JP7511925B1 - Denture system and implant for use in the denture system - Google Patents

Abstract

[Problem] To reduce external forces acting on an implant. [Solution] A denture system includes an implant and a prosthesis attached to the implant. The implant includes a fixture portion to be embedded in the alveolar bone, and an abutment portion fixed to the fixture portion and having an exposed portion exposed from the gums covering the alveolar bone. The prosthesis is provided with an engagement hole with which the exposed portion engages. An elastic body is disposed between the outer peripheral surface of the exposed portion and the inner peripheral surface of the engagement hole. The elastic body includes a first elastic portion that is disposed at a height between a base end, which is the end of the exposed portion on the fixture portion side, and a tip end, which is the end on the opposite side to the fixture portion, when the exposed portion engages with the engagement hole, and a second elastic portion that is disposed between the tip end of the exposed portion and the bottom of the engagement hole when the exposed portion engages with the engagement hole. [Selected Figure] Figure 3

Description

The technology disclosed in this specification relates to denture systems and implants for use in denture systems.

Patent Document 1 discloses a denture system that is installed in the oral cavity. This denture system includes an implant and a prosthesis that is attached to the implant. The implant includes a fixture portion that is embedded in the alveolar bone, and an abutment portion that is fixed to the fixture portion. The abutment portion has an exposed portion that is exposed from the gums that cover the alveolar bone. The prosthesis is provided with an engagement hole with which the exposed portion can engage. When the prosthesis is attached to the abutment portion, the exposed portion is inserted into the engagement hole of the prosthesis, and the two are engaged.

Patent No. 5100918

In this type of denture system, an external force acts on the prosthesis when the wearer eats food, and as a result, an external force acts from the prosthesis to the implant, and as a reaction, an external force acts from the implant to the prosthesis. This results in repeated external forces acting on the implant and prosthesis. If a large external force acts repeatedly on the implant and prosthesis, it can cause the implant and prosthesis to break, the bond between the implant and the alveolar bone (osseointegration) to be destroyed, or the alveolar bone itself to be damaged. This specification provides a technology that can artificially reproduce the action of the periodontal ligament and reduce the external forces acting on the implant and prosthesis, and also allows the wearer of the prosthesis to obtain a chewing sensation closer to that of natural teeth.

The denture system disclosed in this specification includes an implant and a prosthesis attached to the implant. The implant includes a fixture portion embedded in the alveolar bone and an abutment portion fixed to the fixture portion. The abutment portion has an exposed portion exposed from the gums covering the alveolar bone. The prosthesis is provided with an engagement hole with which the exposed portion engages. An elastic body is disposed between the outer peripheral surface of the exposed portion and the inner peripheral surface of the engagement hole. The elastic body includes a first elastic portion disposed at a height between the base end, which is the end of the exposed portion on the fixture portion side, and the tip end, which is the end on the opposite side to the fixture portion, when the exposed portion engages with the engagement hole, and a second elastic portion disposed between the tip end of the exposed portion and the bottom of the engagement hole when the exposed portion engages with the engagement hole.

In the above denture system, an elastic body is disposed between the implant and the prosthesis. Therefore, when an external force acts on the prosthesis, the external force acts on the implant via the elastic body. The elastic body includes a first elastic part disposed at a height between the base end and the tip end of the exposed part, and a second elastic part disposed between the tip end of the exposed part and the prosthesis. Therefore, even if an external force acts on the prosthesis from various directions, the external force acting from the prosthesis to the implant, and the external force acting from the implant to the prosthesis as a reaction thereto, are suitably distributed. As a result, the application of a large external force locally to the implant and the prosthesis is suppressed, and the external force acting on the implant and the prosthesis can be reduced and distributed.
In addition, this denture system artificially reproduces the same effect as the periodontal ligament in natural teeth, allowing the prosthesis wearer to obtain a more natural chewing sensation that is closer to that of natural teeth.

This specification also discloses an implant suitable for use in the above-mentioned denture system. This implant includes a fixture portion to be embedded in the alveolar bone, an abutment portion to be fixed to the fixture portion, and an elastic body attached to the outer peripheral surface of the exposed portion. The abutment portion has an exposed portion that is exposed from the gums that cover the alveolar bone. The prosthesis is provided with an engagement hole with which the exposed portion can engage. The elastic body is disposed between the outer peripheral surface of the exposed portion and the inner peripheral surface of the engagement hole. Furthermore, the elastic body includes a first elastic portion that is disposed at a height between the base end, which is the end of the exposed portion on the fixture portion side, and the tip end, which is the end on the opposite fixture portion side, when the exposed portion engages with the engagement hole, and a second elastic portion that is disposed between the tip end of the exposed portion and the bottom of the engagement hole when the exposed portion engages with the engagement hole.

A schematic cross-sectional view of the denture system disclosed in this specification as viewed from the labial/cheek side, the cross-sectional view passing through the central axis of the fixture. FIG. 2 is a plan view of the prosthesis when placed in the oral cavity. 1 is an enlarged view showing the implant body of Example 1, an elastic body attached to the implant body, and a cap embedded in the prosthesis. FIG. 4 is a diagram showing a schematic diagram of the implant body, the elastic body, and the cap shown in FIG. 3 in an engaged state. FIG. FIG. 13 is an enlarged view showing an implant body of a second embodiment, an elastic body attached to the implant body, and a cap embedded in a prosthesis. 6 is a diagram showing a schematic diagram of the implant body, the elastic body, and the cap shown in FIG. 5 in an engaged state.

In the denture system disclosed herein, the elastic body may be formed of a material different from that of the abutment portion. The elastic modulus of the elastic body may be smaller than that of the abutment portion.

