forming cavities such as the nasal cavity, eye sockets, and paranasal sinuses (especially the maxillary sinus).

[0205] On the other hand, the lower jaw is directly responsible for the extremely large force exerted on it during chewing, and so has evolved to increase bone density and the strength of the entire lower jaw.

[0206] In conclusion, the difference in bone density between the upper jaw and the lower jaw is due to structural characteristics (abundance of cancellous bone and presence of maxillary sinus) and evolutionarily required lightweighting and functional differences.

[0207] From the above, it is possible to find the excellent technical significance of the present invention in that the implants to replace the maxillary molars, the maxillary premolars, and the mandibular molars and premolars are each made in individual shapes, and in that special longitudinal grooves are formed in each implant, and in that the surface roughness is changed for each region of the implant. Needless to say, this also applies to the third embodiment and its modifications.

[0208] Finally, a method for manufacturing the implants according to the first to third embodiments and the modified example of the third embodiment, which differs from the method for manufacturing the implants already described, will be described below.

[0209] In carrying out this different manufacturing method, three-dimensional data of the natural tooth to be replaced with the implant of the present invention is obtained by CT scanning in the first step. Then, based on this three-dimensional data, a temporary model of the implant with an individual shape consisting of a wax pattern with the same shape as the natural tooth is transferred to a 3D printer using wax as the material (second step).

[0210] Next, this temporary model of individual shape is used to perform the primary embedding in a coarse-grained embedding agent to form a rough surface roughness over approximately two-thirds of the area from the tip of the root equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis portion (third step).

[0211] Next, the provisional model is secondarily invested with a finer investment material so that the surface of the entire crown prosthesis above the remaining cervical portion is smooth (fourth step).

[0212] Next, after all of these investments have hardened, they are heated together to burn off all of the wax that made up the temporary model (fifth step).

[0213] Then, a metal with excellent biocompatibility as the implant material, such as molten titanium, titanium alloy, or molten zirconium or zirconia, is poured into the implant to cast it with the same shape as the temporary model, with some of the surface unpolished (step 6).

[0214] Finally, with regard to the cervical preparation area, the surface up to the lower side of this area is polished to further smoothen it, thereby producing an implant according to the present invention having different surface roughness in each area of ​​the implant surface (seventh step).

[0215] When attaching an abutment that has been individually prepared in advance to the crown prosthesis of the implant, a female thread for attaching the abutment or an attachment hole for integrating it with cement may be formed in the crown prosthesis of the implant manufactured by the above-mentioned manufacturing method, or a protrusion for attaching to an attachment hole that has been previously formed in the crown prosthesis may be simultaneously formed in the manufacturing process at the stage of forming the implant.

[0216] Furthermore, as a further modification of the above-described manufacturing method, when a temporary model of an implant made of wax is entirely embedded in an investment medium, the temporary model is embedded in the investment medium all at once using an investment medium with very fine particles, and individual implants made of titanium, titanium alloy, zirconium, zirconia, or the like with a smooth surface are first produced by the lost wax method. Then, in order to subsequently form the differences in surface roughness of the surface regions of the implants described in the above-described embodiments and their modifications, a so-called sandblasting method is used to give a rough surface roughness to approximately two-thirds of the region from the root end of the implant's root-equivalent portion to the lower side of the cervical part of the crown prosthesis, and a fine surface roughness to the upper region below the cervical part of the crown prosthesis, and the remaining surface region, i.e., the remaining region other than these surface regions formed with the rough and fine surface roughnesses by the sandblasting method, is polished to be smooth all the way to the lower side of the cervical part, thereby producing an implant according to the present invention.

[0217] This manufacturing method has the advantage that the process using the 3D printer itself is limited to creating a temporary implant model made from wax, and that finished custom-made implants with specific areas of the implant surface roughness can be produced quickly and at low cost using the widely used lost-wax method.

[0218] In addition, when manufacturing implants by sandblasting using metals with excellent biocompatibility such as titanium, titanium alloys, zirconium, and zirconia, it is preferable to selectively consider and implement the individual manufacturing of higher quality implants by further heat treating or densifying the entire implant after creating the implant through the above-mentioned process, taking into consideration the site where the implant will be embedded and the large occlusal forces that will act on the implant over the long term.

[0219] Specifically, the details are as follows: Improvements in mechanical strength are as follows: After titanium or titanium alloys are created using a 3D printer, they are subjected to heat treatment (solution treatment, aging treatment, etc.) to remove any microscopic defects or stress remaining inside. This improves the strength and durability of the implant.

[0220] Densification processes include sintering and diffusion bonding, especially when using electron beam deposition or selective laser manufacturing (SLM), to ensure the proper density of the metallurgical structure after implant formation.

