Dental implant

Abstract

The present invention relates to a dental implant, and more particularly to a dental implant structure capable of preventing fatigue fracture caused by stress concentration in a portion adjacent to an inner polygonal portion of the implant by improving an outer thread structure and the inner polygonal portion structure of the implant. To this end, the present invention is a dental implant for forming an artificial tooth root by being inserted into alveolar bone tissue, characterized in that an outer lower end thread interval in which threads of a high height are formed by machining with a first shaper are formed from a lower end of an outer circumferential surface of the implant to a certain interval upward, and an outer upper end thread interval in which threads of a low height are formed by machining with a second shaper having a different machining surface shape and width from the first shaper are formed upward of the outer lower end thread interval, and the pitches and the thread top widths of the threads of each of the thread intervals machined by the first and second shapers are formed identically.

Description

Technical Field

[0001] This invention relates to a dental implant, and more specifically to a dental implant that can prevent fatigue fracture. Background Technology

[0002] Dental implants, as artificial teeth that can permanently replace missing teeth, are widely used to restore chewing function in partially or completely edentulous jaw areas.

[0003] Dental implants (hereinafter referred to as "implants") should not only function as actual teeth, but should also be made to distribute the load appropriately to the teeth so that they can be used for a long time like actual teeth.

[0004] Alveolar bone implants can be categorized into external and internal connection methods based on the morphology of the abutment and implant integration. External connection methods, characterized by a hexagonal structure protruding upwards from the implant, offer the advantage of relatively robust implants inserted into the bone. However, a disadvantage is that in the initial post-implantation phase, the wider gap between the implant body and the abutment increases the likelihood of bacterial colonization, leading to bone resorption at the boundary.

[0005] The internal connection method involves forming a polygonal groove (hereinafter referred to as the "polygonal part") inside the implant, and the part where the abutment meets the implant is formed into a cone shape, thereby eliminating space for bacterial habitation and minimizing initial bone resorption. The advantage is a high implantation success rate. However, the disadvantage is that due to the structural limitations of the abutment entering the implant body, the possibility of implant breakage within the bone is relatively high.

[0006] Figure 1 and Figure 2 Examples of implant fractures are provided.

[0007] Figure 1 a) Periapical (PA) radiographs of the implant taken 15 years after placement in the patient can confirm the lateral tearing of the implant's upper end. Figure 1 b) As a photograph taken with the implant and abutment removed, it can be confirmed that the implant splits into several parts along the corners of the polygonal portion. Figure 1 c) As shown in the photograph of the abutment and implant to be implanted, it can be seen that the inclined angle of the inclined portion where the abutment and implant meet is large, and it is a structure with an edge surface with a thickness of close to 0 at the upper end of the implant.

[0008] like Figure 1 As the example shows, fractures that occur along the axis of the implant are usually referred to as vertical fractures. Figure 2 a) PA photos and Figure 2 The fractures appearing in the photographs taken after the implants and prostheses are described as transverse fractures occurring in the horizontal direction at the boundary where the abutment body and the polygonal part of the fixation body meet.

[0009] This type of fracture originates from fatigue. Dental implants, which are used to replace lost teeth, are repeatedly subjected to stress from chewing movements, and therefore may experience fatigue fracture.

[0010] In particular, such as Figure 2 As shown in c), during actual chewing movements, not only does the vertical chewing force of the implant in the axial direction act on the abutment, but the horizontal chewing force in the axial direction also acts in combination. Therefore, as shown, the torque is applied, which causes the lower end of the abutment to contact the polygonal portion and apply repeated forces to the polygonal portion.

[0011] pass Figure 3 As can be seen from the previous... Figure 1 As shown, vertical fractures occurring in implants Figure 3 In b), cracks begin to appear and propagate at the crack nucleation site on the bottom surface of the polygonal part indicated by the white arrow.

[0012] Figure 3 c) is a SEM image taken by magnifying the four corners of a) image, and d) is a photo taken by magnifying the four corners of c) image again, showing the crack propagation state around the crack nucleation site where crack propagation begins. Summary of the Invention

[0013] The technical problem to be solved in this invention is to provide a dental implant in which the upper outer threaded section of the implant with shallow groove depth is extended to a certain position towards the lower side of the polygonal part inside the implant, thereby preventing transverse fracture caused by stress concentration near the polygonal part inside the implant.

[0014] Another technical problem to be solved by the present invention is to set a drilling interval under the polygonal part inside the implant to remove or reduce the possibility of the presence of crack nuclei, and based on the drilling interval, extend the upper outer threaded interval of the implant with shallow threaded groove depth to a certain position, thereby preventing fatigue fracture caused by stress concentration near the polygonal part inside the implant.

[0015] To address the aforementioned technical challenges, this invention provides a dental implant for forming an artificial tooth root by inserting alveolar bone tissue. From the lower end of the outer peripheral surface of the implant upwards to a certain interval, an outer lower end threaded section is formed, where a high-height thread is formed by a first planer. Furthermore, an outer upper end threaded section is formed above the outer lower end threaded section, where a low-height thread is formed by a second planer having a different processing surface shape and width than the first planer.

[0016] The thread pitch and thread crest width of each thread section processed by the first and second planers are all the same.

[0017] Here, the depth of the thread groove in the upper outer threaded section can gradually become shallower from the bottom to the top.

[0018] In addition, an unprocessed threaded section can be set in the upper external threaded section, extending from the top of the implant downwards through a certain interval.

[0019] At this point, the non-machined threaded area can be formed from the top of the implant downwards to a position of 0.2 to 0.3 mm.

[0020] In this case, a point can be set on the lower side of the non-machined thread area to change the inclination of the upper thread machining trajectory, i.e., the ending point, and the ending point can be located at a position 0.6 to 0.8 mm away from the uppermost end of the implant.

[0021] At this time, the planer that performs thread machining on the upper outer threaded section can move along a trajectory that is tilted at an angle of 23.5 to 26.5 degrees relative to the axis of the implant after completing the thread machining.

[0022] On the other hand, an internal groove is formed on the inner side of the upper end of the implant, which can be combined with the abutment for supporting the prosthesis, and the internal groove may include: an upper inclined portion located at the upper entrance of the implant, and having a circular cross-section with a shape that narrows towards the lower side; a polygonal portion formed on the lower side of the upper inclined portion, and having a polygonal cross-section; and a screw portion for abutment connection formed on the lower side of the polygonal portion, and having a thread with a diameter smaller than the circle of the polygon inscribed in the polygonal portion.