In the denture system disclosed in this specification, the first elastic part may be attached to one of the outer peripheral surface of the exposed part and the inner peripheral surface of the engagement hole. A groove with which the first elastic part can engage may be provided on the other of the outer peripheral surface of the exposed part and the inner peripheral surface of the engagement hole. The prosthesis may be configured such that the exposed part is inserted into the engagement hole and the first elastic part engages with the groove, thereby engaging the exposed part with the engagement hole and attaching the prosthesis to the abutment part.

In the denture system disclosed in this specification, the first elastic portion has a ring shape that extends circumferentially along the outer peripheral surface of the exposed portion and goes around the exposed portion, and may be removably attached to the outer peripheral surface of the exposed portion.

In the denture system disclosed in this specification, the prosthesis may be removably attached to the abutment portion. The engagement structure between the first elastic portion and the groove may be configured to increase the force required to remove the prosthesis from the abutment portion.

In the denture system disclosed herein, a recess may be formed in the distal end of the exposed portion. The second elastic portion may be attached to the distal end of the exposed portion by engaging a portion of the second elastic portion within the recess.

In the denture system disclosed in this specification, in a first state in which the prosthesis is attached to the abutment portion and no external force acts on the prosthesis, a first clearance may be provided between the second elastic body and the inner peripheral surface of the engagement hole, and a second clearance may be provided between the outer peripheral surface of the exposed portion and the inner peripheral surface of the engagement hole.

In the denture system disclosed in this specification, in the first state, the second clearance is provided on the entire outer peripheral surface of the exposed portion and the entire inner peripheral surface of the engagement hole, and the outer peripheral surface of the exposed portion and the inner peripheral surface of the engagement hole may not be in contact with each other. In the first state, the first clearance is provided on the entire surface of the second elastic body that faces the inner peripheral surface of the engagement hole, and the second elastic body and the inner peripheral surface of the engagement hole may not be in contact with each other.

Example 1
A denture system 1 of Example 1 will be described. As shown in FIG. 1, the denture system 1 includes a prosthesis 10 and implants (16, 18). The prosthesis 10 includes a prosthesis 12 for the mandible and a prosthesis 14 for the maxilla. The surface of the alveolar bone 22 of the mandible is covered with gums 24. The surface of the alveolar bone 26 of the maxilla is covered with gums 28. The implants (16, 18) include a fixture 16 and an abutment 18 fixed to the fixture 16. Four fixtures 16 are embedded in the alveolar bone 22 of the mandible and the alveolar bone 26 of the maxilla, penetrating the gums 24, 28. The central axes of the fixture 16 and the abutment 18 are aligned. The height of the connection surface of the fixture 16 and the abutment 18 is equal to the height of the surfaces of the alveolar bones 22, 26 (bone level implant). A portion of the abutment 18 is exposed from the gums 24, 28. Hereinafter, the exposed portion will be referred to as an exposed portion 20.

As shown in FIG. 1, prostheses 12 and 14 are prostheses for an edentulous jaw (full prostheses). In this specification, "edentulous jaw" refers to a jaw in which no natural tooth crowns remain. For this reason, even if natural tooth roots remain in the alveolar bone, if no natural tooth crowns remain, the jaw is classified as "edentulous." Prosthesis 12 is attached on the gums 24 of the mandible, and prosthesis 14 is attached on the gums 28 of the maxilla.

The prosthesis 12 includes 14 artificial teeth 30-56 and a base 58. The artificial teeth 30-56 are made of porcelain or the like. The artificial teeth 30-56 mimic the appearance of natural teeth and are arranged in the same manner as natural teeth. Specifically, the first artificial tooth 30, 44 from the midline L1 functions as a central incisor, the second artificial tooth 32, 46 as a lateral incisor, the third artificial tooth 34, 48 as a canine, the fourth artificial tooth 36, 50 as a first premolar, the fifth artificial tooth 38, 52 as a second premolar, the sixth artificial tooth 40, 54 as a first molar, and the seventh artificial tooth 42, 56 as a second molar. The material of the artificial teeth 30-56 is not limited to porcelain, and may be, for example, zirconia, a hybrid, a hard resin, or a polyamide-based material (e.g., nylon, etc.).

The base 58 is made of a polyamide-based material, for example, nylon. Nylon is a highly durable, lightweight, and highly elastic material, and has a Young's modulus of 70 to 267 kgf/mm ^-2 . The base 58 mimics the appearance of natural gums, and is bonded to the lower side (i.e., the alveolar bone 22 side) of the artificial teeth 30 to 56. The base 58 is provided with four engagement holes 59 at positions corresponding to the exposed portions 20 of the abutments 18, which can engage with the exposed portions 20. More specifically, the engagement holes 59 are formed by caps 110 (shown in FIG. 3) embedded in the base 58, and the caps 110 are embedded in the base 58 located below the canines 34 and 48 and the base 58 located below the first molars 40 and 54. By engaging the exposed portion 20 of the abutment 18 with the engagement hole 59, the prosthesis 12 is placed in the wearer's oral cavity (i.e., the prosthesis 12 is fixed to the gums 24). At this time, the lower surface 58a of the base 58 is in contact with the surface 24a of the gums 24 (hereinafter, the lower surface of the base 58 will be referred to as the "contact surface"). The prosthesis 12 is configured to be detachable from the abutment 18 by the wearer engaging or detaching the exposed portion 20 with the engagement hole 59.

