Method for treating surface of dental implant and dental implant with surface treated by same

Abstract

A method of treating a surface of a dental implant to impart roughness to the surface is disclosed. The dental implant surface treatment method according to the present invention may comprise: a first surface treatment step for forming regular-pattern grooves in all or a part of the implant surface by means of a laser; and a second surface treatment step of imparting roughness to the grooves and the peripheries of the grooves by acid etching, the first surface treatment step including: a first laser treatment step of processing a plurality of first grooves that are continuous in a first direction and spaced apart in a second direction; and a second laser processing step of processing a plurality of second grooves that are continuous in the second direction and spaced apart in the first direction so as to form a depression at each intersection of the first grooves and the second grooves.

Description

Technical Field

[0001] The present invention relates to a method for treating the surface of a dental implant and a dental implant having the surface treated by the method. Background Art

[0002] Dental implants originally meant replacements for lost human tissue, but in dentistry they refer to artificially created teeth. This implant procedure is widely used as a replacement procedure to restore or reconstruct the function of natural teeth when they are lost or have reduced function.

[0003] In dental implant surgery, the key is how well the implant integrates with the bone, creating a secure bond. This is known as osseointegration, and excellent osseointegration allows the implant to be fixed to the bone, achieving initial stability and ultimately creating a permanent bond between the implant and bone.

[0004] Osseointegration properties are closely related to the surface area of a dental implant. This is because a larger surface area allows for greater osseointegration, which in turn increases the fixation force. In the field of dental implants, it is common practice to increase the surface area by applying roughness to the surface of dental implants. Known surface treatment methods for roughening dental implant surfaces include sandblasting and acid etching.

[0005] Sandblasting is a method of applying roughness to the machined surface of a dental implant by spraying amorphous ceramic powders such as Al2O3 and TiO2 at high pressure. However, sandblasting alone can leave residues or burrs on the surface of the dental implant, which can become a problem. Therefore, etching with acid is performed as a post-processing method to remove surface residues and burrs and to impart a fine roughness.

[0006] However, when the surface of a dental implant is treated by sandblasting to impart roughness, although this has the effect of increasing the surface area of the dental implant, Figure 1 As shown in the example of FIG, the morphology of the implant surface treated by the high-pressure sprayed amorphous ceramic powder is irregular, and as shown in FIG. Figure 2 As shown, the design of threads or cutting edges on the surface of the machined dental implant may be changed.

[0007] In particular, when the surface of a dental implant has an irregular morphology, integration deviations may occur at different locations during the bone integration process. Design changes such as the threads or cutting edges of the dental implant surface performed by sandblasting may exert excessive pressure on the surrounding alveolar bone during implantation or affect the self-tapping function.

[0008] Prior art literature

[0009] Patent Document 1: Korean Registered Utility Model No. 20-0386621 (published on June 2, 2005) Summary of the Invention

[0010] Technical issues

[0011] The technical problem to be solved by the present invention is to provide a dental implant surface treatment method that can form a regular pattern of surface morphology on the surface of the dental implant, thereby eliminating the influence of the surface treatment on the design of the dental implant and achieving stable bone integration performance without deviation in different parts, and a dental implant surface treated by this method.

[0012] Solutions to the Problem

[0013] As a solution to the problem, according to one embodiment, a method for treating the surface of a dental implant to impart roughness to the surface may be provided. The method comprises: a first surface treatment step of forming grooves in a regular pattern on all or a portion of the implant surface using a laser; and a second surface treatment step of imparting roughness to the grooves and their peripheries by acid etching, wherein the first surface treatment step comprises: a first laser treatment step of processing a plurality of first grooves that are continuous in a first direction and spaced apart in a second direction; and a second laser treatment step of processing a plurality of second grooves that are continuous in the second direction and spaced apart in the first direction, thereby forming a crater at each intersection of the first and second grooves.

[0014] In one embodiment of the present invention, the first direction may be a circumferential direction of the implant, and the second direction may be a height direction of the implant intersecting with the first direction.

[0015] In one embodiment of the present invention, the width w1 and depth d1 of the first groove may be formed to be the same as the width w2 and depth d2 of the second groove. Preferably, the widths w1 and w2 of the first groove and the second groove may be 5 μm to 30 μm, and the depths d1 and d2 may be 5 μm to 10 μm.