[0023] Here, when viewed from the upper end face of the implant, the outer upper threaded section can be configured to the lower side section 2 to 4 threads away from the lower end of the polygonal part.

[0024] In addition, the internal groove may also include a circular vertical portion with a circular cross-section, which is connected to the lower side of the polygonal portion.

[0025] Furthermore, the internal groove may also include a lower inclined portion, which is formed between the circular vertical portion and the base connecting screw portion, and the upper end is formed with the same diameter as the circular vertical portion, the lower end is formed with the same diameter as the base connecting screw portion, and is formed in a shape that gets narrower towards the lower inner diameter.

[0026] On the other hand, a circular drilling section with a diameter larger than that of the circle of the polygonal part circumscribed to the polygonal part can be formed between the lower end of the polygonal part and the upper end of the screw part for connecting the base.

[0027] In this case, when viewed from the upper end face of the implant, the outer upper threaded section can be configured to the lower section 2 to 4 threads away from the lower end of the drilling section.

[0028] In addition, the circular drilling section is formed by a first circular vertical portion and a circular portion with a certain curvature on the lower side of the first circular vertical portion, and the diameter of the first circular vertical portion can be formed to be larger than the diameter of the circumcircle of the polygonal portion.

[0029] In this case, the ratio of the diameter of the first circular vertical portion of the circular drilling section to the diameter of the circumscribed circle of the polygonal portion can be set to more than 100% and less than 115%.

[0030] Furthermore, the overall height along the axial direction of the circular drilling section can be set to 0.1–1.5 mm.

[0031] In addition, the planar shape of the polygonal part can be formed into any one of the following shapes: regular hexagon, regular octagon, and regular dodecagon.

[0032] According to an embodiment of the present invention having the above-described structure, the dental implant structure has an outer upper threaded section formed in the implant with a shallow threaded groove depth, and the outer upper threaded section is extended based on the upper end face of the implant, so that it is positioned in the lower section 2 to 4 threads away from the lower end of the polygonal portion. This ensures the thickness of the implant near the polygonal portion, increases the structural rigidity of this part, and thus has the effect of preventing transverse fracture caused by stress concentration near the polygonal portion.

[0033] Furthermore, according to another embodiment of the dental implant structure of the present invention, the upper end of the implant includes an upper inclined portion, a polygonal portion, and a screw portion for abutment connection. A circular drilling interval with a diameter larger than the diameter of the circle of the polygonal portion circumscribed in the polygonal portion is provided between the lower end of the polygonal portion and the upper end of the screw portion for abutment connection. An outer upper threaded interval is formed in the implant to make the thread groove depth shallow. When viewed with the upper end face of the implant as a reference, the outer upper threaded interval is positioned in the lower interval 2 to 4 threads away from the lower end of the drilling interval, thereby preventing stress concentration near the polygonal portion, ensuring the thickness of the implant, and increasing the structural rigidity of the corresponding part. Therefore, it has the effect of preventing fatigue fracture caused by stress concentration near the polygonal portion in the prior art.

[0034] In addition, when using a planer to process the screws on the upper part of the implant, a closed thread structure is formed on the upper part of the implant by changing the release position and release angle of the planer. This increases the thickness of the upper part of the implant, making the structure of the upper part of the implant more rigid, thereby preventing vertical fracture caused by fatigue failure at the upper part of the implant. Attached Figure Description

[0035] Figure 1 This is a photograph showing an example of a vertical fracture of an implant.

[0036] Figure 2 The photograph shows an example of a transverse fracture of the implant, and the diagram shows the state of stress generated at the lower corner of the abutment in the polygonal part of the implant.

[0037] Figure 3 It is a photograph showing the point where the vertical break of the implant begins from the lower corner of the polygonal part.

[0038] Figure 4 These are perspective and plan views illustrating the structure of a dental implant according to the present invention.

[0039] Figure 5 yes Figure 4 Front view.

[0040] Figure 6 This is a cross-sectional view showing the external thread structure of the implant according to the present invention.

[0041] Figure 7 This is a cross-sectional view specifically illustrating the internal structure of the implant according to the present invention.

[0042] Figure 8 This is an example diagram showing the movement trajectory of the planer during the machining of the upper external thread of the implant.

[0043] Figure 9It is a front view showing the location where the threaded non-machined area and the closed thread structure are formed at the upper end of the implant.

[0044] Figure 10 This is an example diagram comparing the thread width when machining external threads using a planer of the same shape and when machining external threads using planers of different shapes.

[0045] Figure 11 This is a diagram specifically illustrating the outer upper end threaded section with shallow groove depth in the implant of the present invention.

[0046] Figure 12 These are SEM images showing the polygonal portion of the prior art and the metal flow line at the lower corner of the polygonal portion according to the present invention.

[0047] Figure 13 It shows a photograph of a punching tool used for plastic forming of polygonal parts and a diagram of the punching process.

[0048] Figure 14 This is a diagram illustrating an embodiment of the implant polygonal portion processing method of the present invention.

[0049] Figure 15 This is a diagram illustrating yet another embodiment of the implant polygonal portion processing method of the present invention.

[0050] Figure 16 It shows the basis Figure 14 A diagram illustrating the formation process of the lower part of the polygonal vertical section in the processing method.

[0051] Figure 17 It shows the basis Figure 15 A diagram illustrating the formation process of the lower part of the polygonal vertical section in the processing method.

[0052] Figure 18 This document shows a plan view, a perspective view, and a cross-sectional view of a dental implant structure according to the present invention.

[0053] Figure 19 This is a front view of the dental implant structure according to the present invention.

[0054] Figure 20 This is a cross-sectional view showing the relationship between the internal structure and the external threaded structure of the implant according to the present invention.

[0055] Figure 21 This is a cross-sectional view specifically illustrating the external thread structure of the implant according to the present invention.

[0056] Figure 22 This is a cross-sectional view specifically illustrating the internal structure of the implant according to the present invention. Detailed Implementation

[0057] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art to which this invention pertains can easily implement it.

[0058] However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein. Furthermore, throughout the detailed description, portions indicated by the same reference numerals represent the same constituent elements.

