Dental implant fixture and dental implant

Abstract

To provide a dental implant fixture and a dental implant capable of maintaining apatite orientation in a regenerating cortical bone.SOLUTION: A dental implant fixture 1A comprises a small groove part 4, and the small groove part includes a first sidewall portion located on a front end side and a second sidewall portion located on a rear end side. The first sidewall portion extends away from a first reference surface as it moves away from a first bottom, the second sidewall portion is parallel to the first reference surface or extends away from the first reference surface as it moves away from the first bottom, and an angle α formed between the first sidewall portion and the first reference surface is larger than an angle β formed between the second sidewall portion and the first reference surface. A dental implant including the dental implant fixture is provided.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

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

[0003] Patent Document 2 proposes a configuration in which a fixture has a thread on its outer peripheral portion and a groove extends along the thread. This fixture is configured such that bone tissue can grow inside the groove extending along the thread.

[0004] On the other hand, apatite, which is the main component of bone, is known to have crystallographic anisotropy (see, for example, Patent Documents 3 and Non-Patent Documents 1 and 2). For example, the apatite orientation in the mandible changes depending on the site in the mandible (see, for example, Non-Patent Document 2). Specifically, at the edge close to the tooth, the orientation in the chewing load direction is dominant, and in the bone body, the mesiodistal orientation is dominant.

[0005] Since such apatite orientation maintains the original mechanical function of bone, it is considered that if the apatite orientation is maintained when regenerating bone, bone regeneration will be accelerated and long-term bone quality maintenance will also be possible. In particular, it is desirable to maintain the apatite orientation in the cortical bone to be regenerated in the posterior part of the implant, which is likely to be loaded due to the attachment of the structural component.

[0006] However, in the conventional fixture as described in Patent Document 2, the above-described apatite orientation is not considered.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0008]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] One of the problems of the present invention is to provide a fixture for dental implants and a dental implant that can maintain the apatite orientation in the regenerated cortical bone.

Means for Solving the Problems

[0010] The dental implant fixture according to an embodiment of the present invention includes a columnar main body portion, a large groove portion located on the tip side of the main body portion among the outer peripheral portions of the main body portion, and at least one small groove portion located on the rear end side of the main body portion among the outer peripheral portions. The at least one small groove portion has 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 away from a first reference plane perpendicular to the central axis of the main body portion through the first bottom portion as it moves away from the first bottom portion. The second side wall portion extends parallel to the first reference plane or away from the first reference plane as it moves away from the first bottom portion. In a cross-sectional view parallel to the central axis, an angle α formed by the first side wall portion and the first reference plane is larger than an angle β formed by the second side wall portion and the first reference plane.

[0011] The dental implant according to an embodiment of the present invention includes the dental implant fixture according to the above-described embodiment and a structural component attached to the rear end portion of the main body portion of the dental implant fixture.

Advantages of the Invention

[0012] According to the dental implant fixture according to an embodiment of the present invention, there is an effect that the apatite orientation in the regenerated cortical bone can be maintained.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

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

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

[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. When the fixture 1A is implanted into the jawbone 110, the front portion 231 is a portion located in the cancellous bone 113. Further, when the fixture 1A is implanted into the jawbone 110, the rear portion 232 is a portion located in the cortical bone 112. In the present embodiment, the area of the front portion 231 is larger than the area of the rear portion 232. Further, the front portion 231 is configured in a tapered shape that becomes smaller in diameter toward the tip portion 21 from the vicinity of the central portion thereof.

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

[0018] The large groove portion 3 is a so-called body thread. The large groove portion 3 of the present embodiment is located spirally in the front portion 231. In other words, the large groove portion 3 of the present embodiment extends spirally on the tip portion 21 side. According to such a configuration, the fixture 1A can be screwed into the alveolar bone 111 by self-tapping while being implanted. Note that the large groove portion 3 of the present embodiment is located over the entire circumference of the front portion 231. Therefore, when the fixture 1A is implanted into the alveolar bone 111, the large groove portion 3 is located in the cancellous bone 113.

[0019] On the one hand, as shown in FIGS. 10(b) and (c), the small groove portion 4 is a so-called microthread that functions as a site for regenerating the cortical bone 112 inside it. The small groove portion 4 is a site where the groove width and groove depth are substantially smaller than those of the large groove portion 3 described above. The groove width means the dimension of a straight line connecting the edges facing each other at the opening of the groove portion (the large groove portion 3 or the small groove portion 4). The groove depth means 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 is, as shown in FIG. 1, an axis that penetrates between the tip end portion 21 and the rear end portion 22 of the main body portion 2, and means an axis that becomes the rotation axis when the fixture 1A is rotated.