[0016] In one embodiment of the present invention, a distance D1 between a first trench and another adjacent first trench in the second direction may be 5 μm to 20 μm, and a distance D2 between a second trench and another adjacent second trench in the first direction may be 5 μm to 20 μm.

[0017] In one embodiment of the present invention, acid etching may be performed on the implant for 5 to 10 minutes in the second surface treatment step.

[0018] As a solution to the problem, according to another embodiment, a dental implant can be provided. The dental implant is implanted in the alveolar bone to form an artificial tooth root, comprising: an internal groove formed at a specific depth from the upper end surface and combined with an abutment for supporting a restoration; and an external surface formed with external threads for implantation into the alveolar bone, wherein all or a portion of the external surface can be surface-treated by the surface treatment method of one embodiment.

[0019] In another embodiment of the present invention, the external thread may include: an external lower thread section, formed from the lower end of the implant toward the upper side, at a first height with a first depth; and an external upper thread section, formed toward the top of the external lower thread section, at a second height with a second depth lower than the first depth, wherein, compared to the external lower thread section, the external upper thread section may be a low-density structure of a crater formed by surface treatment.

[0020] Effects of the Invention

[0021] According to an embodiment of the present invention, a dental implant surface treatment method imparts roughness to the implant surface by utilizing laser precision machining. This can prevent accidental damage or alteration to the design of threads or cutting edges on the implant surface during the surface treatment process for imparting roughness.

[0022] In addition, in the process of using laser to treat the surface of the implant, after the surface morphology of the grid pattern is formed for the first and second times, the surface treatment is further performed by acid etching. As a result, the entire surface morphology can be made regular and the surface area can be greatly increased. Therefore, after the implant is implanted, stable bone integration performance without deviation in different parts can be exerted, which brings the effect of shortening the healing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 As one method of implant surface treatment in the related art, a diagram briefly shows a surface treatment process based on sandblasting and a surface of an implant treated by sandblasting.

[0024] Figure 2 A diagram for explaining problems of conventional sandblasting surface treatment.

[0025] Figure 3 FIG. 1 is a schematic diagram of the process of a dental implant surface treatment method according to an embodiment of the present invention.

[0026] Figure 4 Schematic diagram of laser surface treatment performed in the first surface treatment step.

[0027] Figure 5 The SEM image and cross-sectional schematic diagram show the surface state of the implant after the first surface treatment step.

[0028] Figure 6 The present invention presents test data on the rate of increase in implant surface area when laser is used for implant surface treatment, compared with the conventional implant surface treatment method (SA, Sandblasted with alumina and acid etched).

[0029] Figure 7 This graph compares the surface roughness of implants treated by sandblasting (conventional implant surface treatment method), laser, and laser + acid etching (the present invention).

[0030] Figure 8 The figure shows SEM images of an implant surface treated by sandblasting and an implant surface treated by a surface treatment method (laser + acid etching) according to an embodiment of the present invention for comparison.

[0031] Figure 9 This is a front view of an implant that has been surface treated using a surface treatment method according to an embodiment of the present invention.

[0032] Figure 10 for Figure 9 A cutaway perspective view of an implant according to another embodiment of the present invention is shown.

[0033] Description of Reference Signs

[0034] 100: Implants

[0035] 101: External surface

[0036] 103: External thread

[0037] 104: External lower end thread section

[0038] 106: External upper thread section

[0039] 110: Internal slot

[0040] g1: first slot

[0041] g2: Second slot

[0042] c: Crater DETAILED DESCRIPTION

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0044] The terms used in the specification are used only to describe specific embodiments and are not intended to limit the present invention. As long as there is no clear different meaning in the context, a singular expression includes a plural expression.

[0045] It should be understood that, in this specification, terms such as "including" or "having" are intended to specify the features, numbers, steps, actions, structural elements, parts or their combinations recorded in the specification, rather than excluding in advance the existence or additional possibility of one or more other features or numbers, steps, actions, structural elements, parts or their combinations.

[0046] Furthermore, terms such as first and second may be used to describe various structural elements, but the structural elements should not be limited by the terms. The terms are only used to distinguish one structural element from other structural elements.

[0047] In the process of describing with reference to the accompanying drawings, the same structural elements are given the same reference numerals and repeated descriptions thereof are omitted. In addition, in the process of describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the main points of the present invention, the detailed description thereof will be omitted.