The prosthesis 14 has a configuration substantially the same as that of the prosthesis 12. That is, the prosthesis 14 includes 14 artificial teeth 60-86 and a base 88. The names of the artificial teeth when counted from the midline L1 are the same as the artificial teeth 30-56 of the prosthesis 12. The base 88 is bonded above the artificial teeth 60-86 (i.e., on the alveolar bone 26 side). The base 88 is provided with four engagement holes 89 that can engage with the exposed portion 20 on each of the base 88 located above the canines 64, 78 and the gums 88 located above the first molars 70, 84. When the exposed portion 20 is engaged with the engagement holes 89, the prosthesis 14 is fixed to the gums 28. At this time, the upper surface 88a of the base 88 is in contact with the upper surface 28a of the gums 28. The prosthesis 14 is configured to be detachable from the abutment 18 by the wearer engaging and detaching the exposed portion 20 with the engagement hole 89. The position where the engagement hole 89 is provided (i.e., the position where the cap 110 is embedded (the position where the fixture 16 is embedded in the alveolar bone 26)) does not have to correspond to the position where the engagement hole 59 is provided. Furthermore, the positions and number of the engagement holes 59 and 89 are not limited to the above configuration and may be appropriately determined taking into account the wearer's biting force, etc.

Figure 2 is a plan view showing the prostheses 12, 14 placed in the oral cavity, with the plates 58, 88 shown in grayscale for ease of viewing. As shown in Figure 2, the artificial teeth 30, 32, 34, 44, 46, 48 in the anterior portion (1st to 3rd teeth) of the prosthesis 12 each have an incisal edge 30a, 32a, 34a, 44a, 46a, 48a at the tip of the crown. The artificial teeth 36, 38, 40, 42, 50, 52, 54, 56 in the molar portion (4th to 7th teeth) of the prosthesis 12 each have an occlusal surface 36a, 38a, 40a, 42a, 50a, 52a, 54a, 56a, respectively.

Here, the dashed line B1 in Figure 2 represents the boundary between the gingiva 24 and the alveolar mucosa 25 (i.e., the gingival-alveolar mucosal junction). The gingiva 24 is immobile and covered with keratinized epithelium, while the alveolar mucosa 25 is covered with non-keratinized mobile mucosa. As shown in Figure 2, the outer edge of the tongue side of the plate 58 is located closer to the labial/cheek side than the gingival-alveolar mucosal junction B1.

Each artificial tooth 60-86 of the prosthesis 14 also has an incisal edge 60a-64a, 74a-78a and an occlusal surface 66a-72a, 80a-86a. The outer edge of the palatal side of the base 88 is located on the labial/cheek side of the boundary line B2 between the gums 28 and the alveolar mucosa 29 (i.e., the gingival/alveolar mucosa boundary).

In this embodiment, the outer edge of the base 58 is located closer to the labial/cheek side than the gingival/alveolar mucosal junction B1, and the outer edge of the base 88 on the palate side is located closer to the labial/cheek side than the gingival/alveolar mucosal junction B2. The bases 58, 88 do not come into contact with the alveolar mucosa 25, 29, which significantly reduces discomfort when the prosthesis is worn. On the other hand, since the bases 58, 88 do not come into contact with the alveolar mucosa 25, 29 and the contact area between the bases 58, 88 and the oral cavity surface is small, a relatively large external force (occlusal pressure) acts on the implants (16, 18).

Next, the structure for engaging the exposed portion 20 of the abutment 18 with the engagement hole 59 (i.e., the cap 110) of the prosthesis 12 will be described. Note that the structure for engaging the exposed portion 20 with the engagement hole 89 of the prosthesis 14 is the same as the structure for engaging the exposed portion 20 with the engagement hole 59, so only the structure for engaging the exposed portion 20 with the engagement hole 59 will be described. As shown in Figures 3 and 4, the implant (16, 18) of this embodiment includes a fixture 16, an abutment 18 fixed to the fixture 16, and an elastic ring 120 attached to the outer circumferential surface of the abutment 18.

The fixture 16 has a shape in which the diameter decreases from one end to the other end. In detail, the fixture 16 has a large diameter at the end on the abutment 18 side and a small diameter at the other end. A straight type fixture with a constant diameter can be used for the fixture 16. A screw groove is formed on the outer circumferential surface of the fixture 16, and the fixture 16 is screwed into the alveolar bone 22. By forming the screw groove in the fixture 16, the fixture 16 is firmly fixed to the alveolar bone 22. The fixture 16 is made of a titanium alloy. The titanium alloy is a material with high mechanical strength and has a Young's modulus of about 110 GPa. The material of the fixture 16 is not limited to the titanium alloy, and may be a material known as a dental implant, such as pure titanium, titanium-nickel alloy, or artificial sapphire (aluminum oxide (Al ₂ O ₃ )).

The abutment 18 is fixed to one end (the end on the large diameter side) of the fixture 16 so that its axis L2 coincides with the axis L2' of the fixture 16. The abutment 18 extends from the end on the alveolar bone 22 side (hereinafter sometimes referred to as the base end) toward the prosthesis 12 side. When the fixture 16 is fixed to the alveolar bone 22, the base end of the abutment 18 is located in the gums 24, and the other end side of the abutment 18 protrudes from the gums 24. That is, an exposed portion 20 is formed on the other end side of the abutment 18. The abutment 18 is made of a titanium alloy, like the fixture 16. Note that the material of the abutment 18 is not limited to a titanium alloy, and for example, pure titanium, zirconia, zirconia using titanium in the core, gold alloy, and other precious metals for casting can be suitably used. Furthermore, although the strength and durability are lower than those of the above metals, resins (e.g., resin, hybrid ceramic, polyamide, PEEK (polyether ether ketone resin), polyimide, polycarbonate, etc.) may be used depending on the case.