[0059] Hereinafter, an embodiment of a dental implant according to the present invention will be described in detail with reference to the accompanying drawings.

[0060] Figure 4 These are perspective and plan views illustrating a dental implant structure according to an embodiment of the present invention. Figure 5 yes Figure 4 The front view. Additionally... Figure 6 This is a cross-sectional view showing the external threaded structure of the implant. Figure 7 It is a cross-sectional view that specifically shows the internal structure of the implant.

[0061] Reference Figures 4 to 7 According to an embodiment of the present invention, a dental implant 300 is a structure that is inserted into alveolar bone tissue and forms an artificial tooth root according to the rotation behavior of the central axis CL. A plurality of threads 212, 222 with the same (single) pitch are formed on the outer peripheral surface of the implant 300 of the present invention in the vertical direction.

[0062] In this case, in order to process threads 212 and 222 with the same pitch P on the outer peripheral surface of the implant 300, two cutters with different processing surface shapes are sequentially entered into the processing target surface of the implant material in the state before thread processing, and then moved from the lower end to the upper end of the implant to perform the processing operation, thereby forming two threaded sections 210 and 220 with different groove depths on the outer peripheral surface of the implant 300.

[0063] Here, when two threaded sections 210 and 220 with different threaded groove depths are formed on the outer peripheral surface of the implant 300, the first planer 230 (e.g., from the lower end of the implant 300 along the upper direction to a certain section) passes through the upper section. Figure 10 (b) A thread 222 with a deep groove depth (or a high thread height) is machined to form an outer lower thread section 220, and a thread 212 with a shallow groove depth (or a low thread height) is machined on the upper side of the outer lower thread section 220 by a second planer 240 to form an outer upper thread section 210.

[0064] In this case, such as Figure 6As shown, the groove depths D2 and D3 of the thread 212 formed in the outer upper thread section 210 are shallower than the groove depth D1 of the thread 222 formed in the outer lower thread section 220. In particular, the groove depths D2 and D3 (or thread height) of the thread 212 in the outer upper thread section 210 can be formed to gradually decrease in depth from the bottom to the top. In other words, in the outer upper thread section 210, the groove depth of the thread gradually decreases from the groove depth D2 of the bottom thread to the top, so that the groove depth D3 of the top thread is the shallowest.

[0065] For example, in the outer upper thread section 210, the highest lower thread 212 can be formed with a height of 0.22 mm, the highest thread 212 can be formed with a height of 0.12 mm, and the height of the thread decreases as it moves upward from the highest (0.22 mm) lower thread position to the upper thread position. Finally, the uppermost thread can be configured to form the lowest (0.12 mm) thread 212.

[0066] As described above, when the height (depth) of the thread 212 formed in the upper outer threaded section 210 of the implant 300 is formed in a structure that decreases towards the upper part, the implant 300 can not only be more firmly fixed to the compact bone region on the alveolar bone surface, but also the wall thickness of the upper part of the implant 300 is increased, which can ensure the rigidity of the upper part of the implant 300, thus preventing vertical fracture of the upper part of the implant.

[0067] On the other hand, an internal groove 100 of a specific shape with a certain depth is formed on the inner side of the upper end of the implant 300 so that an abutment for supporting the prosthesis can be attached. At this time, the internal groove 100 has a structure in which an upper inclined portion 110, a polygonal portion 120, a circular vertical portion 130, a lower inclined portion 140, and an abutment attachment screw portion 150 are arranged sequentially from the upper end inlet of the implant 300 downwards.

[0068] Specifically, the upper inclined portion 110, which is located at the upper entrance of the implant 300, has a circular cross-sectional shape and a shape structure in which the inner diameter width becomes narrower towards the lower side.

[0069] Furthermore, the polygonal portion 120, which is connected to the lower side of the upper inclined portion 110, has a hexagonal cross-sectional shape and is provided for fastening the connecting screwdriver (not shown) during the implantation of the implant 300. At this time, the polygonal portion 120 is presented in one embodiment shape, and in addition to the hexagonal shape, it can also be formed into various regular polygonal shapes such as octagonal and dodecagonal.

[0070] The circular vertical portion 130 is a portion with a circular cross-sectional shape connected to the lower side of the polygonal portion 120. The lower inclined portion 140 serves as the portion connecting the circular vertical portion 130 and the base mounting screw portion 150. Its upper end has the same diameter as the circular vertical portion 130, and its lower end has the same diameter as the base mounting screw portion 150. The lower inclined portion 140 is also formed with a structure that narrows towards the lower side of the inner radial direction.

[0071] The base engagement screw portion 150 is connected to the lower side of the lower inclined portion 140 and forms a base engagement thread 152 with a diameter smaller than the circle of the hexagonal portion inscribed in the polygonal portion 120.

[0072] On the other hand, such as Figure 8 As shown, on the upper side of the upper threaded section 210 of the implant 300 of the present invention, a thread-unprocessed section H with unprocessed threads is provided from the uppermost end of the implant 300 downwards over a certain interval. Preferably, the thread-unprocessed section H, as described above, extends from the uppermost end of the implant 300 downwards to a position of 0.2 to 0.3 mm (refer to...). Figure 9 Additionally, the area around the upper end face of the non-machined section H of the thread may be chamfered to a degree of 0.12mm.

[0073] This threaded unmachined section H is a section designed to ensure the strength and toughness of the upper part of the implant 300, which could cause vertical fracture. Since no threads are formed in the threaded unmachined section H, when the implant 300 is implanted into the alveolar bone, the threaded unmachined section H will not be inserted into the alveolar bone, but will be partially exposed outside the upper surface of the alveolar bone.

[0074] However, since the threaded unprocessed section H formed at the upper end of the implant 300 is a section with a very small length (0.2 to 0.3 mm) relative to the overall length of the implant 300, the support rigidity of the implant 300 in the alveolar bone will not decrease significantly even if it is not implanted into the alveolar bone until the threaded unprocessed section H is reached.

[0075] As described above, when an unprocessed threaded section H is formed at the upper end of the implant 300, when the implant 300 is implanted into the alveolar bone, the thickness of the upper end of the implant 300 can be ensured to reach a certain level without significantly reducing the supporting force of the implant 300 in the alveolar bone, thus increasing the structural rigidity of the upper end of the implant 300.

