Dental abutment, dental prosthesis, connection structure between dental abutment and dental prosthesis, and dental implant

Abstract

To easily and appropriately position a dental prosthesis and an abutment, and to appropriately prevent misalignment of the dental prosthesis with the abutment.SOLUTION: A dental abutment 20 includes: a base 21 fixed to an implant fixture 10 embedded in an alveolar bone 1; and an embedding part 22 fixed to an embedding hole 33 provided in a dental prosthesis 30. The implanting portion 22 includes a first flat surface 23a, a second flat surface 23b, and a spring member 24. The first flat surface 23a, the second flat surface 23b corresponding to the first flat surface 35a and the second flat surface 35b are provided in the embedding hole 33. When the embedded portion 22 is inserted into the embedding hole 33, the spring member 24 biases an embedded portion 23 in a direction in which the first flat surface 23a and the second flat surface 23b are pressed against the first flat surface 35a and the second flat surface 35b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a dental abutment, a dental prosthesis, a connecting structure between a dental abutment and a dental prosthesis, and a dental implant. [Background technology]

[0002] BACKGROUND ART There is known a technique relating to a dental implant in which a dental prosthesis such as a crown is fixed to an implant fixture embedded in the alveolar bone via a dental abutment (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a technology in which, when the embedding portion of an abutment is inserted into the embedding hole of a dental prosthesis, a first flat surface formed on the inner surface of the embedding hole and a second flat surface formed on the outer periphery of the embedding portion are aligned in correspondence with each other, and a protrusion formed on the embedding hole is cut, thereby positioning the dental prosthesis and the abutment, and firmly connecting and fixing the abutment and dental prosthesis to prevent misalignment such as rotation.

[0004] Patent Document 2 discloses a technology in which the embedding portion of an abutment that is embedded in an embedding hole of a dental prosthesis has an expansion portion made up of multiple thin plates or the like extending in the axial direction, and when the embedding portion is inserted into the embedding hole and fixed to a fixture with a screw part, a lateral force is applied to the expansion portion by the screw part, causing the outer diameter of the expansion portion to elastically increase, fixing the dental prosthesis to the abutment and preventing the dental prosthesis from moving.

[0005] However, in the conventional technology described in Patent Document 1, the protrusions are cut when the dental prosthesis and the abutment are fixed, which means that redoing is not possible and requires high skill from dental technicians, etc. Furthermore, because the protrusions cannot be repaired, the dental prosthesis may have to be remade in cases such as when excessive cutting is required. Furthermore, in the conventional technology described in Patent Document 2, the abutment and dental prosthesis are not fixed until the screw part is attached, which means there is a possibility of unexpected misalignment during the attachment work to the fixture. Furthermore, because the structure of the extension part is complex and there are many parts, the manufacturing and assembly of the abutment is cumbersome. Furthermore, the inner surface of the dental prosthesis must be machined to a complex shape to accommodate the complex shape of the extension part, which makes the processing of the dental prosthesis also cumbersome. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2017 / 169037 [Patent Document 2] Special Publication No. 2019-529047 Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure has been made in light of the above-mentioned problems, and aims to enable the positioning of an abutment and a dental prosthesis to be performed simply and appropriately, and to appropriately prevent the dental prosthesis from shifting position relative to the abutment. [Means for solving the problem]

[0008] To achieve the above object, the dental abutment of the present disclosure is a dental abutment having a base portion fixed to an implant fixture that is implanted into alveolar bone, and an embedding portion fixed to an embedding hole provided in a dental prosthesis. The embedding portion has at least one flat surface provided on its outer periphery and a spring member, and an abutment surface corresponding to the flat surface is provided in the embedding hole, and the spring member biases the embedding portion in a direction in which the flat surface is pressed against the abutment surface when the embedding portion is inserted into the embedding hole. The dental prosthesis of the present disclosure is a dental prosthesis fixed to an implant fixture implanted into alveolar bone via a dental abutment. The dental abutment includes an implantation portion having at least one flat surface on its outer periphery and a spring member and fixed to the dental prosthesis. The dental prosthesis includes an implantation hole having an abutment surface corresponding to the flat surface and into which the implantation portion is inserted. The spring member biases the implantation portion in a direction in which the flat surface is pressed against the abutment surface when the implantation portion is inserted into the implantation hole. The present disclosure also provides a connection structure for a dental abutment and a dental prosthesis for use in a dental implant, wherein the dental abutment includes an embedding portion having at least one flat surface on its outer periphery and a spring member and fixed to the dental prosthesis, the dental prosthesis including an embedding hole having an abutment surface corresponding to the flat surface and into which the embedding portion is inserted, and the spring member biases the embedding portion in a direction in which the flat surface is pressed against the abutment surface when the embedding portion is inserted into the embedding hole. The dental implant of the present disclosure is a dental implant comprising an implant fixture, a dental abutment, and a dental prosthesis, wherein the dental abutment comprises a base portion fixed to the implant fixture and an embedding portion fixed to the dental prosthesis, the embedding portion having at least one flat surface on its outer periphery and a spring member, the dental prosthesis having an abutment surface corresponding to the flat surface and an embedding hole into which the embedding portion is inserted, the spring member biasing the embedding portion in a direction in which the flat surface is pressed against the abutment surface when the embedding portion is inserted into the embedding hole. [Effects of the Invention]