As shown in FIG. 3, the abutment 18 has a base end 102 that is inserted into the fixture 16 and a protruding portion 104 provided at the end of the base end 102 on the side opposite to the fixture. The base end 102 of the abutment 18 has a shape following an insertion hole provided in the fixture 16. When the base end 102 is inserted into the insertion hole of the fixture 16, the entire base end 102 is accommodated inside the fixture 16, and the protruding portion 104 protrudes from the tip of the fixture 16 toward the prosthesis 12 side. Therefore, the protruding portion 104 of the abutment 18 becomes the exposed portion 20. The protruding portion 104 has an approximately truncated cone shape, and a recess 108 that is concave toward the fixture 16 side is formed on the upper end surface of the protruding portion 104 (i.e., the tip surface of the exposed portion 20 of the abutment 18). The recess 108 is designed to allow an instrument for fixing the abutment 18 to the fixture 16 to be inserted. After the abutment 18 is fixed to the fixture 16, an elliptical elastic ball 122 (an example of a "second elastic portion") is attached to the recess 108. When the elastic ball 122 is attached to the recess 108, a part of the elastic ball 122 protrudes upward from the upper end surface of the protruding portion 104. As is clear from FIGS. 3 and 4, the opening width of the recess 108 is maximum inside the protruding portion 104, and is smaller at the upper end surface of the protruding portion 104 compared to the maximum part. Therefore, when the elastic ball 122 is attached to the recess 108, the elastic ball 122 is held within the recess 108 and is prevented from falling out of the recess 108. The elastic ball 122 can be attached to and detached from the recess 108 by applying an external force to the elastic ball 122 to elastically deform it. Therefore, the elastic ball 122 can be replaced for maintenance or the like.

3 and 4, a mounting groove 106 is formed on the side surface (the outer peripheral surface of the exposed portion 20) of the truncated cone-shaped protrusion 104. That is, the mounting groove 106 is formed at a height (approximately the middle position in this embodiment) between the base end, which is the end of the protrusion 104 on the fixture side, and the tip end, which is the end on the opposite side to the fixture. The mounting groove 106 extends in the circumferential direction along the outer peripheral surface of the protrusion 104, and goes around the periphery of the protrusion 104. The mounting groove 106 is provided symmetrically with respect to the axis L2 of the abutment 18. As is clear from FIGS. 3 and 4, the formation direction (extension direction) L3 of the mounting groove 106 is a direction that intersects with the axis L2. Specifically, it is a direction that extends obliquely upward from the base end side of the protrusion 104 toward the tip end side of the protrusion 104. In addition, since an elastic ring 120 (an example of a "first elastic portion") described later is attached to the mounting groove 106, the forming direction L3 of the mounting groove 106 can be said to be the mounting direction of the elastic ring 120. The shape of the mounting groove 106 is a shape that follows the shape of the elastic ring 120. As is clear from Figures 3 and 4, the outer diameter of the outer peripheral surface of the protrusion 104 above the mounting groove 106 (opposite the fixture side) is larger than the outer diameter below the mounting groove 106 (the fixture side). In other words, the outer peripheral surface located above the mounting groove 106 is offset outward from the outer peripheral surface located below the mounting groove 106.

In this embodiment, the abutment 18 and the fixture 16 are formed separately, but this is not limited to the configuration, and the abutment 18 and the fixture 16 may be formed integrally.

The elastic ring 120 is detachably attached to the mounting groove 106 of the abutment 18. The elastic ring 120 is formed of a material with high elasticity (i.e., a low Young's modulus). The Young's modulus of the elastic ring 120 is set lower than that of the abutment 18 and the bed 58. The material for forming the elastic ring 120 can be a material different from that of the abutment 18 and the bed 58. For example, the elastic ring 120 can be made of vulcanized rubber (nitrile rubber, hydrogenated nitrile rubber perfluoro, fluorosilicone rubber, fluororubber, chloroprene rubber, bruchi rubber, styrene butadiene rubber, silicone rubber, acrylic rubber, urethane rubber, aflas, ethylene propylene rubber, Teflon (registered trademark), Viton ETP, etc.). However, in addition to the vulcanized rubber described above, any known material used as a material for an O-ring can be used. The elastic ball 122 is also made of the same material as the elastic ring 120. Therefore, the Young's modulus of the elastic ball 122 is also lower than that of the abutment 18 and the base 58. In this embodiment, the elastic ball 122 and the elastic ring 120 are made of the same material, and the elastic modulus (e.g., Young's modulus) of the elastic ball 122 and the elastic modulus (e.g., Young's modulus) of the elastic ring 120 are the same, but this is not limited to this example. For example, the elastic modulus of the elastic ball 122 may be made larger than that of the elastic ring 120 to make the elastic ball 122 less susceptible to elastic deformation. As will be described later, the elastic ball 122 has the function of supporting the prosthesis in the vertical direction when it sinks due to occlusion. Therefore, by making the elastic modulus of the elastic ball 122 larger than that of the elastic ring 120, when the elastic ring 120 is significantly deformed due to occlusion pressure, the elastic ball 122 can quickly and strongly push back the prosthesis.

3 and 4, the elastic ring 120 has an elliptical cross-sectional shape. As already described, since the forming direction L3 of the mounting groove 106 is inclined with respect to the axis L2 of the abutment 18, the long axis of the elastic ring 120 (specifically, the long axis of the cross-sectional shape (elliptical) of the elastic ring 120) is also inclined with respect to the axis L2. In this embodiment, the long axis of the elastic ring 120 coincides with the forming direction L3 of the mounting groove 106. The inner diameter of the elastic ring 120 is smaller than the diameter of the mounting groove 106 (the diameter of the bottom of the mounting groove 106). As a result, when the elastic ring 120 is attached to the mounting groove 106, the elasticity of the elastic ring 120 allows the elastic ring 120 to be appropriately held within the mounting groove 106.