[0076] On the other hand, in order to form two threaded sections 210, 220 with different threaded groove depths (or threaded heights) on the outer peripheral surface portion of the implant 300 of the present invention, and as Figure 10As shown in b), two planer blades 230 and 240 with different machining surface shapes are used to perform thread machining on the machining surface of the implant parent material.

[0077] In typical implant threading operations, the implant material is rotated while a planer enters the lower end of the object to be processed on the implant and moves upward along a predetermined trajectory to perform threading. In this case, the thread height can be adjusted by adjusting the depth of the planer into the object to be processed on the implant material.

[0078] In the implant 300 of the present invention, when the lower outer threaded section 220 is formed, the first planer 230 enters the implant mother material to perform thread 222 processing with a deep thread groove (or high thread height), and when the thread 222 processing is completed by the first planer 230, the first planer 230 is replaced by the second planer 240 to perform thread 212 processing of the upper outer threaded section 210.

[0079] In this case, as mentioned earlier, since an unprocessed threaded section H is formed from the top of the implant 300 downwards to a certain depth (0.2-0.3 mm), the processing of the outer upper thread of the implant 300 by the second planer 240 will not proceed to the top of the implant 300. Instead, at a certain distance downwards from the top of the implant 300, the inclination of the processing trajectory of the second planer 240 is significantly changed to complete the thread processing, thereby achieving the desired result. Figure 4 and Figure 5 As shown, the upper outer part of the implant 300 can be formed as a closed thread structure.

[0080] Figure 8 This is an example diagram showing the movement trajectory of the planer blade when machining the external upper thread of the implant 300. Figure 9 It is a front view showing the location of the threaded non-machined area H and the closed thread structure formed at the upper end of the implant 300.

[0081] like Figure 8 and Figure 9 As shown, in order to form a closed thread structure on the upper outer end of the implant 300, when the upper outer thread is processed by the second planer 240, it moves along the first moving trajectory P1, and the second planer 240, which performs the thread processing operation, moves to a specific point on the second moving trajectory P2 after leaving the first moving trajectory P1.

[0082] In other words, when the second planer 240, which performs thread 212 machining, moves along the first moving trajectory P1 and the point where it leaves the first moving trajectory P1 (or the starting point of the second moving trajectory), i.e. the ending point EP, is set below the non-machined thread section H, a closed thread structure can be formed at the upper outer part of the implant 300.

[0083] To explain in more detail, such as Figure 8 As shown, when processing the upper outer thread of the implant 300, after the second planer 240 enters the lower end of the processing object surface of the implant 300, it moves upward along the first moving trajectory P1 while performing the thread 212 processing operation. When the thread 212 processing is completed, the second planer 240 leaves the first moving trajectory P1 and moves again along the second moving trajectory P2.

[0084] At this time, in order to perform the external upper thread machining operation, the first movement trajectory P1 of the second planer 240 is not parallel to the central axis of the implant 300, i.e., the axis CL, but is inclined at a first angle θ1 relative to the axis CL. Therefore, the external upper thread section 210 of the implant 300 has a shape where the diameter decreases towards the bottom.

[0085] Furthermore, after the second planer 240 moves along the first moving trajectory P1 and performs threading, the second moving trajectory P2 after leaving the end point EP at the upper end of the implant 300 forms an inclined second angle θ2 relative to the axis CL of the implant 300.

[0086] At this time, when the second angle θ2 between the second moving trajectory P2 and the axis CL is formed to be a sufficiently large angle compared to the first angle θ1 between the first moving trajectory P1 and the axis CL, the second planer 240, after performing thread processing along the first moving trajectory P1, disengages from the end point EP and moves along the second moving trajectory P2 again to a specific point, and then no longer performs thread processing. Therefore, in the uppermost threaded section 210 of the implant 300, the thread at the uppermost end can be formed into a closed thread structure that is blocked below the non-processed threaded section H without passing through the upper end face of the implant 300.

[0087] Preferably, in this case, the end point EP of the thread 212 machining completed by the second planer 240 is set at a location K 0.6 to 0.8 mm from the uppermost end of the implant 300. Here, the end point EP refers to the location of the center of the second planer 240 when it leaves the first moving trajectory P2.

[0088] Moreover, preferably, the second movement trajectory P2 of the second planer 240 after completing the threading is set at an angle of 23.5 to 26.5 degrees inclined relative to the axis CL of the implant 300.

[0089] As described above, when the threading operation is performed on the upper outer surface of the implant 300, the second planer 240 initially enters the implant 300 and moves along the first moving trajectory P1 to perform threading. Then, at a position 0.6 to 0.8 mm below the uppermost surface of the implant 300, the second planer 240 disengages from the object surface at an angle of 23.5 to 26.5 degrees and moves along the second moving trajectory P2, thereby forming a closed thread structure in the upper part of the implant 300.

[0090] As described above, when processing the upper external thread of the implant 300 using the second planer 240, by changing the disengagement position and disengagement angle of the second planer 240, a closed thread structure, i.e. a closed thread structure, can be formed at the upper end of the implant 300. Therefore, by increasing the thickness of the upper end of the implant 300, the structural rigidity of the upper end of the implant 300 can be increased, thereby preventing frequent vertical fractures at the upper end of the implant 300.

[0091] On the other hand, in order to machine threads 212 and 222 with the same pitch P on the outer surface of the implant 300, it is necessary to have different shapes on the end surfaces of the first planer 230 that performs the lower outer thread machining of the implant 300 and the second planer 240 that performs the upper outer thread machining.

[0092] Figure 10 The diagram illustrates the thread groove depth and thread width when using a planer of the same shape to machine external threads on an implant and when using two planers of different shapes to machine external threads.

[0093] first, Figure 10 In case (a) when using a planer of the same shape to perform machining of the lower outer thread 222 and the upper outer thread 212, when a planer with the same end machining surface shape is used, the thread crest width of the upper outer thread 212 with a shallower groove depth will become wider. Therefore, if the implant 300 is implanted into the alveolar bone, a relatively large torque is required, and the implantation operation of the implant 300 is difficult, which may also lead to damage to the alveolar bone.