[0009] With this configuration, the implantation portion is guided in the rotational direction relative to the implantation hole in a direction in which the flat surface abuts against the abutment surface, and the flat surface abuts against the abutment surface while being pressed against the abutment surface. This allows the abutment and the dental prosthesis to be properly positioned and prevents their relative movement in the rotational direction. Therefore, the abutment and the dental prosthesis can be easily and properly positioned, and displacement of the dental prosthesis relative to the abutment can be properly prevented. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded view of a dental implant according to a first embodiment. [Figure 2] FIG. 1 is a cross-sectional view showing a state in which the dental implant according to the first embodiment is used. [Figure 3] 1A and 1B are a side view, a front view, a perspective view, and a plan view of an abutment according to a first embodiment. [Figure 4] 1A and 1B are explanatory diagrams for explaining the configuration of the dental prosthesis relating to the first embodiment, in which (a) is a front view of the dental prosthesis for anterior teeth to which an abutment is fixed, and (b) is a bottom view of the dental prosthesis for anterior teeth. [Figure 5]1A and 1B are explanatory diagrams for explaining a preferred configuration of the first and second flat surfaces and the spring member, where FIG. 1A shows a preferred positional relationship between the first and second flat surfaces and the spring member, and FIG. 1B shows a positional relationship between the first and second flat surfaces and the spring member when the thickness of the first and second flat surfaces is minimized. [Figure 6] FIG. 10 is a perspective view of an abutment of a first modified example. [Figure 7] FIG. 10 is a perspective view of an abutment of a second modified example. [Figure 8] FIG. 11 is a perspective view of an abutment of a modified example 3. [Figure 9] 10A and 10B are a side view and a rear view of an abutment of Modified Example 4. FIG. [Figure 10] FIG. 13 is a plan view of an abutment of a fifth modified example. [Figure 11] FIG. 13 is a plan view of an abutment of a sixth modified example. [Figure 12] FIG. 13 is a plan view of an abutment of a seventh modified example. [Figure 13] FIG. 13 is a plan view of an abutment of Modified Example 8. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Hereinafter, a dental abutment, a dental prosthesis, and a dental implant according to a first embodiment will be described with reference to the drawings.

[0012] First, the configuration of a dental implant 100 according to the first embodiment will be described with reference to the exploded view of Fig. 1 and the cross-sectional view of Fig. 2. As shown in Figs. 1 and 2, the dental implant 100 mainly includes an implant fixture 10 (hereinafter simply referred to as "fixture 10"), a dental abutment 20 (hereinafter simply referred to as "abutment 20"), a dental prosthesis 30, and a screw 40.

[0013] The fixture 10 is embedded in an implant cavity 2 formed in the alveolar bone 1 (see FIG. 2) of a patient's jawbone. The fixture 10 is a screw-type fixture having an axial main body 11 and a screw portion 12 provided on the outer periphery of the main body 11. The main body 11 is configured so that one end (rear end) that is inserted into the implant cavity 2 is closed and the other end (front end) where the abutment 20 is attached is open, and is provided with a fitting hole 13 into which a base 21 (described later) of the abutment 20 is fitted and fixed, and a screw hole (female thread) 14 into which a male thread portion 41 of a screw 40 is screwed.