As already explained, the cap 110 is embedded in the floor 58, and the inner peripheral surface 114a of the cap 110 forms an engagement hole 59. As shown in Figs. 3 and 4, the cap 110 has a tubular side portion 114 and a bottom portion 112 that closes one end of the side portion 114, and the inner peripheral surface 114a (engagement hole 59) of the cap 110 has a shape following the protruding portion 104 (exposed portion 20) of the abutment 18. The bottom portion 112 (upper end portion in Fig. 3) of the cap 110 faces the upper end surface of the protruding portion 104 of the abutment 18.

A groove 114b with which the elastic ring 120 can engage is formed on the inner circumferential surface 114a of the cap 110 (engagement hole 59). The groove 114b extends in the circumferential direction along the inner circumferential surface 114a of the cap 110, and goes around the protruding portion 104. The groove 114b has a shape that follows the shape of the elastic ring 120. As shown in Figures 3 and 4, the formation direction (extension direction) of the groove 114b is opposite to the formation direction L3 of the mounting groove 106, and extends diagonally. As is clear from Figures 3 and 4, the inner diameter of the inner circumferential surface of the cap 110 above the groove 114b (artificial tooth side) is larger than the inner diameter below the groove 114b (gingival side). That is, the inner circumferential surface 114a located above the groove 114b is offset outward from the inner circumferential surface 114a located below the groove 114b. In addition, the outer diameter of the elastic ring 120 is slightly larger than the diameter of the groove 114b (the diameter of the bottom of the groove 114b). As a result, when the elastic ring 120 engages with the groove 114b, the elasticity of the elastic ring 120 ensures that the elastic ring 120 is held in the groove 114b.

When the above-mentioned protrusion 104 (exposed portion 20) is inserted into the inner peripheral surface 114a of the cap 110 (engagement hole 59) and the two engage with each other, the elastic ring 120 attached to the protrusion 104 engages with the groove 114b of the cap 110. As is clear from FIG. 4, in a state where no external force is applied to the prosthesis 12 (i.e., the cap 110), a clearance is formed between the outer peripheral surface of the protrusion 104 and the inner peripheral surface 114a of the cap 110. In detail, the outer surface of the protrusion 104 does not contact the inner peripheral surface 114a of the cap 110, and a clearance is formed over the entire outer surface of the protrusion 104. Therefore, the protrusion 104 is fixed to the inner peripheral surface 114a of the cap 110 only through the elastic ring 120. In this embodiment, the clearance formed between the outer peripheral surface of the protrusion 104 and the inner peripheral surface 114a of the cap 110 is adjusted to be different depending on the location. Specifically, clearances C3 and C4 (>0) are formed between the outer peripheral side of the truncated cone-shaped protrusion 104 and the inner peripheral surface 114a of the cap 110. As already described, the outer peripheral side of the protrusion 104 located above the mounting groove 106 is offset outward from the outer peripheral side located below the mounting groove 106. Therefore, the clearances C3 and C4 formed between the outer peripheral side of the protrusion 104 and the inner peripheral surface 114a of the cap 110 are smaller above the mounting groove 106 than below the mounting groove 106 (C3<C4). The clearance C3 is set, for example, to be greater than 0 mm and equal to or less than 0.6 mm (i.e., 0<C3≦0.6 mm), and the clearance C4 is set, for example, to be greater than 0 mm and equal to or less than 0.8 mm (i.e., 0<C4≦0.8 mm). In this embodiment, C3 is set to 0.6 mm or less because the physiological movement (i.e., the cushion of the periodontal ligament) when stress such as occlusion force is applied to a natural tooth is about 0.5 mm, so it is set to a value slightly larger than this. Also, C4 is set to 0.8 mm or less because the outer peripheral side surface located above the mounting groove 106 is offset outward from the outer peripheral side surface located below the mounting groove 106, so the offset amount of 0.2 mm is added to C3 (≦0.6 mm).

In addition, a clearance C2 (>0) is formed between the upper end surface of the truncated cone-shaped protrusion 104 and the inner peripheral surface 114a of the cap 110 (more specifically, the bottom 112 of the cap 110). Furthermore, as shown in FIG. 4, a clearance C1 (>0) is formed between the elastic ball 122 attached to the upper end surface of the protrusion 104 and the inner peripheral surface 114a (bottom 112) of the cap 110. Since a part of the elastic ball 122 protrudes from the upper end surface of the protrusion 104, the clearance C1 is smaller than the clearance C2 (C1<C2). The clearance C2 is set, for example, to be greater than 0 mm and equal to or less than 0.6 mm (i.e., 0<C2≦0.6 mm), and the clearance C1 is set, for example, to be greater than 0 mm and equal to or less than 0.3 mm (i.e., 0<C1≦0.3 mm). In this embodiment, C2 is set to 0.6 mm or less because when a vertical bite force is applied to a prosthesis that is in contact with the mucosa with zero bite force, the mucosa is pressed and the prosthesis sinks into the mucosa by about 0.5 mm, so a value slightly larger than this is used. Also, C1 is set to 0.3 mm or less because the elastic ball 122 is spherical, and the repulsive force becomes smaller when the prosthesis begins to contact the elastic ball 122. For this reason, C1 is set to half the value of C2. However, the timing at which the elastic ball 122 begins to support the prosthesis can be set arbitrarily, and C2 may be set to < 0.6 mm, or C2 may be set to < C1/2.

Although no clearance is formed between the bottom surface of the bed 58 and the gums 24, when an external force acts from the prosthesis 12 toward the gums 24, the gums 24 sink (usually the amount of gum sinking is 3 to 5 mm). Therefore, when a downward external force acts on the prosthesis 12, i.e., the cap 110, the cap 110 can move toward the upper end surface of the protrusion 104. A clearance C1 is formed between the elastic ball 122 and the inner peripheral surface 114a (bottom 112) of the cap 110, but the clearance C1 is set smaller than the maximum amount of sinking of the gums 24. Therefore, when the cap 110 moves toward the upper end surface of the protrusion 104, the cap 110 comes into contact with the elastic ball 122 before moving to the maximum amount of sinking of the gums 24.