[0094] On the contrary, such as Figure 10As shown in (b), in this invention, the first planer 230 and the second planer 240, which process the outer lower thread 222 and the outer upper thread 212, have different end face shapes and widths to perform thread processing operations. Therefore, although the groove depths of the threads 212 and 222 formed in the outer upper thread section 210 and the outer lower thread section 220 of the implant 300 are different, the pitch P of each thread is the same, and a thread structure with the same thread crest width can be formed. As described above, when the thread crest width is narrow, the area of ​​the thread groove is increased compared to the prior art, thus achieving advantageous effects even during sandblasting or coating processes.

[0095] on the other hand, Figure 11 Specifically, the location where the outer upper threaded section 210 is formed in the implant 300 of the present invention is shown.

[0096] like Figure 11 As shown, when the implant 300 of the present invention forms an outer upper thread section 210 with a low thread height 212 (or groove depth), the lower end of the outer upper thread section 210 can be formed as a position that descends 2 to 4 threads 212 from the bottom surface of the lower end of the polygonal portion 120 inside the implant 300.

[0097] As described above, when the lowermost end of the outer upper threaded section 210 is formed in the form of 2 to 4 threads 212 below the lower bottom surface of the inner polygonal portion 120 located at a distance from the implant 300, when punching is performed to form the polygonal portion 120 structure in the inner groove 100 of the implant 300, the thickness of the corresponding part can be indirectly increased by forming a shallow thread 212 depth. This overcomes the disadvantage that geometrically uneven points are generated at the lower corner of the polygonal portion, which makes the area near the polygonal portion 120 the starting point of fatigue failure cracks, as in the prior art. Therefore, the transverse fracture phenomenon that occurs near the polygonal portion, as in the prior art, can be prevented.

[0098] On the other hand, the following will describe a dental implant structure according to yet another embodiment of the present invention. In particular, the following will describe in detail the process of proposing the present invention with reference to the accompanying drawings, and will also describe in detail the corresponding preferred embodiments.

[0099] Figure 12 As an example of SEM photographs illustrating the necessity and application results of the present invention, a) the photograph shows the "metal flow line" at the lower corner of the polygonal portion produced according to the prior art.

[0100] pass Figure 12Photograph a) confirms that in the polygonal portion manufactured using existing technology, the lower corner portion of the polygonal portion (the white portion in the photograph represents the implant portion, the lower part of the segmented portion, i.e., the lower left end is divided into the lower corner portion of the polygonal portion) experiences severe plastic deformation, and it is evident that a defective crack nucleus exists in this portion. Conversely, photograph b) shows the portion marked with dashed lines removed using the drilling interval described later. It is evident that by removing the plastically deformed portion, the "metal flow lines" of the original base material state, which are uniform throughout, are preserved, thereby significantly reducing the possibility of crack nuclei. Photograph c) shows the case where the drilling interval in this invention is formed using another method (processing the drilling interval first and then processing the polygonal portion). It is evident that there is no plastically deformed portion as in photo a), and the metal flow lines of the original base material state, which are uniform throughout, remain unchanged, significantly reducing the possibility of crack nuclei.

[0101] In the prior art, when examining the existing manufacturing process of polygonal parts to determine the cause of problems like those shown in photograph a), in order to process the polygonal parts, such as... Figure 13 As shown in a), a punching tool with a rectangular cross-sectional shape at its end is used, such as Figure 13 As shown in b), after the polygonal part is machined with an inclined surface of a circular cross-section for placing the abutment by the internal groove of the circular rod used as the implant material, the punching tool 10 is forcefully struck downwards. In the next step, the punching tool is rotated at a 60-degree angle (indicated by a dashed line) and then struck again. In the next step, the punching tool is rotated at a 60-degree angle again and then struck (indicated by a dotted line). Through the above process, the polygonal part with hexagonal corners is finally completed.

[0102] In addition, as mentioned above, during the process of forcefully striking with a punching tool with four corners, the base material in contact with the corner of the punching tool gathers downwards, and during the plastic deformation process, residual stress is generated in the implant. Ideally, this residual stress is used as compressive residual stress, and during fatigue fracture behavior, compressive force is applied around the crack initiation point, thereby expecting to have the effect of inhibiting fatigue fracture propagation.

[0103] However, in reality, the corner portion of the punching tool 10 cuts the side of the base material while simultaneously compressing and deforming it. Therefore, uniform compressive residual stress cannot usually be expected at the corners of the polygonal portion during the desired plastic processing. Furthermore, it can be determined that a portion of the base material that falls off the processed surface as observed from the microscopic perspective ultimately exists as a crack nucleus. In addition, there are multiple irregularly distributed crack nuclei formed by the tiny detachment of the base material on the left side of the polygonal portion, which become the cause of fatigue fracture.

[0104] Therefore, in this invention, which is completely different from the existing polygonal part processing technology, after the polygonal part is formed by punching, the part corresponding to the left side of the polygonal part is drilled and removed by machine tool with a diameter greater than the length from the geometric center point of the punching tool to the corner. Alternatively, the part corresponding to the left side of the polygonal part is pre-processed and removed by machine tool with a diameter equal to or slightly greater than the length from the geometric center point of the punching tool to the corner. Then, by performing a punching process, the remaining space for the parent material pushed in by the punching tool to be removed is ensured in advance, thereby significantly reducing the possibility of severe plastic deformation and crack nucleation on the left side of the polygonal part.

[0105] Therefore, in this invention, by means of... Figure 14 and Figure 15 The method shown is for manufacturing the polygonal portion of the implant.

[0106] Figure 14 As an example, a process for manufacturing an implant is shown, comprising the following steps: cutting the workpiece, i.e., a rod, to a certain length; machining the implant's external shape; machining the implant's internal shape, machining an internal groove on the upper end face to allow for the integration of an abutment for supporting the prosthesis within the implant, wherein the cross-section of the internal groove at the upper end face entrance is circular, and machining an upper inclined portion with a narrower inner diameter towards the lower side, and machining a hole for screws below it; machining a polygonal portion towards the machined upper inclined portion using a punching tool; machining a drilling section in the lower part of the bottom portion including the machined polygonal portion; and machining an internal screw portion in the hole for screws.