[0014] The fixture 10 having such a configuration is fixed to the alveolar bone 1 by being screwed into an implant socket 2 formed in a tooth-missing portion of the alveolar bone 1. However, the fixture 10 is not limited to this configuration, and it may also be a cylindrical fixture that does not have a screw portion 12 and is fixed to the alveolar bone 1 by being fitted into the implant socket 2.

[0015] Suitable materials for the fixture 10 include, but are not limited to, metals such as titanium and titanium alloys, and ceramics such as alumina and zirconia. In this embodiment, the fixture 10 is made of a titanium alloy.

[0016] Hereinafter, in this specification, for the implant 100 and each of its constituent parts (fixture 10, abutment 20, dental prosthesis 30), the direction along the axis of the implant 100 will be referred to as the axial direction, the side inserted into the alveolar bone 1 will be referred to as the posterior end or root end, and the opposite side (the direction toward the dental prosthesis 30) will be referred to as the distal end. Furthermore, for the tooth or dental prosthesis 30, the surface that is positioned in the lingual direction will be referred to as the lingual surface, and the surface that is positioned in the opposite direction to the lingual direction, that is, toward the lips and cheeks (hereinafter referred to as the "labio-buccal direction") will be referred to as the labio-buccal surface.

[0017] Next, the configuration of the abutment 20 will be described with reference to Fig. 3. The abutment 20 has a base 21 and an embedding portion 22. The base 21 has a screw insertion hole 21a, is made of a tubular member with a rectangular cross section along its axis, and is fitted into the fitting hole 13 of the fixture 10. The screw insertion hole 21a is a hole through which the male thread portion 41 of the screw 40 is inserted, and has an inner diameter that is approximately the same as the outer diameter (maximum outer diameter) of the male thread portion 41.

[0018] The embedding portion 22 has a screw accommodating hole 22a, is larger in diameter than the base portion 21, and is made of a tubular member having a rectangular or trapezoidal cross section along its axis. The embedding portion 22 is inserted into an embedding hole 33 of the dental prosthesis 30 (described later) and fixed with a dental adhesive such as cement. The inner diameter of the screw accommodating hole 22a is larger than the inner diameter of the screw insertion hole 21a and is large enough to accommodate the head 42 of the screw 40. An engagement portion 22b is provided between the base portion 21 and the embedding portion 22 (between the screw insertion hole 21a and the screw accommodating hole 22a) to engage with the head 42 of the screw 40 placed in the screw accommodating hole 22a.

[0019] The embedding portion 22 is provided with two flat surfaces 23 on its outer periphery, i.e., a first flat surface 23a and a second flat surface 23b, and a spring member 24. Hereinafter, when the first flat surface 23a and the second flat surface 23b are not distinguished from each other, they will be simply referred to as the flat surface 23. The first flat surface 23a and the second flat surface 23b are formed by cutting out a portion of the cylindrical outer periphery of the embedding portion 22 in a substantially rectangular shape along the axis of the embedding portion 22, and are recessed inward (inner diameter direction, from the outside toward the center). The first flat surface 23a and the second flat surface 23b can be formed, for example, by cutting the outer periphery of the embedding portion 22 along the axis, a so-called D-cut. However, the present invention is not limited to this, and the first flat surface 23a and the second flat surface 23b may be formed using a formwork or the like having flat surfaces corresponding to the first flat surface 23a and the second flat surface 23b.

[0020] In addition, the flat surface 23 is not limited to such a notched shape, and as another different shape, the flat surface 23 may be a shape in which a part of the outer surface of the embedded portion 22 protrudes outward (in the outer diameter direction, in the direction from the center to the outside), as long as a flat surface is formed relative to the outer surface consisting of the curved surface of the main body portion of the embedded portion 22.

[0021] The circumferential length (width) of the first flat surface 23a and the second flat surface 23b is preferably 1 mm or more. The thickness of the first flat surface 23a and the second flat surface 23b is preferably 0.4 mm or more. By setting these dimensions, the abutment 20 and the dental prosthesis 30 can be appropriately positioned by the first flat surface 23a and the second flat surface 23b, and the strength of the abutment 20 can be appropriately maintained. The dimensions of the first flat surface 23a and the second flat surface 23b are not limited to the above dimensions and can be changed as appropriate depending on the size, material, etc. of the abutment 20.

