Dental implant fixtures and dental implants

Abstract

To provide a fixture for dental implants that can maintain apatite alignment in regenerated cortical bone.SOLUTION: A fixture for dental implants according to an embodiment of the present invention is provided with a small groove 4. The small groove comprises a first side wall positioned on a leading end 21 side and a second side wall positioned on a trailing end 22 side. The first side wall extends away from a first reference plane with increasing distance from a first bottom part, and the second side wall extends parallel to the first reference plane or extends away from the first reference plane with increasing distance from the first bottom part. The angle formed between the first side wall and the first reference plane is larger than the angle formed between the second side wall and the first reference plane. A dental implant provided with this fixture for dental implants is also provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a dental implant fixture and a dental implant including the same. [Background technology]

[0002] Dental implant surgery has traditionally been performed to restore occlusal function, speech function, aesthetics, etc. by implanting dental implant fixtures (hereinafter sometimes referred to as "fixtures") into the alveolar bone of the upper and lower jaws (see, for example, Patent Document 1).

[0003] Patent Document 2 proposes a fixture having a screw thread on its outer periphery and a groove extending along the screw thread. This fixture is configured so that bone tissue can grow inside the groove extending along the screw thread.

[0004] On the other hand, apatite, the main component of bone, is known to have crystallographic anisotropy (see, for example, Patent Document 3 and Non-Patent Documents 1 and 2). For example, the orientation of apatite in the mandible changes depending on the part of the mandible (see, for example, Non-Patent Document 2). Specifically, the orientation in the direction of masticatory load is dominant at the margins close to the teeth, while the orientation in the mesio-distal direction is dominant in the bone body.

[0005] Since such apatite orientation maintains the inherent mechanical function of bone, it is believed that if apatite orientation is maintained during bone regeneration, new bone will be generated faster and bone quality will be maintained for a long period of time. In particular, it is desirable to maintain apatite orientation in the regenerating cortical bone at the posterior part of the implant, which is susceptible to load due to the attachment of structural components.

[0006] However, in conventional fixtures such as those described in Patent Document 2, the above-mentioned apatite orientation is not taken into consideration. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 4740139 [Patent Document 2] Patent No. 4603893 [Patent Document 3] Patent No. 5153626 [Non-patent literature]

[0008] [Non-Patent Document 1] Yoshihiro Noyama, Takayoshi Nakano, Takuya Ishimoto, Takashi Sakai, Hideki Yoshikawa, “Design and optimization of the oriented groove on the hip implant surface to promote bone microstructure integrity”, Bone, 2013, 52, p. 659-667 [Non-Patent Document 2] Hideki Yoshikawa, Takayuki Nakano, Atsuko Matsuoka, Yoshio Nakajima, "Towards the Future of Artificial Joints - From History to Future Prospects", 1st edition, Japan Medical Library Co., Ltd., July 1, 2013, pp. 349-351 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a dental implant fixture and a dental implant that can maintain apatite orientation in regenerating cortical bone. [Means for solving the problem]

[0010] A dental implant fixture according to an embodiment of the present invention comprises a cylindrical main body portion, a large groove portion located on the tip side of the main body portion on the outer periphery of the main body portion, and at least one small groove portion located on the rear end side of the main body portion on the outer periphery, the at least one small groove portion having a first bottom portion, a first side wall portion connected to one end of the first bottom portion and located on the tip side, and a second side wall portion connected to the other end of the first bottom portion and located on the rear end side, the first side wall portion extends so as to move away from a first reference plane passing through the first bottom portion and perpendicular to a central axis of the main body portion as it moves away from the first bottom portion, the second side wall portion extends parallel to the first reference plane or moves away from the first reference plane as it moves away from the first bottom portion, and in a cross-sectional view parallel to the central axis, an angle α between the first side wall portion and the first reference plane is greater than an angle β between the second side wall portion and the first reference plane.