[0221] In this way, it may be desirable to consider selectively performing sintering, other heat treatment processes, and densification processes as appropriate to improve the final product quality after the implant has been formed using a 3D printer.

[0222] It should be emphasized that the first to third embodiments and the modified example of the third embodiment described above are merely illustrative of the present invention, and that the scope of the present invention is not limited to these embodiments.

[0223] Specifically, for example, the material, shape, dimensions, number of horizontal grooves, and number of vertical grooves formed on the implant introduced in the above-mentioned embodiment are not limited to the above-mentioned embodiment and the corresponding drawings, and it should be noted that it is possible to select optimal values, numerical values, and materials for each implant based on the original CT 3D data image as long as they are within a range that achieves the effects of the present invention. [Explanation of symbols]

[0224] 10, 20, 30, 40 tooth crowns 80 Jawbone 90 Gums 91 Receding gingiva 95 Retraction region 100 implants 110, 120, 130 Tooth root equivalent 111,121,131 Yokomizo 115,125,135 Vertical grooves 150 Crown and Prosthetics Department 155 Area equivalent to tooth neck 200 implants 210,220 Tooth root equivalent 211,221 Yokomizo 215,225 Vertical grooves 250 Crown and Prosthetics Department 255 Area equivalent to tooth neck 300 implants 310 Tooth root equivalent 311 Yokomizo 315 Vertical groove 350 Crown and Prosthetics Department 355 Area equivalent to tooth neck 400 implants 410 Tooth root equivalent 411 Yokomizo 415 Vertical groove 450 Area equivalent to tooth neck 451 Slope area 470 Abutment 500 implants 550 Abutment

Claims

1. 1. A method for manufacturing an implant to replace a maxillary molar, comprising: The dental prosthesis is formed by joining three separate root-equivalent portions together at the base end of the three root-equivalent portions, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed, which extend from the tooth root tip or its vicinity in the surface region extending from the tooth root tip side to the tooth root base end side, over a length that is approximately one-third of the length of each tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region excluding a region where the longitudinal grooves are formed in the root equivalent region, in which lateral grooves of a predetermined depth are formed at predetermined intervals from below the cervical equivalent region to a tip of the root of each of the root equivalent regions, The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. The method for manufacturing an implant using a 3D printer based on the implant-corresponding three-dimensional information obtained as the 3D data, so that the implant has different surface roughnesses in different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

2. 1. A method for manufacturing an implant to replace a maxillary molar, comprising: The dental prosthesis is formed by joining three separate root-equivalent portions together at the base end of the three root-equivalent portions, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed, which extend from the tooth root tip or its vicinity in the surface region extending from the tooth root tip side to the tooth root base end side, over a length that is approximately one-third of the length of each tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region excluding a region where the longitudinal grooves are formed in the root equivalent region, in which lateral grooves of a predetermined depth are formed at predetermined intervals from below the cervical equivalent region to a tip of the root of each of the root equivalent regions, The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. Based on the implant-compatible three-dimensional information obtained as 3D data, a temporary model of an individual implant shape is manufactured using a 3D printer using a wax material with a wax pattern that has the same shape as the natural tooth, This temporary model of individual shape is used to primarily embed the tooth in a coarse-grained embedding agent to form a rough surface roughness over approximately two-thirds of the area from the tip of the root equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis portion, Secondary investment is made with finer investment material so that the surface of the entire crown prosthesis above the remaining cervical part of the temporary model becomes smooth. After hardening all of these investments, they are heated together to burn off all of the wax that made up the temporary model. The metal that will become the implant material is poured into the implant, and an implant with the same shape as the temporary model is cast before some of the surface is polished. A method for manufacturing an implant in which the surface of the region where the dental cervical portion is formed is polished to be further smooth down to a lower side of this region, thereby manufacturing an implant having different surface roughnesses for different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

3. 1. A method for manufacturing an implant to replace a maxillary molar, comprising: The dental prosthesis is formed by joining three separate root-equivalent portions together at the base end of the three root-equivalent portions, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed, which extend from the tooth root tip or its vicinity in the surface region extending from the tooth root tip side to the tooth root base end side, over a length that is approximately one-third of the length of each tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region excluding a region where the longitudinal grooves are formed in the root equivalent region, in which lateral grooves of a predetermined depth are formed at predetermined intervals from below the cervical equivalent region to a tip of the root of each of the root equivalent regions, The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. Based on the implant-compatible three-dimensional information obtained as 3D data, a temporary model of an individual implant shape is manufactured using a 3D printer using a wax material with a wax pattern that has the same shape as the natural tooth, The entire temporary model is embedded in an investment material used in the lost wax method, and then the entire investment material is hardened and heated to burn off the wax that constitutes the temporary model. Molten implant material is poured into the implant to create a smooth implant with an entire surface. The entire surface of the implant is smooth, and approximately two-thirds of the area from the tip of the root-equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis is surface-treated by sandblasting to have a rough surface roughness, and the area from the rough surface roughness to the lower side of the cervical portion is surface-treated to have a fine surface roughness, A method for manufacturing an implant in which the surface of the region where the dental cervical portion is formed is polished to be further smooth down to a lower side of this region, thereby manufacturing an implant having different surface roughnesses for different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