[0022] The spring member 24 is composed of a leaf spring that is arranged along the axial direction of the implantation portion 22 and is movable in the outer and inner diameter directions of the implantation portion 22, and urges the implantation portion 22 in a direction pressing it against the inner surface of the implantation hole 33. In this embodiment, the spring member 24 is a cantilevered leaf spring formed by cutting out a rectangular portion of the wall of the implantation portion 22. The rear end of the spring member 24 is a fixed end that is not cut off and is connected to the main body of the implantation portion 22, and is bent outward (in the outer diameter direction) around a valley fold near this fixed end, so that the tip side becomes a free end that is movable in the outer and inner diameter directions. The spring member 24 is formed by cutting out the wall of the embedded portion 22 slightly rearward of the tip, and the tip side of the wall of the embedded portion 22 has a structure without a notch, but the spring member 24 may also be formed by cutting out the wall of the embedded portion 22 up to the tip side, and can be selected appropriately depending on the ease of manufacturing, the material, etc.

[0023] Furthermore, an opening formed in the embedding portion 22 by cutting out the spring member 24 serves as a housing portion 25 capable of housing the spring member 24. Furthermore, the embedding portion 22 is provided with an annular flange portion 26 that protrudes outward (in the outer radial direction) at its rear end side (toward the base portion 21). The rear end of the dental prosthesis 30 is positioned on this flange portion 26, which functions as a support portion and a stopper that supports the dental prosthesis 30. Furthermore, the rear end of the embedding portion 22 serves as an abutment portion 27 that abuts against the tip of the fixture 10.

[0024] Suitable materials for the abutment 20 include, but are not limited to, metals such as titanium, titanium alloys, and stainless steel, ceramics such as alumina and zirconia, and resins such as PEEK (polyether ether ketone).The spring member 24 is preferably made of an elastically deformable material with a Young's modulus of 200 GPa or less, and more preferably made of an elastically deformable material with a Young's modulus of 100 to 120 GPa.

[0025] The abutment 20 of this embodiment is formed, for example, from titanium with a Young's modulus of 106 GPa or a titanium alloy with a Young's modulus of 113 GPa. By being formed from such a material, the abutment 20 has excellent strength, durability, and biocompatibility and can be prevented from deterioration such as rusting. Furthermore, the spring member 24 has excellent shape memory properties and can maintain an appropriate biasing force through elastic deformation.

[0026] Next, a preferred configuration of the flat surface 23 and the spring member 24 will be described with reference to Fig. 5, but the configuration is not limited to that shown in Fig. 5. The flat surface 23 and the spring member 24 are preferably disposed opposite each other across the central axis I of the abutment 20. This configuration allows the spring member 24 to appropriately and efficiently bias the flat surface 23 in a direction pressing it against the abutment surface 35.

[0027] Furthermore, as in this embodiment, the flat surface 23 is preferably configured from two (a pair of) flat surfaces 23, i.e., a first flat surface 23a and a second flat surface 23b, provided by cutting out a rectangular shape from the outer periphery of the embedding portion 22 along the axis of the embedding portion 22. With this configuration, the abutment 20 is guided in the clockwise and counterclockwise directions relative to the dental prosthesis 30 so that the first flat surface 23a and the second flat surface 23b abut against the first abutment surface 35a and the second abutment surface 35b of the embedding hole 33, which will be described later, and the abutment 20 and the dental prosthesis 30 are more appropriately positioned.

[0028] Furthermore, when the distance between the two end points A and C of one axial side (the side toward the tip) of the first flat surface 23a and the two end points B and D of one axial side (the side toward the tip) of the second flat surface 23b is defined as α, and the distance between the end points A and B (line segment AB) on the side closer to the spring member 24 is defined as β, and the distance between the end points C and D (line segment CD) on the side farther from the spring member 24 is defined as β, it is preferable that the following formula (1) is satisfied.

[0029] α>β (1)

[0030] Furthermore, the spring member 24 is preferably disposed on the bisector E of the line segment CD connecting the end points C and D, facing the first flat surface 23a and the second flat surface 23b across the central axis I. In other words, the first flat surface 23a and the second flat surface 23b are preferably provided symmetrically across a plane including the central axis I of the implantation portion 22 and the center J of the spring member 24 in the circumferential direction.