[0011] A dental implant according to an embodiment of the present invention comprises a dental implant fixture according to the above-described embodiment and a structural component attached to the rear end of the body portion of the dental implant fixture. Effect of the Invention

[0012] The dental implant fixture according to the embodiment of the present invention has an effect of maintaining apatite orientation in regenerated cortical bone. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a side view showing a dental implant fixture according to a first embodiment of the present invention. [Diagram 2] 2 is a partially enlarged cross-sectional view showing a small groove portion of the dental implant fixture shown in FIG. 1. [Diagram 3] 2 is a partially enlarged cross-sectional view showing a large groove portion of the dental implant fixture shown in FIG. 1. [Figure 4]FIG. 5 is a partially enlarged cross-sectional view showing a small groove portion of a dental implant fixture according to a second embodiment of the present invention. [Diagram 5] 5 is a partially enlarged cross-sectional view showing a large groove portion of the dental implant fixture shown in FIG. 4. [Figure 6] 1 is a diagram showing a dental implant fixture according to a third embodiment of the present invention, in which (a) is a side view and (b) is a schematic explanatory view showing a large groove portion and a small groove portion, where (a) corresponds to a side view seen from an angle different from that of FIG. [Figure 7] 7 is a partially enlarged side view showing the rear end side of the main body of the dental implant fixture shown in FIG. 6. [Figure 8] 7 is a partially enlarged cross-sectional view showing the boundary between the large groove portion and the small groove portion in the dental implant fixture shown in FIG. 6. [Figure 9] FIG. 1 is a side view of a dental implant according to an embodiment of the present invention. [Figure 10] FIG. 1(a) to (c) are schematic explanatory views showing a dental implant embedding operation according to a first embodiment of the present invention. [Figure 11] 1(a) to 1(c) are schematic explanatory views showing a dental implant embedding operation according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Dental implant fixture> (First embodiment) Hereinafter, a dental implant fixture according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. FIG.

[0015] As shown in Fig. 1, the fixture 1A of this embodiment includes a substantially cylindrical main body 2. The main body 2 has a tip end 21 and a rear end 22. As shown in Figs. 10(b) and (c) described later, the tip end 21 is a portion located on the cancellous bone 113 side of the alveolar bone 111 when the fixture 1A is embedded in the jawbone 110. The rear end 22 is a portion located on the cortical bone 112 side of the alveolar bone 111 when the fixture 1A is embedded in the jawbone 110.

[0016] As shown in FIG. 1, the main body 2 further has an outer peripheral portion 23. The outer peripheral portion 23 has a front portion 231 located on the tip portion 21 side and a rear portion 232 located on the rear end portion 22 side. The front portion 231 is a portion located in the cancellous bone 113 when the fixture 1A is embedded in the jawbone 110. The rear portion 232 is a portion located in the cortical bone 112 when the fixture 1A is embedded in the jawbone 110. In this embodiment, the area of ​​the front portion 231 is larger than the area of ​​the rear portion 232. The front portion 231 is configured in a tapered shape that becomes smaller in diameter from the vicinity of its center toward the front portion 21.

[0017] The fixture 1A of this embodiment further includes a large groove portion 3 located in the front portion 231 of the outer periphery 23, and at least one small groove portion 4 located in the rear portion 232. In other words, the fixture 1A of this embodiment further includes a large groove portion 3 located in the outer periphery 23 on the tip portion 21 side of the main body portion 2, and at least one small groove portion 4 located in the outer periphery 23 on the rear end portion 22 side of the main body portion 2.

[0018] The large groove portion 3 is a so-called body thread. The large groove portion 3 in this embodiment is located in a spiral shape at the tip portion 231. In other words, the large groove portion 3 in this embodiment extends in a spiral shape at the tip portion 21 side. With this configuration, the fixture 1A can be embedded in the alveolar bone 111 while being screwed in by self-tapping. The large groove portion 3 in this embodiment is located over the entire circumference of the tip portion 231. Therefore, when the fixture 1A is embedded in the alveolar bone 111, the large groove portion 3 is located in the cancellous bone 113.

[0019] On the other hand, the small groove portion 4 is a so-called microthread that functions as a portion for regenerating the cortical bone 112 therein, as shown in Figs. 10(b) and (c). The small groove portion 4 is a portion having a groove width and groove depth that are substantially smaller than those of the large groove portion 3 described above. The groove width refers to the dimension of a straight line connecting the opposing edges at the opening of the groove portion (large groove portion 3 or small groove portion 4). The groove depth refers to the dimension of the groove portion in a direction perpendicular to the central axis S1 of the main body portion 2. The central axis S1 of the main body portion 2 refers to an axis that passes through the front end portion 21 and the rear end portion 22 of the main body portion 2 as shown in Fig. 1, and refers to an axis that becomes the rotation axis when the fixture 1A is rotated.