[0048] Figure 3 FIG. 1 is a schematic diagram illustrating the process of a dental implant surface treatment method according to an embodiment of the present invention.

[0049] Reference Figure 3 The surface treatment method of one embodiment of the present invention is a method for imparting roughness to the surface of an implant in a regular pattern to increase the surface area so that it can be implanted in the alveolar bone to prevent affecting the design of the implant forming the artificial tooth root and to achieve further improved bone integration performance. The method may include a first surface treatment step S100 using a laser and a second surface treatment step S200 using acid etching.

[0050] In the first surface treatment step S100, a laser may be used to form grooves in a regular pattern on all or part of the implant surface. Preferably, the regular pattern may be a grid pattern, wherein the grid pattern may include any pattern in which two groups of grooves arranged in other directions intersect each other at various angles, including right angles.

[0051] Specifically, the first surface treatment step S100 may include: a first laser processing process S102, processing a plurality of first grooves (hereinafter referred to as "first groove group G1") that are continuous in the first direction and separated in the second direction; and a second laser processing process S104, processing a plurality of second grooves (hereinafter referred to as "second groove group G2") that are continuous in the second direction and separated in the first direction, so as to form a crater c at each intersection of the first groove g1 and the second groove g2.

[0052] In an embodiment of the present invention, the first direction may be the circumferential direction of the implant, and the second direction may be the height direction of the implant intersecting the first direction, but is not limited thereto. For example, the first direction may be the same as or opposite to the direction formed by the threads formed on the surface of the implant, and the second direction may be a direction obliquely inclined relative to the height direction of the implant.

[0053] In the process of performing the first surface treatment using laser, the implant 100 as the surface treatment target may be clamped in a rotating device (not shown), such as Figure 4 The surface treatment schematic diagram shown in part (a) is that the rotating device is rotated or moved in a second direction relative to the laser generator 200 (equipment for irradiating the implant with laser light at a set intensity) which serves as a relatively fixed body, thereby forming a grid pattern of grooves.

[0054] In contrast, Figure 4 In the surface treatment schematic diagram shown in part (b), when the implant 100 as the surface treatment object is fixed to a fixing device (not shown), the laser generator 200 (equipment for irradiating the implant with laser light at a set intensity) as a relatively movable body is rotated or moved in a second direction relative to the implant 100 fixed to the fixing device, thereby forming the groove into a grid pattern.

[0055] Figure 5The SEM image and cross-sectional view illustrating the surface state of the implant after the first surface treatment step show that the first grooves g1 and the second grooves g2 are preferably formed in a grid pattern that intersect each other at right angles. In this case, the width w1 of the first groove g1 and the width w2 of the second groove g2 can be the same (w1=w2), and the depth d1 of the first groove g1 and the depth d2 of the second groove g2 can also be the same (d1=d2).

[0056] In which, preferably, the width w1 of the first groove g1 and the width w2 of the second groove g2 should be understood as the average width of the grooves g1 of the first groove group G1 and the groove g2 of the second groove group G2 formed in plurality, and preferably, the depth d1 of the first groove g1 and the depth d2 of the second groove g2 should also be understood as meaning the average depth of the grooves g1 and g2 included in the corresponding groups.

[0057] Preferably, the widths w1 and w2 of the first and second grooves g1 and g2 can be 5 μm to 30 μm. This is because if the widths w1 and w2 of the first and second grooves g1 and g2, which are formed in mutually intersecting directions, are less than 5 μm, the surface area increase effect is minimal, which may reduce bone integration properties. If the widths of the first and second grooves g1 and g2 are greater than 30 μm, there is a concern that the durability of the implant itself may be reduced.

[0058] Furthermore, preferably, the depths d1 and d2 of the first and second grooves g1 and g2 can be 5 μm to 10 μm. If the depths d1 and d2 of the first and second grooves g1 and g2 are less than 5 μm, the surface area increase effect is minimal. If the depths of the first and second grooves g1 and g2 are greater than 10 μm, the cracking of the micro-grooves g3 formed on the surfaces of the first and second grooves g1 and g2 can be reduced during the subsequent second surface treatment step.