In the engagement structure between the protrusion 104 and the cap 110 (engagement hole 59) described above, when an external force acts on the prosthesis 12, the elastic ring 120 deforms, and the prosthesis 12 can move relative to the protrusion 104. In particular, since clearances C1, C2, C3, and C4 are formed over the entire outer surface of the protrusion 104, the prosthesis 12 can move in various directions depending on the direction in which the external force acts. Therefore, the external force acting from the prosthesis 12 to the protrusion 104 is dispersed, and it is possible to suppress the application of a large external force locally to the protrusion 104, and it is possible to suppress the reaction of the external force that the prosthesis 12 receives from the protrusion 104. In addition, when the prosthesis 12 moves significantly relative to the protrusion 104, the elastic ball 122 and the cap 110 come into contact with each other, and the external force acting from the prosthesis 12 to the protrusion 104 is further dispersed, and the movement of the prosthesis 12 is restricted. This prevents the cap 110 from coming into direct contact with the protrusion 104, and prevents a large force from acting locally on the prosthesis 12 and the abutment 18. On the other hand, when the external force acting on the prosthesis 12 is removed, the restoring force of the elastic ring 120 and the elastic ball 122 causes the prosthesis 12 to return to its original position (the position when no external force is acting (one example of the initial position) shown in FIG. 4). At this time, the elastic ring 120 is suitably held in the mounting groove 106 of the abutment 18 and in the groove 114b of the cap 110, so that the prosthesis 12 can easily return to its original position and can be suitably restored to the appropriate state.

In the denture system 1 of the first embodiment, an elastic ring 120 and an elastic ball 122 are disposed between the abutment 18 and the prosthesis 12, 14, and a clearance is formed between the abutment 18 and the prosthesis 12, 14. Therefore, when an external force acts on the prosthesis 12, 14, the prosthesis 12, 14 can move in any direction relative to the implant (16, 18). Therefore, it is possible to suppress the application of a large external force locally to the prosthesis 12, 14 and the implant (16, 18), and to suppress damage to the prosthesis 12, 14 and the implant (16, 18). That is, in the denture system 1 of the present embodiment, the elastic ring 120 and the elastic ball 122 function as a periodontal ligament, allowing the prosthesis 12, 14 to move naturally relative to the implant (16, 18), and suppressing the application of an excessive external force to the prosthesis 12, 14 and the implant (16, 18). In particular, in this embodiment, the bases 58, 88 do not contact the alveolar mucosa 25, 29, and the contact area between the bases 58, 88 and the oral cavity surface is reduced. As a result, a relatively large external force (occlusal pressure) acts on the prosthesis 12, 14 and the implant (16, 18), but this external force can be suitably absorbed by the elastic ring 120 and the elastic ball 122. This makes it possible to significantly reduce both the discomfort felt when wearing the prosthesis and the external force acting on the prosthesis 12, 14 and the implant (16, 18).

In the denture system 1 of Example 1, the formation direction L3 of the mounting groove 106 and the formation direction of the groove 114b are inclined with respect to the axis L2, the outer diameter of the outer peripheral surface of the protrusion 104 is offset across the mounting groove 106, and the inner diameter of the inner peripheral surface 114a of the cap 110 is offset across the groove 114b. That is, the engagement structure between the elastic ring 120 and the mounting groove 106 is configured so that the force required to remove the prosthesis 12, 14 from the abutment 18 is large. Furthermore, the cross-sectional shape of the elastic ring 120 is elliptical. As a result, the prosthesis 12, 14 can be easily attached to the abutment 18 with a relatively small force, while the force required to remove the prosthesis 12, 14 from the abutment 18 can be increased. This makes it possible to prevent the prosthesis 12, 14 from being unintentionally detached from the abutment 18. Furthermore, in the denture system 1 of Example 1, the prostheses 12, 14 sink on the side where bite pressure is strong when biting food (the so-called working side (e.g., the right molar)), while the prostheses 12, 14 rise on the opposite side (the so-called non-working side (e.g., the left molar)). In this case, according to the principle of action and reaction, the prostheses 12, 14 on the non-working side tend to rise to the same extent as the prostheses 12, 14 on the working side sink. However, in the denture system 1 of Example 1, the external force required to cause the prostheses 12, 14 to rise is greater than the external force required to cause the prostheses 12, 14 to sink. As a result, the non-working side of the prostheses 12, 14 suppresses the working side of the prostheses 12, 14 from unilaterally sinking. Conversely, when one side of the prostheses 12, 14 (for example, the molar on the right side) tries to rise, the other side of the prostheses 12, 14 tries to sink. At this time, the external force required when the prostheses 12, 14 try to sink is smaller than the external force required when the prostheses 12, 14 try to rise. As a result, when one side of the prostheses 12, 14 tries to rise unilaterally, the other side of the prostheses 12, 14 easily sinks, suppressing excessive lifting of one side of the prostheses 12, 14. Therefore, in the denture system 1 of Example 1, by holding the prostheses 12, 14 with the multiple abutments 18, excessive sinking or excessive lifting of the prostheses 12, 14 from the appropriate position can be suppressed, and the prostheses 12, 14 can be appropriately held. In addition, since the prostheses 12, 14 are held by a plurality of abutments 18, the external force acting on the prostheses 12, 14 is dispersed, and it is possible to prevent an excessive external force from acting on a specific abutment 18. As described above, in the denture system 1 of the first embodiment, when an external force acts on the prostheses 12, 14, the movement can be appropriately controlled (i.e., excessive movement can be prevented), and as a result, food can be chewed well, while the external force acting on the implants (16, 18) and the load acting on the prostheses (12, 14) can be kept low. Furthermore, the strength of the movement of the prostheses 12, 14 can be easily adjusted by adjusting the material of the elastic ring 120 and the elastic ball 122, the angle of the mounting groove 106, the protruding amount of the elastic ring 120 and the elastic ball 122 (i.e., the protruding amount from the outer circumferential surface of the protruding portion 104), and the like. For example, by increasing the amount of protrusion of the elastic ring 120, the range of movement of the prostheses 12, 14 can be increased, and the load acting on the prostheses 12, 14 can be reduced. Conversely, by decreasing the amount of protrusion of the elastic ring 120, the adjustment range of the prostheses 12, 14 can be reduced, and the stability of the prostheses 12, 14 can be improved.