[0020] The small groove portion 4 of this embodiment is located in a spiral shape in the rear portion 232. In other words, the small groove portion 4 of this embodiment extends in a spiral shape on the rear end portion 22 side. The small groove portion 4 of this embodiment is located around the entire circumference of the rear portion 232. As shown in FIG. 2, the small groove portion 4 of this embodiment is a so-called double thread of a first small groove portion 4A and a second small groove portion 4B located apart from each other. The number of small groove portions 4 is preferably 1 to 4. When the number of small groove portions 4 is more than one, the configurations of the multiple small groove portions 4 may be the same or different from each other. In this embodiment, since the first small groove portion 4A and the second small groove portion 4B have substantially the same configuration, the following description of the first small groove portion 4A will replace the description of the second small groove portion 4B. In addition, the first small groove portion 4A may be described by assigning a reference number to the second small groove portion 4B.

[0021] The first small groove portion 4A of this embodiment has a first bottom portion 41, a first side wall portion 42 connected to one end 41a of the first bottom portion 41, and a second side wall portion 43 connected to the other end 41b of the first bottom portion 41. The first bottom portion 41 is a portion including an area of ​​the first small groove portion 4A where the groove depth is greatest. The first side wall portion 42 is located on the tip end portion 21 side of the main body portion 2, and the second side wall portion 43 is located on the rear end portion 22 side of the main body portion 2. In this embodiment, both the first side wall portion 42 and the second side wall portion 43 are planar.

[0022] In this embodiment, the first side wall 42 extends away from the first reference plane S2 as it moves away from the first bottom 41, in other words, as it moves outward from the first bottom 41 as indicated by the arrow A. The second side wall 43 extends away from the first reference plane S2 as it moves away from the first bottom 41. In addition, in a cross-sectional view parallel to the central axis S1 shown in FIG. 2, the angle α between the first side wall 42 and the first reference plane S2 is larger than the angle β between the second side wall 43 and the first reference plane S2. In other words, the angle α and the angle β have a relationship of α>β. With this configuration, the cortical bone 112 can be guided into the first small groove portion 4A and regenerated while maintaining the apatite orientation, which is expected to accelerate bone regeneration and maintain bone quality for a long period of time.

[0023] Here, the following experiment was carried out to examine the relationship between the size of the angles α and β. In other words, an in vivo experiment was carried out in which a fixture was embedded in the tibia of a rabbit and repeated loads were applied. Then, histomorphological analysis was carried out based on the bone area ratio and bone contact ratio, and three-dimensional structural analysis was carried out using indices such as BVF, Tb.N, Tb.Th, Tv.Sp, and BMD. Furthermore, the number of osteocytes generated in the groove and the apatite orientation were investigated. As a result, the groove with α>β had a larger amount of newly formed bone and a larger number of osteocytes than the groove with α<β. Apatite orientation was observed along the sidewall of the groove with both relationships, but it was found that in terms of bone volume and bone quality, α>β was superior to α<β.

[0024] The above-mentioned "outside" refers to the outside of the fixture 1A with respect to the first bottom portion 41, and the direction opposite to the inside on the central axis S1 side. The above-mentioned first reference plane S2 refers to a plane that passes through the first bottom portion 41 and is perpendicular to the central axis S1 of the main body portion 2.

[0025] The above-mentioned angles α and β are both acute angles. The angle α is preferably 40 to 65°, and more preferably 45 to 60°. The angle β is preferably 1 to 15°, and more preferably 5 to 10°.

[0026] In the present embodiment, in the above-mentioned cross-sectional view, of the edges 46a, 46b facing each other at the opening 46 of the first small groove portion 4A, the edge 46a located on the second side wall portion 43 side has an outwardly convex curved shape. With this configuration, it is possible to suppress bone resorption.

[0027] In this embodiment, the following configuration is provided from the viewpoint of guiding the cortical bone 112 into the first small groove portion 4A and regenerating it while maintaining the apatite orientation. That is, in the above-mentioned cross-sectional view, the first connection portion 44 of the first bottom portion 41 and the first side wall portion 42 is located closer to the central axis S1 than the second connection portion 45 of the first bottom portion 41 and the second side wall portion 43. In addition, in the above-mentioned cross-sectional view, the length L42 of the first side wall portion 42 is greater than the length L43 of the second side wall portion 43. In this embodiment, as described above, the edge portion 46a of the first small groove portion 4A is curved and convex outward. In this embodiment, the length L43 of the second side wall portion 43 is determined based on the end portion 46a1 of the edge portion 46a located closer to the first bottom portion 41.