[0059] In one embodiment of the present invention, when taking into account the density of the recess c per unit area and the bone integration characteristics based thereon, preferably, the second direction separation distance D1 between a first groove g1 and another adjacent first groove g1 is 5 μm to 20 μm, and, preferably, the first direction separation distance D2 between a second groove g2 formed in a direction intersecting with the first groove g1 and another adjacent second groove g2 is also 5 μm to 20 μm.

[0060] Figure 6This paper presents test data showing the rate of increase in implant surface area when laser-treated implants are compared to a conventional implant surface treatment method (SA, sandblasted with alumina and acid etched). The SA method, cited as a conventional implant surface treatment method, involves sandblasting the implant surface with fine aluminum oxide powder, followed by etching with sulfuric or hydrochloric acid to impart a roughened surface.

[0061] Reference Figure 6 It can be seen that when a laser is used to form a specific pattern of grooves (grid pattern grooves) on the surface of the implant, the surface area increases by at least 1.16 times and at most 1.3 times compared to the existing SA (Sandblasted with alumina and Acidetched) method, taking the same area as the surface area.

[0062] In particular, compared to the operating conditions of setting the laser processing speed to 450 mm / s and forming a groove depth of 5 μm, it can be seen that the surface area is further increased when the laser processing speed is maintained at 300 mm / s and a groove depth of 7 μm is formed. Based on this test data, the most optimal operating conditions in the first surface treatment step are a laser processing speed of 300 mm / s and a groove depth of 7 μm.

[0063] Alternatively, in the second surface treatment step S200, a grid-patterned groove pattern may be formed on the surface by laser processing, and the implant, which has been subjected to the initial surface roughness, may be exposed in acid to further impart a finer surface roughness. In the second surface treatment step S200, an etching solution such as sulfuric acid or hydrochloric acid may be used for further etching to impart a finer surface roughness.

[0064] As such, if the surface of the implant obtained by the first laser processing is further processed by exposing the implant in an etching solution such as sulfuric acid or hydrochloric acid for etching (second surface processing step S200), then Figure 3 As shown in the schematic diagram, the surface of the grooves g1 and g2 and their surroundings can be further roughened by means of micro grooves g3, thereby further improving the bonding force with the grooves (bone integration properties).

[0065] In the second surface treatment step S200 , hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, hydrogen peroxide, or a mixture of two or more thereof may be used as an etching solution for acid etching, but the invention is not limited thereto.

[0066] Preferably, in the second surface treatment step S200 of one embodiment of the present invention, the implant 100 is subjected to acid etching for approximately 5 to 10 minutes. If the etching time is less than 5 minutes, the chemical reaction time of the acid on the implant surface is too short to fully form micro grooves on the implant surface. If the etching time is greater than 10 minutes, although micro grooves can be fully formed, the strength of the implant may be significantly reduced.

[0067] Of course, it should be noted that the acid etching time may vary depending on the type of etching solution and is therefore not limited to the time mentioned above (5 minutes to 10 minutes).

[0068] Figure 7 This graph compares the surface roughness of implants treated by sandblasting (conventional implant surface treatment method), laser, and laser + acid etching (the present invention).

[0069] like Figure 7 As shown, it can be seen that compared with the surface treatment using sandblasting, the overall surface roughness is increased when the surface of the implant is treated by laser or laser + acid etching. In particular, it can be seen that compared with only using laser to treat the surface, the surface treatment method using the laser + acid etching method of the present invention has a significant effect in increasing the surface roughness.

[0070] Figure 8 The figure shows the SEM images for comparison of the implant surface after sandblasting and the implant surface treated by the surface treatment method (laser + acid etching) of one embodiment of the present invention. It can be confirmed that compared with the surface morphology of the implant after sandblasting, the surface morphology of the implant treated by the surface treatment method of the present invention has regular and more fine grooves.

[0071] According to the dental implant surface treatment method according to one embodiment of the present invention described above, roughness is imparted to the implant surface by utilizing laser precision processing. This can prevent the design of the implant surface threads or cutting edges from being accidentally damaged or altered during the surface treatment process for imparting roughness.

[0072] In addition, in the process of using laser to treat the surface of the implant, after the surface morphology of the grid pattern is formed for the first and second times, the surface treatment is further performed by acid etching. As a result, the entire surface morphology can be made regular and the surface area can be greatly increased. Therefore, after the implant is implanted, stable bone integration performance without deviation in different parts can be exerted, which brings the effect of shortening the healing time.