[0020] The small groove portion 4 of the present embodiment is spirally located in the rear portion 232. In other words, the small groove portion 4 of the present embodiment extends spirally on the rear end portion 22 side. Further, the small groove portion 4 of the present embodiment is located over the entire circumference of the rear portion 232. The small groove portion 4 of the present embodiment is a so-called double thread of the first small groove portion 4A and the second small groove portion 4B that are spaced apart from each other as shown in FIG. 2. Note that the number of the small groove portions 4 is preferably 1 to 4. When the number of the small groove portions 4 is plural, the configurations of the plural small groove portions 4 may be the same as each other or different from each other. In the present embodiment, since the first small groove portion 4A and the second small groove portion 4B have substantially the same configuration, hereinafter, the description of the first small groove portion 4A will be used instead of the description of the second small groove portion 4B. Also, there may be cases where the description of the first small groove portion 4A is given by attaching reference numerals to the second small groove portion 4B.

[0021] The first small groove portion 4A of the present 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 a region where the groove depth is the largest in the first small groove portion 4A. Further, 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 the present 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 portion 42 extends so as to move away from the first reference plane S2 as it moves away from the first bottom portion 41, in other words, as it moves outward in the direction of arrow A from the first bottom portion 41. Further, the second side wall portion 43 extends so as to move away from the first reference plane S2 as it moves away from the first bottom portion 41. And in a cross-sectional view parallel to the central axis S1 shown in FIG. 2, the angle α formed by the first side wall portion 42 and the first reference plane S2 is larger than the angle β formed by the second side wall portion 43 and the first reference plane S2. In other words, the angles α and β have a relationship of α>β. According to such a configuration, the cortical bone 112 can be induced and regenerated inside the first small groove portion 4A while maintaining the apatite orientation, and therefore it can be expected that bone regeneration will be accelerated and long-term bone mass maintenance will be possible.

[0023] Here, the following experiment was conducted regarding the relationship between the magnitudes of the angles α and β. That is, a fixture was implanted in the tibia of a rabbit, and an in vivo experiment with repeated loading was performed. Then, histological analysis based on bone area ratio and bone contact ratio, and three-dimensional structural analysis using indices such as BVF, Tb.N, Tb.Th, Tv.Sp, and BMD were performed. Furthermore, the number of bone cells generated in the groove portion and the apatite orientation were examined. As a result, in the groove portion where α>β, an increase in the amount of newly formed bone and a larger number of bone cells were obtained compared to the groove portion where α<β. Although the orientation of apatite was observed along the side wall portion in both groove portions with different relationships, it was found that α>β is superior to α<β from the viewpoints of bone mass and bone quality.

[0024] Note that the above-mentioned outward direction means the outside of the fixture 1A with respect to the first bottom portion 41 and the direction opposite to the inward direction on the central axis S1 side. The above-mentioned first reference plane S2 means a plane passing through the first bottom portion 41 and perpendicular to the central axis S1 of the main body portion 2.

[0025] Both of the above-described angle α and angle β are acute angles. As the angle α, it is preferably 40 to 65°, more preferably 45 to 60°. As the angle β, it is preferably 1 to 15°, more preferably 5 to 10°.

[0026] In the present embodiment, in the above-described cross-sectional view, among the edge portions 46a and 46b facing each other at the opening 46 of the first small groove portion 4A, the edge portion 46a located on the second side wall portion 43 side is a curved shape convex outward. According to such a configuration, it is possible to suppress bone resorption.

[0027] In the present embodiment, from the viewpoint of inducing and regenerating the cortical bone 112 inside the first small groove portion 4A while maintaining the apatite orientation, it has the following configuration. That is, in the above-described 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 side than the second connection portion 45 of the first bottom portion 41 and the second side wall portion 43. Also, in the above-described cross-sectional view, the length L42 of the first side wall portion 42 is larger than the length L43 of the second side wall portion 43. In the present embodiment, as described above, the edge portion 46a of the first small groove portion 4A is a curved shape convex outward. In the present 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 on the side closer to the first bottom portion 41.