[0028] In this embodiment, in the cross-sectional view described above, the first bottom 41 is curved and convex inward. With this configuration, the surface area and volume of the first small groove 4A can be increased while maintaining the strength of the first small groove 4A, so that a large amount of cortical bone 112 can be guided into the first small groove 4A and regenerated while maintaining the apatite orientation. In addition, when the first small groove 4A is cleaned with a cleaning means such as a titanium brush, the tip of the brush can easily move along the shape of the first small groove 4A, so that excellent cleaning properties can be exhibited. Note that the above-mentioned inward side means the inside of the fixture 1A with respect to the first side wall 42 and the second side wall 43, and the side of the central axis S1.

[0029] As described above, the first bottom 41 of this embodiment has an inwardly convex curved shape in the above-mentioned cross-sectional view, and examples of the curved shape include a parabolic shape, an elliptical arc shape, and an arc shape. The first bottom 41 of this embodiment has an inwardly convex arc shape in the above-mentioned cross-sectional view. More specifically, the first bottom 41 of this embodiment has an inwardly convex arc shape whose center O has the following specific positional relationship.

[0030] That is, in the above-mentioned cross-sectional view, the first straight line L1 and the second straight line L2 are set as follows. First straight line L1: A straight line connecting the opposing edges 46a, 46b of the opening 46 of the first small groove 4A. In this embodiment, as described above, the edge 46a of the first small groove 4A has an outwardly convex curved shape. In this embodiment, the first straight line L1 is determined based on the end 46a2 of the edge 46a located on the side farther from the first bottom 41. Second straight line L2: A straight line that passes through the midpoint M of the first straight line L1 and is perpendicular to the central axis S1.

[0031] The center O of the first bottom portion 41 has the following positional relationships (i) and (ii) with respect to the above-mentioned first straight line L1 and second straight line L2. (i) The center O of the first bottom portion 41 is located closer to the central axis S1 than the first straight line L1. (ii) The center O of the first bottom portion 41 is located closer to the rear end portion 22 of the main body portion 2 than the second straight line L2.

[0032] According to the above-mentioned configuration, among the above-mentioned effects due to the first bottom 41 being curved inwardly convex, the effect of increasing the surface area and volume of the first small groove 4A while maintaining the strength of the first small groove 4A can be improved. Also, capillaries of several hundred μm can penetrate to the first bottom 41. Therefore, the amount of newly formed bone is increased, and an improvement in the contact rate between the bone and the fixture 1A can be expected.

[0033] In the above-mentioned cross-sectional view, the first small groove portion 4A of this embodiment has a groove width W at the opening 46 that is larger than the groove depth D. With this configuration, it is easier to guide the cortical bone 112 into the inside of the first small groove portion 4A while maintaining the apatite orientation. In this embodiment, as described above, the edge portion 46a of the first small groove portion 4A has an outwardly convex curved shape. In this embodiment, the groove width W is determined based on the end portion 46a1 of the edge portion 46a located closer to the first bottom portion 41.

[0034] On the other hand, in this embodiment, the large groove portion 3 has substantially the same configuration as the small groove portion 4. That is, as shown in FIG. 3, the large groove portion 3 in this embodiment has a second bottom portion 31, a third side wall portion 32 connected to one end 31a of the second bottom portion 31 and located on the tip portion 21 side, and a fourth side wall portion 33 connected to the other end 31b of the second bottom portion 31 and located on the rear end portion 22 side. The third side wall portion 32 extends so as to move away from the second reference plane S3 that passes through the second bottom portion 31 and is perpendicular to the central axis S1 as it moves away from the second bottom portion 31, similar to the first side wall portion 42 of the small groove portion 4. Also, as described above, in this embodiment, the second side wall portion 43 of the small groove portion 4 extends so as to move away from the first reference plane S2 as it moves away from the first bottom portion 41, so that the fourth side wall portion 33 of the large groove portion 3 also extends so as to move away from the second reference plane S3 as it moves away from the second bottom portion 31. In the cross-sectional view parallel to the central axis S1 shown in FIG. 3, the angle γ between the third side wall portion 32 and the second reference plane S3 is larger than the angle δ between the fourth side wall portion 33 and the second reference plane S3. In other words, the angle γ and the angle δ have a relationship of γ>δ. According to such a configuration, the change in the configuration from the large groove portion 3 to the small groove portion 4 can be reduced, so that the embeddability when the fixture 1A is embedded in the alveolar bone 111 in the order of the large groove portion 3 and the small groove portion 4 can be improved. As a result, the occurrence of bone necrosis can be suppressed. In addition, it is possible to reduce the inhibitory factors when the cortical bone 112 is guided into the inside of the small groove portion 4 and regenerated while maintaining the apatite orientation. Furthermore, it is possible to promote the modification (remodeling) of the bone. Note that the configuration of the large groove portion 3 is not limited to a configuration substantially the same as that of the small groove portion 4 as long as it can perform its function.