[0073] Next, as another embodiment of the present invention, a structure of a dental implant surface-treated by the surface treatment method according to one embodiment of the present invention will be briefly observed.

[0074] Figure 9 This is a front view of an implant having a surface treated by a surface treatment method according to an embodiment of the present invention. Figure 10 for Figure 9 A cutaway perspective view of an implant according to another embodiment of the present invention is shown.

[0075] Reference Figure 9 and Figure 10 A dental implant 100 according to another embodiment of the present invention, which is a structure implanted in alveolar bone to form an artificial tooth root, may include an outer surface 101 having an external thread 103 formed thereon for implantation in the alveolar bone. The external thread 103 formed on the outer surface 101 may be divided into two thread sections having the same pitch P and different groove depths relative to the height direction in the drawings.

[0076] Preferably, the two thread intervals constituting the external thread 103 can be divided into: an external lower end thread interval 104, formed at a first depth d3 at a specified height from the lower end of the outer peripheral surface of the implant 100 toward the upper side; and an external upper end thread interval 106, formed at a second depth d4 lower than the first depth d3 toward the top of the external lower end thread interval 104.

[0077] The two thread sections 104 and 106 with the same pitch P and different groove depths can be formed by successively pushing two cutting cutters (bites) with different processing surface shapes into the processing target surface of the implant 100 base material in the state before processing the thread, and then rotating the implant 100 body while moving the cutting cutters from the lower end to the upper end.

[0078] Like this, if the groove depth d4 of the thread of the external upper end thread section 106 of the implant 100 is formed in a manner that is lower than the groove depth d3 formed in the external lower end thread section 104, the implant 100 body can be more firmly fixed to the dense bone area of the alveolar bone surface, and the rigidity of the corresponding area can be increased by increasing the wall thickness of the upper area of the implant 100, thereby preventing longitudinal fracture from occurring in the upper end part of the implant 100.

[0079] Preferably, the outer upper end thread section 106, in which the groove depth of the thread is formed in a relatively low manner, can be formed to descend 2 to 5 threads from the edge of the upper surface of the implant 100 to the lower area. In this case, when performing a punching process to form a polygonal or star-shaped (Torx) bundle portion in the internal groove 110 formed on the inner side of the implant 100, the corners of the bundle portion can be indirectly strengthened to become the starting point of fatigue failure.

[0080] The external thread may include a non-threaded section H in the upper thread section 106. The non-threaded section H extends downward from the uppermost end of the implant 100 and is unthreaded for a predetermined period. This non-threaded section H may be provided to ensure robustness against longitudinal fractures at the upper end of the implant 100.

[0081] Since no threads are formed in the thread-free section H, when the implant 100 is implanted in the alveolar bone, the thread-free section H can be partially exposed to the upper surface of the alveolar bone, rather than being inserted into the inner side of the alveolar bone. However, since the thread-free section H is a very small section (0.2mm to 0.3mm) relative to the total length of the implant 100 body, when the thread-free section H is not implanted into the alveolar bone, the impact on the supporting rigidity of the implant 100 body within the alveolar bone is minimal.

[0082] Like this, if a threaded non-processed section H without threaded parts is formed at the upper end of the implant 100, then when the implant 100 is implanted in the alveolar bone, not only will the supporting force of the implant 100 body not be greatly reduced in the alveolar bone, but a constant level of wall thickness can be ensured for the upper end of the implant 100 body, thereby increasing the structural rigidity of the upper end of the implant 100.

[0083] The outer surface 101 of an implant 100 according to another embodiment of the present invention can be surface-treated using the aforementioned surface treatment method. This not only provides a regular surface morphology, but also significantly increases the surface area compared to conventional implants surface-treated by sandblasting, taking the same surface area as the implant. In this case, the outer upper threaded section 106 can form a crater c with a lower density than the outer lower threaded section 104.

[0084] For reference, a crater refers to a groove formed at the intersection of a first groove and a second groove.

[0085] Like this, if the outer lower end thread section is configured to have a higher density depression than the outer upper end thread section, that is, if the outer lower end thread section is configured to have a rougher surface than the outer upper end thread section, the effect of inhibiting bacterial proliferation and bone integration properties can be improved more balanced.