4. A method for manufacturing an implant to replace a premolar in the upper jaw or a molar in the lower jaw, comprising: The two separate tooth root equivalents and the prosthetic crown part that is located at the base end of the two tooth root equivalents and joins together are integrally formed, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed, which extend from the tooth root tip or its vicinity in the surface region extending from the tooth root tip side to the tooth root base end side, over a length that is approximately one-third of the length of each tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region excluding a region where the longitudinal grooves are formed in the root equivalent region, in which lateral grooves of a predetermined depth are formed at predetermined intervals from below the cervical equivalent region to a tip of the root of each of the root equivalent regions, The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. The method for manufacturing an implant using a 3D printer based on the implant-corresponding three-dimensional information obtained as the 3D data, so that the implant has different surface roughnesses in different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

5. A method for manufacturing an implant to replace a premolar in the upper jaw or a molar in the lower jaw, comprising: The two separate tooth root equivalents and the prosthetic crown part that is located at the base end of the two tooth root equivalents and joins together are integrally formed, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed, which extend from the tooth root tip or its vicinity in the surface region extending from the tooth root tip side to the tooth root base end side, over a length that is approximately one-third of the length of each tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region excluding a region where the longitudinal grooves are formed in the root equivalent region, in which lateral grooves of a predetermined depth are formed at predetermined intervals from below the cervical equivalent region to a tip of the root of each of the root equivalent regions, The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. Based on the implant-compatible three-dimensional information obtained as 3D data, a temporary model of an individual implant shape is manufactured using a 3D printer using a wax material with a wax pattern that has the same shape as the natural tooth, This temporary model of individual shape is used to primarily embed the tooth in a coarse-grained embedding agent to form a rough surface roughness over approximately two-thirds of the area from the tip of the root equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis portion, Secondary investment is made with finer investment material so that the surface of the entire crown prosthesis above the remaining cervical part of the temporary model becomes smooth. After hardening all of these investments, they are heated together to burn off all of the wax that made up the temporary model. The metal that will become the implant material is poured into the implant, and an implant with the same shape as the temporary model is cast before some of the surface is polished. A method for manufacturing an implant in which the surface of the region where the dental cervical portion is formed is polished to be further smooth down to a lower side of this region, thereby manufacturing an implant having different surface roughnesses for different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

6. A method for manufacturing an implant to replace a premolar in the upper jaw or a molar in the lower jaw, comprising: The two separate tooth root equivalents and the prosthetic crown part that is located at the base end of the two tooth root equivalents and joins together are integrally formed, and An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the mutually opposing inner surfaces of the tooth root equivalent portions, one or two longitudinal grooves having a predetermined depth are formed, which extend from the tooth root tip or its vicinity in the surface region extending from the tooth root tip side to the tooth root base end side, over a length that is approximately one-third of the length of each tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region excluding a region where the longitudinal grooves are formed in the root equivalent region, in which lateral grooves of a predetermined depth are formed at predetermined intervals from below the cervical equivalent region to a tip of the root of each of the root equivalent regions, The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. Based on the implant-compatible three-dimensional information obtained as 3D data, a temporary model of an individual implant shape is manufactured using a 3D printer using a wax material with a wax pattern that has the same shape as the natural tooth, The entire temporary model is embedded in an investment material used in the lost wax method, and then the entire investment material is hardened and heated to burn off the wax that constitutes the temporary model. Molten implant material is poured into the implant to create a smooth implant with an entire surface. The entire surface of the implant is smooth, and approximately two-thirds of the area from the tip of the root-equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis is surface-treated by sandblasting to have a rough surface roughness, and the area from the rough surface roughness to the lower side of the cervical portion is surface-treated to have a fine surface roughness, A method for manufacturing an implant in which the surface of the region where the dental cervical portion is formed is polished to be further smooth down to a lower side of this region, thereby manufacturing an implant having different surface roughnesses for different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