[0035] In this embodiment, the angle α of the first side wall 42 in the small groove 4 is larger than the angle γ of the third side wall 32 in the large groove 3. The angle β of the second side wall 43 in the small groove 4 and the angle δ of the fourth side wall 33 in the large groove 3 are the same. That is, in this embodiment, the angles α and γ have a relationship of α>γ, and the angles β and δ have a relationship of β=δ. These configurations tend to improve the embeddability when the fixture 1A is embedded in the alveolar bone 111. In this embodiment, the angles α, β, γ are set to 50°, 10°, 45°, and δ are set to 10°, respectively, but are not limited to these. The angles β and δ being the same means that the angles are substantially the same. This also applies to the embodiments described later.

[0036] The fixture 1A of the present embodiment described above is preferably manufactured by an additive manufacturing method. This allows the fixture 1A to be obtained with excellent processing accuracy. The manufacturing method of the fixture 1A is not limited to the additive manufacturing method as long as the fixture 1A can be obtained. Other manufacturing methods of the fixture 1A include, for example, cutting processing.

[0037] Second embodiment Next, a fixture according to a second embodiment of the present invention will be described in detail with reference to Figures 4 and 5. In Figures 4 and 5, the same components as those in Figures 1 to 3 described above are denoted by the same reference numerals, and the description thereof may be omitted.

[0038] As shown in FIG. 4, in the fixture 1B of this embodiment, the second side wall 43 of the small groove 4 extends parallel to the first reference plane S2. In other words, in the fixture 1B of this embodiment, the angle β between the second side wall 43 and the first reference plane S2 is 0°. The angles α and β have a relationship of α>β. With this configuration, it is easy to guide the cortical bone 112 into the small groove 4 while maintaining the apatite orientation. Note that it is sufficient that the second side wall 43 extends substantially parallel to the first reference plane S2.

[0039] As shown in FIG. 5, in the fixture 1B of this embodiment, the large groove portion 3 has a configuration substantially the same as that of the small groove portion 4. That is, in this embodiment, as described above, since the second side wall portion 43 in the small groove portion 4 extends parallel to the first reference plane S2, the fourth side wall portion 33 in the large groove portion 3 also extends parallel to the second reference plane S3. In other words, the angle δ between the fourth side wall portion 33 and the second reference plane S3 is 0°. The angles γ and δ have a relationship of γ>δ. According to such a configuration, as in the first embodiment described above, the change in the configuration from the large groove portion 3 to the small groove portion 4 can be reduced, so that the embeddability when the fixture 1B is embedded in the alveolar bone 111 in the order of the large groove portion 3 and the small groove portion 4 can be improved. As a result, the occurrence of bone necrosis can be suppressed. In addition, it is possible to reduce the inhibitory factors when the cortical bone 112 is guided into the inside of the small groove portion 4 and regenerated while maintaining the apatite orientation. Furthermore, it is possible to promote bone remodeling. The fourth side wall portion 33 only needs to extend substantially parallel to the second reference plane S3.

[0040] In this embodiment, the angle α of the first side wall 42 in the small groove 4 is the same as the angle γ of the third side wall 32 in the large groove 3. That is, in this embodiment, the angles α and γ have a relationship of α=γ. This configuration tends to improve the embedding property when embedding the fixture 1B in the alveolar bone 111. In this embodiment, both the angles α and γ are set to 45°, but are not limited to this. The other configuration is similar to that of the fixture 1A according to the first embodiment described above, and therefore a description thereof will be omitted.

[0041] Third embodiment Next, a dental implant fixture according to a third embodiment of the present invention will be described in detail with reference to Figures 6 to 8. In Figures 6 to 8, the same components as those in Figures 1 to 5 described above are denoted by the same reference numerals, and the description thereof may be omitted.

[0042] As shown in Figure 6, the fixture 1C of this embodiment has a large groove portion 3 located on the tip end 21 side of the main body portion 2 of the outer periphery 23, and at least one small groove portion 4 located on the rear end 22 side of the main body portion 2 of the outer periphery 23.