[0107] Figure 14 The core of the polygonal part processing method is that during the punching process to form the polygonal part, the area that causes severe plastic deformation of the base material is removed as a drilling zone. The bottom part of the polygonal part formed by punching is included between the lower end of the polygonal part and the upper end of the screw part for the base assembly, and the area with a diameter larger than the diameter of the circle of the polygonal part circumscribed in the polygonal part is removed as a circular drilling zone.

[0108] More in detail, such as Figure 16 As shown in a) and b), the lower part of the polygonal portion formed by the punching process includes the bottom part of the polygonal portion, which is removed by a drilling tool to form a drilling section. The drilling section can be processed into a first vertical portion 431 and a circular portion 432, and the radius of the drilling section should be set to be larger than the radius of the circumcircle of the polygonal portion.

[0109] As described above, by machining the drilled area, the fatigue failure characteristics of the lower part of the polygonal portion according to the present invention can be significantly improved. Figure 16b) shows the state of the polygonal portion after punching, and the figure also shows the case where the workpiece at the corner of the polygonal portion is plastically deformed downwards and forced in by a punching tool that enters from above, as shown. Figure 12 As confirmed in a), this indicates a region showing severe deformation of the metal flow lines and a high probability of crack nucleation, but as Figure 16 b) As shown in the right figure, according to the method of the present invention, the processed portion, including the bottom part of the problematic polygonal portion, is removed by drilling, thus eliminating the problems of the prior art previously observed.

[0110] Figure 15 As another embodiment, a process for manufacturing an implant is shown, comprising the following steps: cutting the workpiece, i.e., the rod, to a certain length; machining the implant's external shape; machining the implant's internal shape, more specifically, machining an internal groove on the upper end face to allow for the integration of an abutment for supporting the prosthesis within the implant, the internal groove having a circular cross-section at its upper end face entrance, and machining an upper inclined portion with a narrower inner diameter towards the lower side, a drilled section having a diameter that expands radially from the end of the upper inclined portion, and a hole for machining screws downward therefrom; machining a polygonal portion towards the machined upper inclined portion using a punching tool; and machining an internal screw portion in the hole for machining screws.

[0111] Figure 15 The core of the polygonal part processing method is to first process the drilling area to avoid severe plastic deformation of the base material, and then perform punching to form the polygonal part. Before the polygonal part punching process, a circular drilling area with a diameter larger than the diameter of the circle of the polygonal part circumscribed in the polygonal part is processed and set between the lower end of the polygonal part and the upper end of the base joint screw part.

[0112] More in detail, such as Figure 17 As shown in a), a drilling section is machined at the lower end of the inclined portion. The drilling section can be machined into a first circular vertical portion 431 and a circular portion 432 with a certain curvature on the lower side of the first circular vertical portion. The radius of the drilling section should be set to be greater than the radius of the circumcircle of the polygonal portion.

[0113] As described above, by setting the drilling interval, the state of the polygonal part punching process according to the present invention is completely different from the polygonal part punching process of the prior art, and as... Figure 17 As shown in b), according to the method of the present invention, since the processed part is processed by the punching tool into a shape that cuts the base material such as a knife or scissors, or the side of the processed part cannot be gathered to the lower corner (even if it is gathered to the corner, it can be easily removed by conventional deburring operations), the problems of the prior art can be eliminated.

[0114] This invention relates to a dental implant having a drilled section formed by the method described above. Figure 18 These figures illustrate a) a plan view, b) an external perspective view, and c) an internal cross-sectional perspective view of the dental implant structure according to the present invention. Figure 19 for Figure 18 Front view. Figure 20 This is a cross-sectional view showing the relationship between the internal structure and the external threaded structure of the implant according to the present invention. Figure 21 This is a cross-sectional view showing the detailed structure of the external threads of the implant according to the present invention. Figure 22 This is a cross-sectional view specifically illustrating the internal structure of the implant according to the present invention.

[0115] Reference Figures 18 to 22 According to the present invention, a dental implant is a dental implant that forms an artificial tooth root by being inserted into alveolar bone tissue according to a rotational action relative to the axis CL. A single-pitch thread P is formed on the outer peripheral surface of the implant. An outer lower end thread section 520 with a deep groove 522 is formed from the lower end of the implant upwards to a certain interval. An outer upper end thread section 510 with a shallow groove 512 is formed above the outer lower end thread section. An internal groove 400 for engaging an abutment for supporting a prosthesis is formed on the inner side of the upper end of the implant. The internal groove 400 includes an upper inclined portion 410 located at the upper end inlet of the implant and transversely... The cross-section is circular, with the inner diameter narrowing towards the bottom; a polygonal portion 420 is formed on the lower side of the upper inclined portion, and its cross-sectional shape is polygonal; a base-connecting screw portion 460 is formed on the lower side of the polygonal portion, and has a thread with a diameter smaller than the circle of the polygonal portion inscribed in the polygonal portion; a circular drilling interval 430 is provided between the lower end of the polygonal portion 420 and the upper end of the base-connecting screw portion 460, which has a diameter larger than the circle of the polygonal portion inscribed in the polygonal portion; and when viewed with reference to the upper end face of the implant, the outer upper thread interval 510 is positioned to the lower interval 2 to 4 threads away from the bottom surface of the drilling interval 430.

[0116] like Figure 20 As shown, when the implant of the present invention forms an outer upper threaded section 510 with a low thread height 512 (or groove depth), the lower end of the outer upper threaded section 510 is formed at the lower bottom surface of the drilled section 430 inside the implant. More specifically, the drilled section 430 extends from the bottom surface of the circular portion 432 to the lower side position approximately 2 to 4 threads.

[0117] As described above, when the lowermost end of the outer upper threaded section 510 is configured to be located 2 to 4 threads 512 below the lower bottom surface of the drilling section 430, in order to eliminate the severe plastic deformation and crack nucleation that occur during the formation of the polygonal portion 420 in the internal groove 400 of the implant, it is possible to ensure that the drilling section 430 of the present invention and the thick outer upper threaded section 510 of the implant are reinforced to the lower side of the drilling section 430, thus more effectively preventing fatigue fracture near the lower end of the polygonal portion 420.

[0118] Additionally, as an embodiment of the present invention, in order to machine threads 512 and 522 with a single pitch P on the peripheral surface of the implant, as described above... Figure 10 As shown in b), before the implant material is threaded, the surface to be processed enters two planers with different surface shapes and moves from the lower end to the upper end of the implant to perform the processing operation, thereby forming two threaded sections 510 and 520 with different groove depths on the outer peripheral surface of the implant.