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

[0029] As described above, the first bottom portion 41 of the present embodiment is curved and convex inward in the cross-sectional view described above. Examples of the curved shape include a parabolic shape, an elliptical arc shape, and an arc shape. The first bottom portion 41 of the present embodiment is an arc shape that is convex inward in the cross-sectional view described above. More specifically, the first bottom portion 41 of the present embodiment is an arc shape that is convex inward and has its center O in the following specific positional relationship.

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

[0031] With respect to the first straight line L1 and the second straight line L2 described above, the center O of the first bottom portion 41 has the following positional relationships (i) and (ii). (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-described configuration, among the above-described effects due to the first bottom portion 41 being curved and convex inward, the effect of being able to increase the surface area and volume of the first small groove portion 4A while maintaining the strength of the first small groove portion 4A can be improved. In addition, capillaries with a diameter of several hundred micrometers can penetrate to the first bottom portion 41. Therefore, the amount of newly formed bone can be increased, and an improvement in the contact rate between the bone and the fixture 1A can be expected.

[0033] In the cross-sectional view described above, in the first small groove portion 4A of the present embodiment, the groove width W at the opening portion 46 is larger than the groove depth D. According to such a configuration, it becomes easier to guide the cortical bone 112 into the first small groove portion 4A while maintaining the apatite orientation. In the present embodiment, as described above, the edge portion 46a of the first small groove portion 4A has a curved shape convex outward. In the present 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 the present embodiment, the large groove portion 3 described above has substantially the same configuration as the small groove portion 4. That is, as shown in FIG. 3, the large groove portion 3 of the present 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 end 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. Similar to the first side wall portion 42 of the small groove portion 4, the third side wall portion 32 extends away from the second bottom portion 31 and away from the second reference plane S3 perpendicular to the central axis S1 passing through the second bottom portion 31. Also, as described above, in the present embodiment, since the second side wall portion 43 of the small groove portion 4 extends away from the first reference plane S2 as it moves away from the first bottom portion 41, the fourth side wall portion 33 of the large groove portion 3 also extends away from the second reference plane S3 as it moves away from the second bottom portion 31. And, in a cross-sectional view parallel to the central axis S1 shown in FIG. 3, the angle γ formed by the third side wall portion 32 and the second reference plane S3 is larger than the angle δ formed by the fourth side wall portion 33 and the second reference plane S3. In other words, the angles γ and δ have a relationship of γ > δ. According to such a configuration, since the change in the configuration from the large groove portion 3 to the small groove portion 4 can be reduced, the embeddability when embedding the fixture 1A into 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 osteonecrosis can be suppressed. Also, the inhibitory factors when guiding and regenerating the cortical bone 112 into the small groove portion 4 while maintaining the apatite orientation can be reduced. Furthermore, bone remodeling can be promoted. Note that the configuration of the large groove portion 3 is not limited to being substantially the same as that of the small groove portion 4 as long as its function can be achieved.

[0035] In this embodiment, the angle α of the first side wall portion 42 in the small groove portion 4 described above is larger than the angle γ of the third side wall portion 32 in the large groove portion 3. Also, the angle β of the second side wall portion 43 in the small groove portion 4 described above and the angle δ of the fourth side wall portion 33 in the large groove portion 3 are the same. That is, in this embodiment, the angle α and the angle γ have a relationship of α > γ, and the angle β and the angle δ have a relationship of β = δ. According to these configurations, the embeddability when embedding the fixture 1A into the alveolar bone 111 tends to be improved. In this embodiment, the angle α is set to 50°, the angle β is set to 10°, the angle γ is set to 45°, and the angle δ is set to 10°, but it is not limited thereto. Also, the fact that the angle β and the angle δ are the same means that it is sufficient if the angles of both are substantially the same. This point is the same in the embodiments described later.

[0036] The fixture 1A of the present embodiment described above is preferably manufactured by a layered manufacturing method. Thereby, the fixture 1A can be obtained with excellent machining accuracy. Note that the manufacturing method of the fixture 1A is not limited to the layered manufacturing method as long as the fixture 1A can be obtained. As other manufacturing methods of the fixture 1A, for example, cutting processing and the like can be mentioned.

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

[0038] As shown in Fig. 4, in the fixture 1B of the present embodiment, the second side wall portion 43 in the small groove portion 4 extends parallel to the first reference plane S2. In other words, in the fixture 1B of the present embodiment, the angle β formed by the second side wall portion 43 and the first reference plane S2 described above is 0°. And the angle α and the angle β have the relationship of α > β. According to such a configuration, it becomes easier to guide the cortical bone 112 into the small groove portion 4 while maintaining the apatite orientation. Note that the second side wall portion 43 only needs to extend substantially parallel to the first reference plane S2.