[0043] In this embodiment, the portion of the outer periphery 23 where the large groove portion 3 is located is configured to have a tapered shape that becomes smaller in diameter from the vicinity of the center toward the tip portion 21. Moreover, the area of ​​the portion of the outer periphery 23 where the large groove portion 3 is located is larger than the area of ​​the portion where the small groove portion 4 is located.

[0044] The small grooves 4 in this embodiment are two in number, and are so-called double threads consisting of a first small groove 4A and a second small groove 4B that are spaced apart from each other. In this embodiment, the first small groove 4A and the second small groove 4B have substantially the same configuration.

[0045] In this embodiment, both the large groove portion 3 and the small groove portion 4 extend in a spiral shape. With this configuration, it is possible to reduce the embedding resistance when embedding the fixture 1C in the alveolar bone 111.

[0046] In this embodiment, at the boundary 5 between the large groove 3 and the small groove 4, the portion 31 located on the rear end 22 side of the large groove 3 and the portion 47 located on the tip end 21 side of the small groove 4 run parallel to each other. With this configuration, when the fixture 1C is embedded in the alveolar bone 111 in the order of the large groove 3 and the small groove 4, the configuration gradually switches from the large groove 3 to the small groove 4 at the boundary 5 between the large groove 3 and the small groove 4, so that it is possible to keep the embedding resistance constant when embedding the fixture 1C in the alveolar bone 111. Also, at the boundary 5 between the large groove 3 and the small groove 4, the area of ​​the portion of the outer periphery 23 of the main body 2 where the large groove 3 and the small groove 4 do not exist is reduced, so that it is possible to reduce the embedding resistance when embedding the fixture 1C in the alveolar bone 111. These effects, combined with the effect of the large groove portion 3 and the small groove portion 4 both extending in a spiral shape, provide the effect of making it easier to embed the fixture 1C in the alveolar bone 111. As a result, the occurrence of bone necrosis can be suppressed. In addition, it is possible to reduce inhibitors when guiding the cortical bone 112 into the inside of the small groove portion 4 and regenerating it while maintaining the apatite orientation. Furthermore, it is possible to promote bone remodeling.

[0047] The boundary 5 between the large groove portion 3 and the small groove portion 4 means a region including an end portion 48 located on the tip end portion 21 side of the small groove portion 4 and an end portion 32 located on the rear end portion 22 side of the large groove portion 3, as shown in FIG. 6(b). In addition, in FIG. 6(b), the line showing the large groove portion 3 represents the second bottom portion 31 of the large groove portion 3 (see FIGS. 3 and 5). This also applies to the small groove portion 4. That is, in FIG. 6(b), the line showing the small groove portion 4 represents the first bottom portion 41 of the small groove portion 4 (see FIGS. 2 and 4).

[0048] The part 31 of the large groove part 3 and the part 47 of the small groove part 4 running parallel to each other means that the parts 31 and 47 extend side by side. The parts 31 and 47 may run parallel to each other while being separated from each other, or may run parallel to each other while being partially joined. Partially joined means that a part of the part 31 and a part of the part 47 join each other to the extent that the parts 31 and 47 can perform their respective functions. In this embodiment, as shown in FIG. 7 and FIG. 8, the parts 31 and 47 run parallel to each other while being partially joined. With such a configuration, it is possible to smoothly switch the configuration from the large groove part 3 to the small groove part 4.

[0049] 6, in this embodiment, at the boundary 5 between the large groove portion 3 and the small groove portion 4, the portion 31 of the large groove portion 3 and the portion 47 of the small groove portion 4 run parallel to each other in the following state: That is, in this embodiment, the portion 47a of the portion 47 of the small groove portion 4, where the groove depth D4 is greatest, is located approximately in the center of the boundary 5 between the large groove portion 3 and the small groove portion 4, and the portions 31 and 47 run parallel to each other.

[0050] In this embodiment, the portions 31 and 47 run parallel to each other in such a state that the angle θ1 between the reference line S4 parallel to the central axis S1 and the portion 31 of the large groove portion 3 is larger than the angle θ2 between the reference line S4 and the portion 47 of the small groove portion 4. In other words, in this embodiment, the angle θ1 is larger than the angle θ2. That is, in this embodiment, the angles θ1 and θ2 have the relationship θ1>θ2.