[0119] In other words, from the lower end of the implant along the upper direction to a certain interval, a thread 522 with a deep groove depth (or high thread height) is machined by the first planer 230 to form an outer lower thread interval 520, and an outer upper thread interval 510 is formed by machining a thread 512 with a shallow groove depth (or low thread height) on the upper side of the outer lower thread interval 520 by the second planer 240.

[0120] In this case, such as Figure 21 As shown, the groove depths D2 and D3 of the thread 512 formed in the outer upper thread section 510 are lower than the groove depth D1 of the thread 522 formed in the outer lower thread section 520. Furthermore, the groove depths D2 and D3 (or thread height) of the thread 512 in the outer upper thread section 510 can be formed such that they gradually decrease from the bottom to the top. In other words, in the outer upper thread section 510, the groove depth of the thread gradually decreases from the groove depth D2 of the lowest thread upwards, thereby making the groove depth D3 of the highest thread the shallowest.

[0121] As described above, when the height (depth) of the thread 512 formed in the upper external threaded section 510 of the implant is formed into a structure that gradually decreases upward, the implant can not only be more firmly fixed to the compact bone region on the alveolar bone surface, but also the wall thickness of the upper part of the implant is increased, which can ensure the rigidity of the upper part of the implant, and thus also increase the toughness against vertical fractures occurring at the upper end of the implant.

[0122] On the other hand, the circular drilling interval 430 formed inside the implant is a circular interval with a diameter larger than the diameter of the circle of the polygonal portion. Preferably, it is formed by a first circular vertical portion 431 and a circular portion 432 with a certain curvature on the lower side of the first circular vertical portion, and the diameter of the first circular vertical portion can be larger than the diameter of the circumscribed circle of the polygonal portion.

[0123] In a preferred embodiment, the ratio of the diameter of the first circular vertical portion 431 of the circular drilling section 430 to the diameter of the circumscribed circle of the polygonal portion can reach 100% or more and 115% or less.

[0124] In addition, the overall height h1 along the axis CL of the circular drilling section 430 can be set to 0.1 to 1.5 mm.

[0125] In other words, preferably, Figure 22 The diameter d1 of the first circular vertical portion 431 of the circular drilling section 430 shown is 100% to 115% of the diameter dp of the circumscribed circle of the polygonal portion. Preferably, the overall height h1 along the axis CL of the circular drilling section 430 is 0.1 to 1.5 mm.

[0126] Furthermore, the polygonal portion 420, which is connected to the lower side of the upper inclined portion 410, has a polygonal cross-sectional shape and is used to fasten a screwdriver (not shown) during implantation. In this case, the polygonal portion 420 is shown as a regular hexagon in cross-sectional shape, but in addition to a regular hexagon, it can also be formed into various regular polygonal shapes such as a regular octagon or a regular dodecagon.

[0127] When the polygonal part is increased from a regular hexagon to a regular octagon, regular dodecagon, etc., the range of directions for fastening the connecting abutment will increase to 6->8->12. The advantage is that the connecting abutment can be fastened in a more accurate direction according to the patient.

[0128] Next, the second circular vertical portion 440 is a portion with a circular cross-sectional shape connected to the lower side of the drilling section 430, and the inner inclined portion 450 serves as the portion connecting the second circular vertical portion 440 and the base mounting screw portion 460, with its upper end having the same diameter as the second circular vertical portion 440 and its lower end having the same diameter as the base mounting screw portion 460. As described above, the inner inclined portion 450 is also formed with a structure that gradually narrows towards the lower inner diameter.

[0129] Furthermore, the dental implant of the present invention can be used in conjunction with the aforementioned Figure 9Similarly, an unprocessed threaded section H is provided on the upper side of the outer upper threaded section 510, extending from the uppermost end of the implant downwards over a certain distance. Preferably, the unprocessed threaded section H, as described above, extends from the uppermost end of the implant downwards to a position of 0.2–0.3 mm (refer to...). Figure 9 Additionally, the area around the upper end face of the non-machined section H of the thread may be chamfered to a degree of 0.12mm.

[0130] This thread-free non-machined section H is a section designed to further ensure the strength and toughness of the upper portion of the implant, which could cause vertical fracture.

[0131] On the other hand, the implant of the present invention, in order to form two threaded sections 510, 520 with different threaded groove depths (or threaded heights) on its outer peripheral surface portion, as described above... Figure 10 As shown in b), two planer blades 230 and 240 with different processing surface shapes can be used to perform thread processing on the processing surface of the implant parent material.

[0132] In other words, when the lower outer threaded section 520 is formed, the first planer 230 enters the implant material to perform thread 522 machining with a deep thread groove depth (or high thread height), and when the thread 522 machining is completed by the first planer 230, the first planer 230 is replaced by the second planer 240 to perform thread 512 machining of the upper outer threaded section 510.

[0133] Additionally, as mentioned earlier, in order to form an unprocessed threaded section H from the top of the implant downwards to a certain depth (0.2–0.3 mm), as described above... Figure 8 As shown, the machining of the outer upper thread of the implant by the second planer 240 does not proceed to the top part of the implant, but to a point a certain distance away from the top of the implant, so that the inclination of the machining trajectory of the second planer 240 is increased to complete the thread machining, thereby forming a closed thread structure on the outer upper part of the implant.

[0134] In other words, as mentioned above Figure 8 As shown, in order to form a closed thread structure on the upper outer end of the implant, when the upper outer thread is processed by the second planer 240, it moves along the first moving trajectory P1, and the second planer 240, which performs the thread processing operation, moves to a specific point on the second moving trajectory P2 after leaving the first moving trajectory P1. When it moves along the first moving trajectory P1 and the location where the second planer 240, which performs the thread processing operation, leaves the first moving trajectory P1 (or the starting point of the second moving trajectory), i.e., the end point EP, is set below the non-processing section H of the thread, a closed thread structure can be formed on the upper outer end of the implant.

[0135] In this case, preferably, the end point EP of the thread 512 machining completed by the second planer 240 is set to a location 0.6 to 0.8 mm from the uppermost end of the implant. Here, the end point EP refers to the position of the center point of the end of the second planer 240 when it leaves the first moving trajectory P2.