[0039] As shown in Fig. 5, in the fixture 1B of the present embodiment, the large groove portion 3 has substantially the same configuration as the small groove portion 4. That is, in the present 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 formed by the fourth side wall portion 33 and the second reference plane S3 is 0°. And the angle γ and the angle δ have the relationship of γ > δ. According to such a configuration, similar to the first embodiment described above, since the change in the configuration from the large groove portion 3 to the small groove portion 4 can be reduced, the embeddability when embedding the fixture 1B into 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 osteonecrosis can be suppressed. Also, the inhibitory factors when inducing and regenerating the cortical bone 112 into the small groove portion 4 while maintaining the apatite orientation can be reduced. Furthermore, bone remodeling can be promoted. Note that the fourth side wall portion 33 only needs to extend substantially parallel to the second reference plane S3.

[0040] In the present embodiment, the angle α of the first side wall portion 42 in the small groove portion 4 described above and the angle γ of the third side wall portion 32 in the large groove portion 3 are the same. That is, in the present embodiment, the angle α and the angle γ have the relationship of α = γ. According to such a configuration, the embeddability when embedding the fixture 1B into the alveolar bone 111 tends to be improved. Note that in the present embodiment, both the angle α and the angle γ are set to 45°, but it is not limited thereto. Since the other configurations are the same as those of the fixture 1A according to the first embodiment described above, the description thereof will be omitted.

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

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

[0043] In the present embodiment, the portion of the outer peripheral portion 23 where the large groove portion 3 is located is configured in a tapered shape that becomes smaller in diameter from the vicinity of its central portion toward the tip portion 21. Also, the area of the portion of the outer peripheral portion 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 groove portion 4 of the present embodiment is a so-called double thread of a first small groove portion 4A and a second small groove portion 4B, the number of which is two and are spaced apart from each other. In the present embodiment, the first small groove portion 4A and the second small groove portion 4B have substantially the same configuration.

[0045] Here, in the present embodiment, both the large groove portion 3 and the small groove portion 4 extend spirally. According to such a configuration, it is possible to reduce the insertion resistance when the fixture 1C is inserted into the alveolar bone 111.

[0046] In addition, in the present embodiment, at the boundary portion 5 between the large groove portion 3 and the small groove portion 4, a portion 31 located on the rear end portion 22 side in the large groove portion 3 and a portion 47 located on the front end portion 21 side in the small groove portion 4 are parallel to each other. According to such a configuration, when the fixture 1C is embedded in the alveolar bone 111 in the order of the large groove portion 3 and the small groove portion 4, at the boundary portion 5 between the large groove portion 3 and the small groove portion 4, since the configuration gradually switches from the large groove portion 3 to the small groove portion 4, it is possible to keep the embedding resistance constant when the fixture 1C is embedded in the alveolar bone 111. Further, at the boundary portion 5 between the large groove portion 3 and the small groove portion 4, since the area of the portion of the outer peripheral portion 23 of the main body portion 2 where the large groove portion 3 and the small groove portion 4 do not exist is reduced, it is possible to reduce the embedding resistance when the fixture 1C is embedded in the alveolar bone 111. And, combined with these effects and the effect of the above-described large groove portion 3 and small groove portion 4 both extending in a spiral shape, an effect that the fixture 1C can be easily embedded in the alveolar bone 111 is obtained. As a result, the occurrence of osteonecrosis can be suppressed. Further, it is possible to reduce the inhibitory factors when inducing and regenerating the cortical bone 112 inside the small groove portion 4 while maintaining the apatite orientation. Furthermore, bone remodeling can be promoted.

[0047] Note that, as shown in FIG. 6(b), the boundary portion 5 between the large groove portion 3 and the small groove portion 4 means a region including an end portion 48 located on the front 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. Further, in FIG. 6(b), the line indicating the large groove portion 3 represents the second bottom portion 31 (see FIGS. 3 and 5) of the large groove portion 3. This is the same for the small groove portion 4. That is, in FIG. 6(b), the line indicating the small groove portion 4 represents the first bottom portion 41 (see FIGS. 2 and 4) of the small groove portion 4.