[0086] The implant 100 according to another embodiment of the present invention may further include an internal groove 110 formed at a predetermined depth from the upper surface to accommodate an abutment for supporting a restoration. The internal groove 110 may include an upper inclined portion 115, a polygonal portion 120, a bore section 130, and an internal screw section 160. The upper inclined portion 115, polygonal portion 120, bore section 130, and internal screw section 160 may be formed sequentially from the upper end of the implant.

[0087] The upper inclined portion 115 can be formed at a specified height from the upper end surface entrance of the implant 100, with a circular cross-sectional shape, and the inner diameter becomes narrower as it goes downward. The polygonal portion 120 can be formed at a specified height below the upper inclined portion 115, and the cross-sectional shape can be a polygon (for example, four-sided, six-sided, eight-sided) or a star (Torx) shape.

[0088] The internal screw portion 160 may be formed to a predetermined depth below the polygonal portion 120. A thread for engaging an abutment having a diameter smaller than a circle inscribed in the polygonal shape of the polygonal portion 120 may be formed in the internal screw portion 160, and a circular cross-sectional boring section 130 having a diameter larger than a diameter of a circle circumscribed in the polygonal shape of the polygonal portion 120 may be formed between the polygonal portion 120 and the internal screw portion 160.

[0089] The polygonal portion 120 can prevent the abutment (not shown) inserted into the internal groove 110 from rotating, and a screw (not shown) for securing the abutment to the implant 100 can be threadedly engaged with the internal screw portion 160. Furthermore, when the polygonal portion 120 is machined using the boring section 130, the base material of the upper inclined portion 115, which has been plastically deformed by the impact of the punching tool, is pushed downwardly from the polygonal portion 120, thereby preventing the accumulation of compressive residual stress and crack nucleation.

[0090] While the above detailed description of the present invention describes only specific embodiments thereof, the present invention should be understood not to be limited to the specific embodiments described in the detailed description but to encompass all variations, equivalents, and alternatives within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method for treating a surface of a dental implant, wherein the surface of the dental implant is treated to impart roughness to the surface, wherein: include: A first surface treatment step is to form a regular pattern of grooves on the entire or a portion of the implant surface using a laser; as well as The second surface treatment step is to impart roughness to the groove and the periphery of the groove by acid etching, The first surface treatment step comprises: A first laser processing step is performed to process a plurality of first grooves that are continuous in the first direction and spaced apart in the second direction; as well as The second laser processing step processes a plurality of second grooves that are continuous in the second direction and spaced apart in the first direction, so as to form a crater at each intersection of the first groove and the second groove.

2. The dental implant surface treatment method according to claim 1, characterized in that: The first direction is the circumferential direction of the implant, The second direction is a height direction of the implant intersecting with the first direction.

3. A method for treating the surface of a dental implant, characterized in that: The width ( w1 ) and depth ( d1 ) of the first groove are the same as the width ( w2 ) and depth ( d2 ) of the second groove.

4. The dental implant surface treatment method according to claim 3, characterized in that: The width (w1, w2) of the first groove and the second groove is 5 μm to 30 μm, and the depth (d1, d2) is 5 μm to 10 μm.

5. The dental implant surface treatment method according to claim 3, characterized in that: The second direction spacing distance (D1) between one first groove and another adjacent first groove is 5 μm to 20 μm, A first-direction spacing distance (D2) between one second groove and another adjacent second groove is 5 μm to 20 μm.

6. The dental implant surface treatment method according to claim 1, wherein: In the second surface treatment step, acid etching is performed on the implant for 5 to 10 minutes.

7. A dental implant implanted in alveolar bone to form an artificial tooth root, characterized in that: include: An internal groove, formed at a specific depth from the upper end surface and incorporating an abutment to support the restoration; The outer surface is formed with an external thread for implantation into the alveolar bone. The entire or a portion of the external surface is surface-treated by the surface treatment method according to any one of claims 1 to 6.

8. The dental implant according to claim 7, characterized in that The external thread comprises: an outer lower threaded section formed at a first depth at a first height from a lower end of the implant upward; and The outer upper thread section is formed at a second height above the outer lower thread section at a second depth lower than the first depth.

9. The dental implant according to claim 8, characterized in that The density of the craters formed by surface treatment in the outer upper thread section is lower than that in the outer lower thread section.

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