[0136] Moreover, preferably, the second movement trajectory P2 of the second blade 240 after the first movement trajectory P1 is set at an angle of 23.5 to 26.5 degrees relative to the axis of the implant.

[0137] As mentioned above, when processing the upper external thread of the implant using the second planer 240, by changing the disengagement position and disengagement angle of the second planer 240, a closed thread structure can be formed at the upper end of the implant. Therefore, the structural rigidity of the upper end of the implant can be increased by increasing the thickness of the upper end of the implant, thereby strengthening the upper end of the implant which is prone to vertical fracture and preventing fatigue fracture.

[0138] On the other hand, preferably, in order to process threads 512, 522 with the same pitch P on the outer surface of the implant, the shapes of the end processing surfaces of the first planer 230, which performs the lower outer end thread processing of the implant, and the second planer 240, which performs the upper outer end thread processing, are different.

[0139] As mentioned above, Figure 10 The invention illustrates the conventional method of machining external threads on implants using a planer of the same shape, and the thread groove depth and thread width of the present invention using planers of different shapes.

[0140] first, Figure 10 In the conventional case of using the same planer to perform machining of the lower outer thread 522 and the upper outer thread 512, since the planer with the same end machining surface shape is used at the upper and lower ends, the thread crest width of the lower outer thread 522 with a deeper groove depth is not a problem. However, the thread crest width of the upper outer thread 512 with a shallower groove depth will suddenly widen. Therefore, when the implant is inserted into the alveolar bone, a relatively large torque is required at the corresponding boundary, which may lead to unsuccessful implantation and damage to the alveolar bone.

[0141] On the contrary, such as Figure 10As shown in (b), in this invention, thread machining is performed with the end face shapes and widths of the first planer 230 and the second planer 240 for machining the outer lower thread 522 and the outer upper thread 512 being different. This allows for the formation of thread structures where, although the groove depths of the respective threads 512 and 522 formed in the outer upper thread section 510 and the outer lower thread section 520 of the implant are different, the same thread pitch P and the same thread crest width can be achieved. As described above, when the thread crest width is narrow, the area of ​​the thread groove is increased compared to the prior art, thus providing a favorable effect even during sandblasting or coating processes.

[0142] While the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited to these specific embodiments. Those skilled in the art can make appropriate modifications within the scope of the patent claims of the present invention.

Claims

1. A dental implant as a dental implant for forming an artificial tooth root by being inserted into alveolar bone tissue, characterized in that, an outer lower end thread section in which a high-height thread is formed by a first shaver is formed from a lower end of an outer peripheral surface of the implant to a certain section on the upper side, and an outer upper end thread section in which a low-height thread is formed by a second shaver having a different processing surface shape and width from the first shaver is formed on the upper side of the outer lower end thread section, a thread pitch and a thread top width of the thread of each thread section processed by the first shaver and the second shaver are formed to be the same throughout, an inner groove which can be combined with an abutment for supporting a prosthesis is formed on the inner side of an upper end portion of the implant, the inner groove includes an upper side inclined portion which is located at an upper end entrance portion of the implant and has a circular cross section and a shape in which an inner diameter becomes narrower toward the lower side, a polygonal portion which is formed on the lower side of the upper side inclined portion and has a polygonal cross-sectional shape, and an abutment combination screw portion which is formed on the lower side of the polygonal portion and has a thread having a diameter smaller than a diameter of a circle inscribed in a polygon of the polygonal portion, a circular drill hole section having a diameter larger than a diameter of a circle circumscribed to the polygon of the polygonal portion is formed between a lower end of the polygonal portion and an upper end of the abutment combination screw portion, the circular drill hole section is formed before a punch hole forming the polygonal portion is formed.

2. The dental implant according to claim 1, characterized in that, a thread groove depth of the outer upper end thread section is gradually shallower from a lower portion to an upper portion.

3. The dental implant according to claim 1, characterized in that, a thread non-processing section in which a non-processed thread is provided is provided from the uppermost end of the implant to a certain section on the lower side in the outer upper end thread section.

4. The dental implant according to claim 3, characterized in that, the thread non-processing section is formed to a position of 0.2 to 0.3 mm on the lower side from the uppermost end of the implant.

5. The dental implant according to claim 3, characterized in that, a point at which an inclination of a processing track of the outer upper end thread is changed, that is, an end point, is provided on the lower side of the thread non-processing section, and the end point is located at a position of 0.6 to 0.8 mm from the uppermost end of the implant.

6. The dental implant according to claim 5, characterized in that, a moving track of a shaver which performs thread processing of the outer upper end thread section moves at an angle of 23.5 to 26.5 degrees with respect to an axis of the implant after leaving the end point position after completing the thread processing.

7. The dental implant according to claim 1, characterized in that, when viewed with reference to an upper end surface of the implant, the outer upper end thread section is disposed to a lower side section of 2 to 4 threads from a lower end of the polygonal portion.

8. The dental implant according to claim 1, characterized in that Further includes: a circular vertical portion which has a circular cross section and is connected and formed on the lower side of the polygonal portion.

9. Dental implant according to claim 8, characterized in that Further includes: a lower side inclined portion which is connected and formed between the circular vertical portion and the abutment combination screw portion, and has the same diameter as the circular vertical portion at an upper end, the same diameter as the abutment combination screw portion at a lower end, and is formed in a shape in which an inner diameter becomes narrower toward the lower side.

10. The dental implant according to claim 1, wherein the outer upper end thread section is disposed to a lower section 2 to 4 threads from the lower end of the bore section when viewed from the upper end surface of the implant.

11. The dental implant according to claim 1, wherein the circular bore section is formed by a first circular vertical portion and a circular portion having a curvature below the first circular vertical portion, and the diameter of the first circular vertical portion is larger than the diameter of the circumscribed circle of the polygonal portion.

12. The dental implant according to claim 11, wherein the ratio of the diameter of the first circular vertical portion of the circular bore section to the diameter of the circumscribed circle of the polygonal portion is 100% or more and 115% or less.

13. The implant according to claim 1, wherein the overall height in the axial direction of the circular bore section is set to 0.1 to 1.5 mm.

14. The dental implant according to claim 1, wherein the planar shape of the polygonal portion is any one of a regular hexagon, a regular octagon, and a regular dodecagon.

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