[0048] That the part 31 of the large groove part 3 and the part 47 of the small groove part 4 are running parallel to each other means that the parts 31 and 47 are extending in a state of being arranged side by side with each other. The parts 31 and 47 may run parallel to each other while being separated from each other, or may run parallel to each other in a state of partially merging. Partially merging means that a part of the part 31 and a part of the part 47 are merging with each other within the range where the parts 31 and 47 can each perform their functions. In the present embodiment, as shown in FIGS. 7 and 8, the parts 31 and 47 are running parallel to each other in a state of partially merging. According to such a configuration, it becomes possible to smoothly switch the configuration from the large groove part 3 to the small groove part 4.

[0049] As shown in FIG. 6, in the present embodiment, at the boundary part 5 between the large groove part 3 and the small groove part 4, the part 31 of the large groove part 3 and the part 47 of the small groove part 4 are running parallel to each other in the following state. That is, in the present embodiment, the part 47a of the part 47 of the small groove part 4 where the groove depth D4 is the largest is located at the substantially central part of the boundary part 5 between the large groove part 3 and the small groove part 4, and the parts 31 and 47 are running parallel to each other.

[0050] Also, in the present embodiment, the part 31 of the large groove part 3 and the part 47 of the small groove part 4 are running parallel to each other in a state where the angle θ1 formed by the reference line S4 parallel to the central axis S1 and the part 31 of the large groove part 3 is larger than the angle θ2 formed by the reference line S4 and the part 47 of the small groove part 4. In other words, in the present embodiment, the angle θ1 is larger than the angle θ2. That is, in the present embodiment, the angle θ1 and the angle θ2 have a relationship of θ1 > θ2.

[0051] Both the angle θ1 and the angle θ2 are preferably acute angles. According to such a 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 reaches the end portion 32 that is gradually 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. Therefore, 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] Also, in the present embodiment, the groove depth D3 of the portion 31 of the large groove portion 3 decreases toward the rear end portion 22 side, and the groove depth D4 of the portion 47 of the small groove portion 4 increases toward the rear end portion 22 side. Also by such a 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 the largest. Therefore, 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 portion 2 of the present embodiment further has a bevel 6 located on the rear end portion 22 side. When the fixture 1C is viewed from a direction perpendicular to the central axis S1, the bevel 6 of the present embodiment is a substantially trapezoidal shape with the tip end portion 21 side as the long side 61. Further, as shown in FIG. 11(c) described later, the bevel 6 is a portion exposed from the cortical bone 112 when the fixture 1C is embedded in the alveolar bone 111. Since the above-described long side 61 of the bevel 6 is located at the boundary between the cortical bone 112 and the gingiva 101, it constitutes the bone edge line L.

[0054] Here, in the present embodiment, as shown in FIG. 7, the end portion 49 located on the rear end portion 22 side of the small groove portion 4 is located on the front end portion 21 side of the bone edge line L located on the rear end portion 22 side of the outer peripheral portion 23. According to such a configuration, excellent sealing performance can be exhibited, and the strength of the fixture 1C itself can be improved. Further, in the present embodiment, the end portion 49 of the small groove portion 4 is located in the vicinity of the bone edge line L. According to such a configuration, a large area of the small groove portion 4 can be secured. As shown in FIG. 6(b), the small groove portion 4 of the present embodiment has a groove depth D4 that decreases toward the end portion 49 side. Other configurations are the same as those of the fixtures 1A and 1B according to the above-described first and second embodiments, and thus the description thereof is omitted.

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

[0056] As shown in FIG. 9, the dental implant 10 of the present embodiment includes the above-described 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 examples thereof include those made of metal, ceramic, hard resin, and the like. The artificial tooth 11 is usually made to order and is attached to the rear end portion 22 of the fixture 1A via an abutment 12. The artificial tooth 11 may be of a single type or a connected type (bridge). Instead of the artificial tooth 11, other artificial teeth can also be adopted as structural components. Examples of other artificial teeth include dentures. Examples of dentures include so-called inserted teeth such as partial dentures or complete dentures. The inserted teeth are attached to the rear end portion 22 of the fixture 1A via an attachment in a removable state.

[0058] In the present embodiment, the case of using the fixture 1A has been described as an example. However, even if the fixtures 1B and 1C are used instead of the fixture 1A, a dental implant having the same effect can be obtained.

[0059] <Dental implant placement surgery> (First Embodiment) Next, regarding the dental implant placement surgery according to the first embodiment of the present invention, taking the case of using the fixture 1A according to the above-described first embodiment as an example, it will be described in detail with reference to FIG. 10.