7. A method for manufacturing implants to replace upper front teeth or canines, or lower front teeth, canines, or premolars, A single tooth root equivalent and a crown prosthesis formed in connection with the base end of the single tooth root equivalent are integrally formed, An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the lingual side of the posterior surface of the tooth root equivalent portion, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of the tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region of the root equivalent region excluding a region where the longitudinal grooves are formed, the surface region having a predetermined depth and a predetermined interval between the regions from below the cervical equivalent region to a tip of the root of the root equivalent region; The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. The method for manufacturing an implant using a 3D printer based on the implant-corresponding three-dimensional information obtained as the 3D data, so that the implant has different surface roughnesses in different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

8. A method for manufacturing implants to replace upper front teeth or canines, or lower front teeth, canines, or premolars, A single tooth root equivalent and a crown prosthesis formed in connection with the base end of the single tooth root equivalent are integrally formed, An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the lingual side of the posterior surface of the tooth root equivalent portion, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of the tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region of the root equivalent region excluding a region where the longitudinal grooves are formed, the surface region having a predetermined depth and a predetermined interval between the regions from below the cervical equivalent region to a tip of the root of the root equivalent region; The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. Based on the implant-compatible three-dimensional information obtained as 3D data, a temporary model of an individual implant shape is manufactured using a 3D printer using a wax material with a wax pattern that has the same shape as the natural tooth, This temporary model of individual shape is used to primarily embed the tooth in a coarse-grained embedding agent to form a rough surface roughness over approximately two-thirds of the area from the tip of the root equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis portion, Secondary investment is made with finer investment material so that the surface of the entire crown prosthesis above the remaining cervical part of the temporary model becomes smooth. After hardening all of these investments, they are heated together to burn off all of the wax that made up the temporary model. The metal that will become the implant material is poured into the implant, and an implant with the same shape as the temporary model is cast before some of the surface is polished. A method for manufacturing an implant in which the surface of the region where the dental cervical portion is formed is polished to be further smooth down to a lower side of this region, thereby manufacturing an implant having different surface roughnesses for different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

9. A method for manufacturing implants to replace upper front teeth or canines, or lower front teeth, canines, or premolars, A single tooth root equivalent and a crown prosthesis formed in connection with the base end of the single tooth root equivalent are integrally formed, An abutment is attached to the portion of the crown prosthesis that is connected to the portion corresponding to the tooth root and to the upper portion thereof, On the lingual side of the posterior surface of the tooth root equivalent portion, one or two longitudinal grooves having a predetermined depth are formed extending from the tooth root tip or its vicinity in a surface region extending from the tooth root tip side to the tooth root base end side over a length that is approximately one-third of the length of the tooth root equivalent portion, and a surface region of the crown prosthesis that is a region below the cervical equivalent region and a surface region of the root equivalent region excluding a region where the longitudinal grooves are formed, the surface region having a predetermined depth and a predetermined interval between the regions from below the cervical equivalent region to a tip of the root of the root equivalent region; The implant is placed in the jawbone at a location where it will be placed. 3D information for the implant, which represents the size and shape of the integrated root of the natural tooth, the crown prosthesis, and the abutment, is obtained as 3D data by CT scan. Based on the implant-compatible three-dimensional information obtained as 3D data, a temporary model of an individual implant shape is manufactured using a 3D printer using a wax material with a wax pattern that has the same shape as the natural tooth, The entire temporary model is embedded in an investment material used in the lost wax method, and then the entire investment material is hardened and heated to burn off the wax that constitutes the temporary model. Molten implant material is poured into the implant to create a smooth implant with an entire surface. The entire surface of the implant is smooth, and approximately two-thirds of the area from the tip of the root-equivalent portion toward the lower side of the cervical portion formed in the crown prosthesis is surface-treated by sandblasting to have a rough surface roughness, and the area from the rough surface roughness to the lower side of the cervical portion is surface-treated to have a fine surface roughness, A method for manufacturing an implant in which the surface of the region where the dental cervical portion is formed is polished to be further smooth down to a lower side of this region, thereby manufacturing an implant having different surface roughnesses for different regions of the implant surface, A method for manufacturing an implant, characterized in that, of the entire surface area from the root tip of the root equivalent part to the lower side of the cervical equivalent part of the crown prosthesis, approximately two-thirds of the surface area from the lower end of the root equivalent part of the surface area toward the cervical equivalent part of the crown prosthesis is formed to have a rough surface roughness, and the remaining approximately one-third of the surface area extending to the lower side of the cervical equivalent part is formed to have a fine surface roughness.

10. 10. The method for manufacturing an implant according to any one of claims 7 to 9, characterized in that the implant is manufactured so that a predetermined inclined region is further formed on the peripheral edge of the cervical attachment labial surface of the crown prosthesis, the inclined region being angled so as to approach the root equivalent portion as it moves from the center toward the peripheral edge on the labial side.

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