[0051] Both angles θ1 and θ2 are preferably acute angles. With this configuration, at the boundary 5 between the large groove portion 3 and the small groove portion 4, the portion 31 of the large groove portion 3 gradually reaches the end portion 32 located on the rear end portion 22 side of the large groove portion 3, and the portion 47 of the small groove portion 4 gradually reaches the portion 47a where the groove depth D4 is the largest, so that it is possible to smoothly switch the configuration from the large groove portion 3 to the small groove portion 4. The angle θ1 is preferably 15 to 25°, and the angle θ2 is preferably 10 to 20°, but is not limited thereto.

[0052] In this embodiment, the groove depth D3 of the portion 31 of the large groove portion 3 decreases toward the rear end portion 22, and the groove depth D4 of the portion 47 of the small groove portion 4 increases toward the rear end portion 22. Even with this configuration, at the boundary portion 5 between the large groove portion 3 and the small groove portion 4, the portion 31 of the large groove portion 3 gradually reaches the end portion 32, and the portion 47 of the small groove portion 4 gradually reaches the portion 47a where the groove depth D4 is greatest, so that it is possible to smoothly switch the configuration from the large groove portion 3 to the small groove portion 4.

[0053] On the other hand, the main body 2 of this embodiment further has a bevel 6 located on the rear end 22 side. When the fixture 1C is viewed from a direction perpendicular to the central axis S1, the bevel 6 of this embodiment is substantially trapezoidal in shape with the long side 61 on the tip end 21 side. Furthermore, as shown in FIG. 11(c) described later, the bevel 6 is a portion that is exposed from the cortical bone 112 when the fixture 1C is embedded in the alveolar bone 111. The above-mentioned long side 61 of the bevel 6 is located at the boundary between the cortical bone 112 and the gums 101, and thus constitutes the bone margin line L.

[0054] Here, in this embodiment, as shown in FIG. 7, the end 49 located on the rear end 22 side of the small groove 4 is located closer to the tip 21 side than the bone margin line L located on the rear end 22 side of the outer circumferential portion 23. With this configuration, excellent sealing properties can be exhibited and the strength of the fixture 1C itself can be improved. Also, in this embodiment, the end 49 of the small groove 4 is located near the bone margin line L. With this configuration, a large area can be secured for the small groove 4. In the small groove 4 of this embodiment, as shown in FIG. 6(b), the groove depth D4 decreases toward the end 49 side. The other configurations are similar to those of the fixtures 1A and 1B according to the first and second embodiments described above, and therefore will not be described.

[0055] <Dental implants> Next, a dental implant according to an embodiment of the present invention will be described in detail with reference to FIG. 9, taking as an example a case in which the fixture 1A according to the first embodiment described above is used.

[0056] As shown in FIG. 9, the dental implant 10 of this embodiment includes the above-mentioned fixture 1A and an artificial tooth 11 as a structural component attached to the rear end portion 22 of the main body portion 2 of the fixture 1A.

[0057] The artificial tooth 11 is a so-called artificial tooth, and may be made of, for example, metal, ceramic, or hard resin. The artificial tooth 11 is usually made to order and attached to the rear end 22 of the fixture 1A via an abutment 12. The artificial tooth 11 may be a single type or a linked type (bridge). Note that, instead of the artificial tooth 11, other artificial teeth may be used as structural components. Examples of other artificial teeth include dentures. Examples of dentures include so-called dentures such as partial dentures or full dentures. The dentures are attached to the rear end 22 of the fixture 1A via an attachment in a removable state.

[0058] In this embodiment, the case where the fixture 1A is used has been described as an example, but a dental implant that provides similar effects can be obtained by using fixtures 1B and 1C instead of the fixture 1A.

[0059] <Dental implant surgery> (First embodiment) Next, a dental implant embedding operation according to the first embodiment of the present invention will be described in detail with reference to FIG. 10, taking as an example a case in which the fixture 1A according to the first embodiment described above is used.

[0060] 10(a), an embedding hole 100 is bored with a drill or the like in the gums 101 and the alveolar bone 111 of the jawbone 110. The embedding hole 100 of this embodiment has a shape that is slightly smaller than the fixture 1A.

[0061] Next, as shown in FIG. 10(b), the fixture 1A is embedded in the drilled embedding hole 100. After a load-relief period of several weeks to several months, cortical bone 112 is regenerated inside the small groove portion 4. In this embodiment, as described above, the angles α and β of the first side wall portion 42 and the second side wall portion 43 in the small groove portion 4 have a relationship of α>β, so that the cortical bone 112 is guided into the small groove portion 4 and regenerated while maintaining the apatite orientation. Therefore, according to this embodiment, it is expected that bone regeneration will be rapid and bone quality will be maintained for a long period of time.