[0060] First, as shown in FIG. 10(a), an implantation hole 100 is drilled in the alveolar bone 111 of the gingiva 101 and the jawbone 110 using a drill or the like. The implantation hole 100 of the present embodiment has a shape slightly smaller than that of the fixture 1A.

[0061] Next, as shown in FIG. 10(b), the fixture 1A is implanted into the drilled implantation hole 100. After a non-loading period of several weeks to several months, the cortical bone 112 regenerates inside the small groove portion 4. In the present embodiment, as described above, since 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, the cortical bone 112 is induced and regenerated inside the small groove portion 4 while maintaining the apatite orientation. Therefore, according to the present embodiment, it can be expected that bone regeneration is fast and long-term bone quality maintenance is also possible.

[0062] During the non-loading period, in order to protect the gingiva 101, it is preferable to attach the healing cap 13 to the rear end portion 22 as shown in FIG. 10(b). After the fixation of the fixture 1A to the jawbone 110 is completed, as shown in FIG. 10(c), the healing cap 13 is removed from the rear end portion 22, and structural components such as the artificial tooth 11 described above are attached to the rear end portion 22 to form a dental implant, and the treatment is terminated.

[0063] (Second Embodiment) Next, regarding the dental implant placement surgery according to the second embodiment of the present invention, taking the case of using the fixture 1C according to the above-described third embodiment as an example, it will be described in detail with reference to FIG. 11. In FIG. 11, the same components as those in FIG. 10 described above may be denoted by the same reference numerals and the description thereof may be omitted.

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

[0065] Next, as shown in FIG. 11(b), the fixture 1C is implanted into the drilled implantation hole 100. In the present embodiment, as described above, both the large groove portion 3 and the small groove portion 4 extend spirally, and at the boundary portion 5 between the large groove portion 3 and the small groove portion 4, a portion 31 located on the rear end portion 22 side of the large groove portion 3 and a portion 47 located on the front end portion 21 side of the small groove portion 4 are parallel to each other. Therefore, the fixture 1C can be smoothly implanted into the implantation hole 100 (alveolar bone 111). As a result, the occurrence of bone necrosis can be suppressed. In addition, the inhibitory factors when inducing and regenerating the cortical bone 112 inside the small groove portion 4 while maintaining the apatite orientation can be reduced. Furthermore, bone remodeling can be promoted.

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

[0067] In the above-described first and second embodiments, the cases of using the fixtures 1A and 1C have been described as examples. However, the same effects 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, The large groove portion is A second bottom portion; a third side wall portion connected to one end of the second bottom portion; a fourth side wall portion connected to the other end of the second bottom portion and located closer to the rear end portion than the third side wall portion, In a second cross-sectional view including a cross-section of the large groove portion, an angle γ between the third side wall portion and a second reference plane that passes through the second bottom portion and is perpendicular to a central axis of the main body portion is greater than an angle δ between the fourth side wall portion and the second reference plane.

2. the small groove portion has a first bottom portion, a first sidewall portion connected to one end of the first bottom portion, and a second sidewall portion connected to the other end of the first bottom portion and located closer to the rear end portion than the first sidewall portion; 2. The dental implant fixture according to claim 1, wherein, in a first cross-sectional view including a cross-section of the small groove portion, an angle α between the first side wall portion and a first reference plane that passes through the first bottom portion and is perpendicular to a central axis of the main body portion is greater than an angle β between the second side wall portion and the first reference plane.

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

4. The dental implant fixture according to claim 1 , comprising a boundary portion where the large groove portion and the small groove portion run side by side while partially merging.

5. The dental implant fixture according to claim 4 , 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.

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

7. The dental implant fixture according to claim 4 , 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.

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

9. The dental implant fixture according to claim 8 , wherein an end portion on the rear end side of the small groove is located closer to the tip end side than an end portion on the tip end side of the bevel.

10. 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.

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

12. 3. The dental implant fixture of claim 2, wherein a first connection portion between the first bottom and the first side wall is located closer to the central axis than a second connection portion between the first bottom and the second side wall, the first bottom is arc-shaped, and when a straight line connecting the opposing edges of the groove portion is defined as a first straight line and a straight line passing through the midpoint of the first straight line and perpendicular to the central axis is defined as a second straight line, the center of the arc in the first bottom is located closer to the central axis than the first straight line and closer to the rear end portion than the second straight line.

13. 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.

14. 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.

15. A dental implant comprising: a dental implant fixture according to any one of claims 1 to 14; and a structural component attached to the rear end of the body portion of the dental implant fixture.

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