[0031] With the above-described positional relationship, when the embedding portion 22 is inserted into the embedding hole, the spring member 24 applies a substantially uniform biasing force to the first flat surface 23a and the second flat surface 23b in a direction pressing them against the embedding hole 33. This biasing force and the first flat surface 23a and the second flat surface 23b, which are provided symmetrically, guide the dental prosthesis 30 while rotating in either the clockwise or counterclockwise direction, so that the first flat surface 23a and the second flat surface 23b are positioned to abut against the first abutment surface 35a and the second abutment surface 35b, respectively, i.e., so that the dental prosthesis 30 is positioned in an optimal position (best position). As a result, the first flat surface 23a and the second flat surface 23b are respectively positioned in contact with and pressed against the first abutment surface 35a and the second abutment surface 35b, thereby more appropriately positioning the abutment 20 and the dental prosthesis 30 and more appropriately preventing misalignment in the rotational direction.

[0032] Furthermore, while satisfying the above conditions, the first flat surface 23a and the second flat surface 23b preferably have a thickness of 0.4 mm or more, as shown in Fig. 5(b). By setting the thickness to such a value, the portion where the first flat surface 23a and the second flat surface 23b are provided, and further the entire abutment 20, will have a strength that makes them less susceptible to deformation or breakage due to external forces, etc.

[0033] The dental prosthesis 30 has a prosthesis body 31 formed by processing a ceramic material, a zirconia material, a metal material such as titanium, or the like into the shape of a tooth. As shown in Figures 1 and 2, the prosthesis body 31 has a through-hole 32 and an embedding hole 33.

[0034] The through-hole 32 is a cylindrical hole provided through the prosthesis main body 31, and a screw 40 is inserted into the through-hole 32 to be threaded into the screw hole 14 provided in the main body 11 of the fixture 10. The through-hole 32 has an inner diameter that allows the head 42 of the screw 40 to be inserted therethrough.

[0035] The embedding hole 33 is a cylindrical hole provided on the rear end side of the through hole 32, into which the embedding portion 22 of the abutment 20 is embedded. The inner diameter of the embedding hole 33 is formed larger than the inner diameter of the through hole 32, and a step 34 is provided between the embedding hole 33 and the through hole 32, against which the tip of the embedding portion 22 abuts. This step 34 prevents the embedding portion 22 from being inserted excessively into the embedding hole 33.

[0036] The embedding hole 33 is a surface that comes into contact with the flat surface 23 of the abutment 20, and is provided with an abutment surface 35 formed in a flat shape corresponding to the flat surface 23. In this embodiment, the embedding hole 33 is provided with two abutment surfaces, a first abutment surface 35a and a second abutment surface 35b, corresponding to the first flat surface 23a and the second flat surface 23b.

[0037] Furthermore, the inner surface shape of the embedding hole 33, including the portion other than where the first contact surface 35a and the second contact surface 35b are provided, is formed to correspond to the outer surface shape of the embedding portion 22. That is, the embedding hole 33 is formed to have a shape and dimensions that allow the embedding portion 22, with the spring member 24 housed in the housing portion 25, to be accommodated, and the first flat surface 23a and the second flat surface 23b to come into contact with the first contact surface 35a and the second contact surface 35b.

[0038] The inner shape of the embedding hole 33 does not have to be formed to a size that strictly corresponds to the outer shape of the embedding portion 22. Even if there are some manufacturing tolerances in the shapes and dimensions of the embedding hole 33 and the embedding portion 22, the spring member 24 moves in the outer diameter direction within the embedding hole 33, so that the outer diameter of the embedding portion 22 essentially expands, and the spring member 24 presses the main body portion of the embedding portion 22 against the inner surface of the embedding hole 33. This fixes (temporarily fastens) the dental prosthesis 30 and the abutment 20, making it possible to suppress relative rotation, wobbling, etc. between the dental prosthesis 30 and the abutment 20 and absorb the manufacturing tolerances.

[0039] The procedures for fabricating the dental implant 100 configured as described above and the implant treatment procedure will be described below. First, when fabricating the dental prosthesis 30, a dentist or other professional takes an impression of the patient's teeth with the fixture 10 embedded in the alveolar bone 1. In the case of the analog impression method, the dentist takes a mold using an impression material and fabricates a plaster model. Next, the fabricator performs a 3D scan of the plaster model using a 3D measurement device and creates a digital model on a computer based on the scan results. On the other hand, in the case of the digital impression method, the dentist or other professional scans the patient's oral cavity using an intraoral scanner or the like and fabricates a digital model.