[0062] During the unloading period, in order to protect the gums 101, it is preferable to attach a healing cap 13 to the rear end 22 as shown in Fig. 10(b). After the fixture 1A has been fixed to the jawbone 110, the healing cap 13 is removed from the rear end 22 as shown in Fig. 10(c), and structural components such as the artificial tooth 11 described above are attached to the rear end 22 to form a dental implant, completing the treatment.

[0063] Second embodiment Next, a dental implant embedding operation according to the second embodiment of the present invention will be described in detail with reference to Fig. 11, taking as an example a case where the fixture 1C according to the third embodiment described above is used. In Fig. 11, the same components as those in Fig. 10 described above are given the same reference numerals, and the description thereof may be omitted.

[0064] First, as shown in FIG. 11(a), an embedding hole 100 is drilled in the gums 101 and the alveolar bone 111 in the same manner as in the first embodiment described above.

[0065] Next, as shown in FIG. 11(b), the fixture 1C is embedded in the drilled embedding hole 100. In this embodiment, as described above, the large groove portion 3 and the small groove portion 4 both extend in a spiral shape, and at the boundary portion 5 between the large groove portion 3 and the small groove portion 4, the portion 31 located on the rear end portion 22 side of the large groove portion 3 and the portion 47 located on the tip end portion 21 side of the small groove portion 4 run parallel to each other, so that the fixture 1C can be smoothly embedded in the embedding hole 100 (alveolar bone 111). As a result, the occurrence of bone necrosis can be suppressed. In addition, it is possible to reduce the inhibitory factors when the cortical bone 112 is guided into the inside of the small groove portion 4 and regenerated while maintaining the apatite orientation. Furthermore, it is possible to promote bone remodeling.

[0066] After embedding the fixture 1C in the embedding hole 100, as shown in FIG. 11(c), the fixation of the fixture 1C to the jawbone 110 is completed in the same manner as in the first embodiment described above, and a structural component is attached to the rear end portion 22 to form a dental implant, thereby completing the treatment.

[0067] In the above-mentioned first and second embodiments, the cases where the fixtures 1A and 1C are used have been described as examples. However, the same effect can be obtained by using the fixture 1B instead of the fixtures 1A and 1C.

Claims

1. a body portion having a leading end and a trailing end; a large groove portion and a small groove portion that open to the outside of the main body portion and are located in this order from the front end portion to the rear end portion; a boundary portion where the large groove portion and the small groove portion run side by side while partially joining each other, A dental implant fixture, wherein, at the boundary portion, the large groove portion has a region where the groove depth decreases toward the rear end portion, and the small groove portion has a region where the groove depth increases toward the rear end portion.

2. The dental implant fixture of claim 1 , wherein the major groove and the minor groove extend in a spiral fashion.

3. The dental implant fixture according to claim 1 , wherein the boundary portion has an end portion on the tip end side of the smaller groove portion and an end portion on the rear end side of the larger groove portion.

4. The dental implant fixture according to claim 1 , wherein the larger groove portion and the smaller groove portion extend continuously at the boundary portion.

5. The dental implant fixture according to claim 1 , wherein at the boundary portion, the large groove portion and the small groove portion overlap on the inside of the main body portion relative to the outer periphery of the main body portion.

6. The dental implant fixture of claim 1 , further comprising a bevel located on the rear end side of the groove.

7. The dental implant fixture according to claim 6 , wherein an end portion on the rear end side of the small groove portion is located closer to the tip end side than an end portion on the tip end side of the bevel.

8. The dental implant fixture according to claim 1 , wherein the main body portion has a region where the large groove portion is located, the region having a smaller diameter toward the tip portion.

9. The dental implant fixture of claim 1 , wherein the groove comprises a first groove and a second groove spaced apart from each other.

10. 2. The dental implant fixture according to claim 1, wherein the tip portion is a portion that is located on the cancellous bone side of the alveolar bone when the dental implant fixture is embedded in a jawbone.

11. 2. The dental implant fixture according to claim 1, wherein the rear end portion is a portion that is located on the cortical bone side of the alveolar bone when the dental implant fixture is embedded in a jawbone.

12. A dental implant comprising: a dental implant fixture according to any one of claims 1 to 11; and a structural component attached to the rear end of the body portion of the dental implant fixture.

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