Note that while the denture system 1 of Example 1 described above is a denture system for an edentulous jaw, the technology disclosed in this specification is not limited to such a form. There is no limit to the number of artificial teeth provided in the prosthesis, and it may be one, or any number of two or more.

In addition, in the denture system 1 of the above-mentioned Example 1, the formation direction L3 of the mounting groove 106 and the formation direction of the groove 114b are inclined with respect to the axis L2 of the protrusion 104, but the technology disclosed in this specification is not limited to such a form. For example, the formation direction L3 of the mounting groove 106 and the formation direction of the groove 114b may be perpendicular to the axis L2 of the protrusion 104. In addition, the outer diameter of the outer peripheral surface of the protrusion 104 may not be offset across the mounting groove 106, and the inner diameter of the inner peripheral surface of the cap 110 may not be offset across the groove 114b. Furthermore, the cross-sectional shape of the elastic ring 120 may also be circular. Even in such a form, the prosthesis 12, 14 can be attached and detached to the abutment 18 in an appropriate manner by appropriately selecting the material of the elastic ring 120. In addition, by appropriately adjusting the inclination angle of the mounting groove 106 relative to the axis L2 and the offset amount of the outer diameter of the outer peripheral surface of the protrusion 104, the force required to remove the prosthesis 12, 14 from the abutment 18 can be made greater than the force required to attach the prosthesis 12, 14 to the abutment 18, and the retention force of the prosthesis 12, 14 can be adjusted to the desired magnitude.

In addition, the denture system 1 of the above-mentioned Example 1 required two members, the elastic ring 120 and the elastic ball 122, but the technology disclosed in this specification is not limited to such a form. For example, as shown in Figures 5 and 6, an elastic member 220 in which an elastic ring portion 222 (another example of the "first elastic portion") and an elastic ball portion 224 (another example of the "second elastic portion") are integrated may be used. As shown in Figures 5 and 6, an attachment groove 206 is formed on the side of the protruding portion 204 of the abutment 18a, and a recess 208 is formed on the upper end surface of the protruding portion 204. In addition, a fitting portion 226 extending downward from the elastic ball portion 224 is formed in the elastic member 220. The elastic ring portion 222 of the elastic member 220 is attached to the attachment groove 206, and the fitting portion 226 of the elastic member 220 is fitted into the recess 208, so that the elastic member 220 can be firmly attached to the abutment 18a. The elastic ring portion 222 engages with the groove 214b of the cap 210 in the same manner as in the first embodiment. In this embodiment, the elastic member 220 is formed by integrating the elastic ring portion 222 and the elastic ball portion 224, and the abutment 18a of the elastic member 220 can be easily attached.

In addition, in the denture system 1 of Example 1 described above, the elastic ring 120 and the elastic ball 122 are attached to the abutment 18, and a groove 114b into which the elastic ring 120 engages is formed in the cap 110, but the technology disclosed in this specification is not limited to this form. For example, the elastic ring 120 and the elastic ball 122 may be attached to the cap, and a groove into which the elastic ring 120 engages may be formed in the abutment. This form also allows the prosthesis to move relative to the implant, and external forces acting on the prosthesis and implant can be reduced.

In addition, in the denture system 1 of Example 1 described above, the elastic ring 120 and the elastic ball 122 are detachably attached to the abutment 18, but the technology disclosed in this specification is not limited to this form. For example, the elastic ring 120 and the elastic ball 122 may be attached to the abutment 18 in an undetachable manner. In this case, there is no need to form an attachment groove and a recess in the abutment 18, and the elastic ring and the elastic ball may be fixed directly to the outer circumferential surface of the abutment. Similarly, when the elastic ring and the elastic ball are provided on the engagement hole side of the prosthesis, the elastic ring may be attached to the engagement hole in a detachable or undetachable manner.

Although the above-mentioned examples relate to denture systems in which fixtures are embedded in the alveolar bone, the technology disclosed in this specification can also be applied to cases in which natural tooth roots are used. In other words, it can also be applied to denture systems in which abutments are fixed to natural tooth roots and prostheses are held on these abutments.

Although the embodiments of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of those objectives is itself technically useful.

16 Fixture 18 Abutment 104 Protrusion 106 Mounting groove 108 Recess 110 Cap 112 Bottom 114 Side surface 114a Inner circumferential surface 114b Groove 120 Elastic ring 122 Elastic ball

Claims (9)

A denture system comprising an implant and a prosthesis attached to the implant,
The implant comprises:
A fixture portion to be embedded in the alveolar bone;
and an abutment portion fixed to the fixture portion and having an exposed portion exposed from the gums covering the alveolar bone,
The prosthesis is provided with an engagement hole with which the exposed portion engages,
an elastic body is disposed between an outer circumferential surface of the exposed portion and an inner circumferential surface of the engagement hole;
The elastic body is
a first elastic portion that is disposed at a height between a base end that is an end of the exposed portion on the fixture portion side and a tip end that is an end of the exposed portion on the opposite side to the fixture portion when the exposed portion is engaged with the engagement hole;
a second elastic portion disposed between the tip end of the exposed portion and a bottom portion of the engagement hole when the exposed portion is engaged with the engagement hole ,
When the exposed portion is inserted into the engagement hole, the first elastic portion contacts the exposed portion and an inner circumferential surface of the engagement hole, and the exposed portion is engaged with the engagement hole by the first elastic portion, so that the prosthesis is attached to the abutment portion,
In a first state in which the prosthesis is attached to the abutment portion and no external force is acting on the prosthesis,
a first clearance is provided between an entire surface of the second elastic portion and a bottom of the engagement hole;
the elastic body is not disposed between the base end of the exposed portion and a height at which the first elastic portion is disposed, and a second clearance is provided between the exposed portion and an inner circumferential surface of the engagement hole ,
A denture system , wherein a third clearance is provided between the exposed portion or the elastic body and the inner surface of the engagement hole between the first elastic portion and the second elastic portion . the elastic body further includes a third elastic portion that connects and integrates the first elastic portion and the second elastic portion,
The third elastic portion is disposed between the first elastic portion and the second elastic portion,
The denture system according to claim 1 , wherein the third clearance is provided between the third elastic portion and an inner peripheral surface of the engagement hole . The elastic body is formed of a material different from that of the abutment portion,
The denture system according to claim 1 or 2, wherein the elastic modulus of the elastic body is smaller than the elastic modulus of the abutment portion. the first elastic portion is attached to one of an outer circumferential surface of the exposed portion and an inner circumferential surface of the engagement hole,
a groove into which the first elastic portion can be engaged is provided on the other of the outer circumferential surface of the exposed portion and the inner circumferential surface of the engagement hole,
The denture system according to claim 3, wherein the exposed portion is inserted into the engagement hole and the first elastic portion is engaged with the groove, so that the exposed portion engages with the engagement hole and the prosthesis is attached to the abutment portion. The denture system according to claim 4, wherein the first elastic part has a ring shape that extends in the circumferential direction along the outer peripheral surface of the exposed part and goes around the periphery of the exposed part, and is removably attached to the outer peripheral surface of the exposed part. The prosthesis is adapted to be removably attached to the abutment portion,
The denture system according to claim 5, wherein the engagement structure between the first elastic portion and the groove is configured so that the force required to remove the prosthesis from the abutment portion is greater than the force required to attach the prosthesis to the abutment portion . A recess is formed in the tip of the exposed portion,
The denture system according to any one of claims 1 to 6, wherein the second elastic portion is attached to the tip end of the exposed portion by engaging a portion of the second elastic portion within the recess. An implant to which a prosthesis is attached,
A fixture portion to be embedded in the alveolar bone;
an abutment part fixed to the fixture part and having an exposed part exposed from the gums covering the alveolar bone;
an elastic body attached to an outer peripheral surface of the exposed portion,
The prosthesis is provided with an engagement hole with which the exposed portion can be engaged,
the elastic body is disposed between an outer circumferential surface of the exposed portion and an inner circumferential surface of the engagement hole,
The elastic body is
a first elastic portion that is disposed at a height between a base end that is an end of the exposed portion on the fixture portion side and a tip end that is an end of the exposed portion on the opposite side to the fixture portion when the exposed portion is engaged with the engagement hole;
a second elastic portion disposed between the tip end of the exposed portion and a bottom portion of the engagement hole when the exposed portion is engaged with the engagement hole,
When the exposed portion is inserted into the engagement hole, the first elastic portion contacts the exposed portion and an inner circumferential surface of the engagement hole, and the exposed portion is engaged with the engagement hole by the first elastic portion, so that the prosthesis is attached to the abutment portion,
In a first state in which the prosthesis is attached to the abutment portion and no external force is acting on the prosthesis,
a first clearance is provided between an entire surface of the second elastic portion and a bottom of the engagement hole;
the elastic body is not disposed between the base end of the exposed portion and a height at which the first elastic portion is disposed, and a second clearance is provided between the exposed portion and an inner circumferential surface of the engagement hole ,
The implant , wherein a third clearance is provided between the exposed portion or the elastic body and an inner circumferential surface of the engagement hole between the first elastic portion and the second elastic portion . an abutment attached to a natural tooth root and having an exposed portion exposed from the gums covering the alveolar bone;
a prosthesis attached to the abutment;
The prosthesis is provided with an engagement hole with which the exposed portion can be engaged,
an elastic body is disposed between an outer circumferential surface of the exposed portion and an inner circumferential surface of the engagement hole;
The elastic body is
a first elastic portion that is disposed at a height between a base end portion, which is an end portion on the natural tooth root side of the exposed portion, and a tip end portion, which is an end portion on the opposite side to the natural tooth root, of the exposed portion when the exposed portion is engaged with the engagement hole;
a second elastic portion disposed between the tip end of the exposed portion and a bottom portion of the engagement hole when the exposed portion is engaged with the engagement hole,
When the exposed portion is inserted into the engagement hole, the first elastic portion contacts the exposed portion and an inner circumferential surface of the engagement hole, and the exposed portion is engaged with the engagement hole by the first elastic portion, so that the prosthesis is attached to the abutment portion,
In a first state in which the prosthesis is attached to the abutment portion and no external force is acting on the prosthesis,
a first clearance is provided between an entire surface of the second elastic portion and a bottom of the engagement hole;
the elastic body is not disposed between the base end of the exposed portion and a height at which the first elastic portion is disposed, and a second clearance is provided between the exposed portion and an inner circumferential surface of the engagement hole ,
A denture system , wherein a third clearance is provided between the exposed portion or the elastic body and the inner surface of the engagement hole between the first elastic portion and the second elastic portion .

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