[0040] Next, the fabricator uses a digital model created by analog impression method or digital impression method to design the outer and inner surface shapes of the dental prosthesis 30 using dental CAD software. The abutment 20 that fixes this dental prosthesis 30 has a first flat surface 23a, a second flat surface 23b, and a spring member 24. Therefore, by installing data or a design program for the inner surface shape of the embedding hole 33 in advance in the dental CAD software, the fabricator or system manager can generate design data for the inner surface shape provided with the embedding hole 33 having the first abutment surface 35a and the second abutment surface 35b in the dental CAD software.

[0041] The fabricator then loads the design data into CAM software, generates NC data by calculation, mounts a ceramic block, for example, on a cutting machine, and cuts the ceramic block using a cutting tool under computer control, thereby fabricating the dental prosthesis 30 of the first embodiment, which includes the embedding hole 33 having the first contact surface 35a and the second contact surface 35b.

[0042] Teeth have a labio-buccal surface facing the labio-buccal direction and a lingual surface facing the lingual direction, and the dental prosthesis 30 also has a labio-buccal surface and a lingual surface. In consideration of this, for example, the dental prosthesis 30 preferably has an abutment surface 35 on the inner surface of the side that will become the labio-buccal surface. With this configuration, when the abutment 20 to which the dental prosthesis 30 is fixed is secured to the fixture 10, the abutment surface 35 and the flat surface 23 are positioned on the labio-buccal side and facing the labio-buccal direction. This allows the biasing force of the spring member 24 to be distributed across the labio-buccal surfaces of the dental prosthesis 30, thereby reducing the load on the dental prosthesis 30. Furthermore, the abutment between the abutment surface 35 and the flat surface 23 can appropriately prevent rotation of the dental prosthesis 30 during use. The orientation of the flat surface 23 and the abutment surface 35 is not limited to that of the first embodiment and may be positioned in any direction depending on the treatment procedure and ease of operation.

[0043] 1 and 2 show a dental prosthesis 30 for back teeth (molar teeth), which has an abutment surface 35 (see FIG. 1) on the side of the dental prosthesis 30 that will become the labio-buccal surface. In contrast, FIG. 4 shows a dental prosthesis 30 for front teeth (incisors). FIG. 4(a) shows the dental prosthesis 30 for front teeth to which an abutment 20 is fixed. The dental prosthesis 30 has a first abutment surface 35a and a second abutment surface 35b on the side that will become the labio-buccal surface of the dental prosthesis 30, and the first flat surface 23a and the second flat surface 23b of the abutment 20 abut against these, respectively. FIG. 4(b) is a bottom view of the dental prosthesis 30 for front teeth, which has an insertion hole 33 that has a first abutment surface 35a and a second abutment surface 35b on the labio-buccal surface side and is formed with an inner surface shape that corresponds to the outer surface shape of the insertion portion 22.

[0044] Implant treatment for the missing tooth is performed by fixing the abutment 20 and dental prosthesis 30 prepared as described above to the fixture 10 fitted into the patient's alveolar bone 1. To do this, first, a dentist or the like applies a dental adhesive such as cement to the outer surface of the embedding portion 22 of the abutment 20 and the inner surface of the embedding hole 33 of the dental prosthesis 30, inserts the embedding portion 22 into the embedding hole 33, and adhesively fixes the dental prosthesis 30 to the abutment 20.

[0045] However, in the conventional technology, there were problems such as the fact that when the implantation part was inserted into the implantation hole, the protrusion was cut off and could not be undone, and the abutment and dental prosthesis were not fixed until the screw part for fixing to the fixture was attached.

[0046] In contrast, in the dental implant 100 of the first embodiment, the embedding portion 22 of the abutment 20 has a first flat surface 23a and a second flat surface 23b provided on the outer periphery, and a spring member 24. Meanwhile, the dental prosthesis 30 has an embedding hole 33 provided with a first abutment surface 35a and a second abutment surface 35b corresponding to the first flat surface 23a and the second flat surface 23b. With this configuration, the first embodiment can solve the above problem.

[0047] When adhesively fixing the abutment 20 of the first embodiment to the dental prosthesis 30, a dentist or the like pushes the spring member 24 in the inner diameter direction to store the spring member 24 in the storage portion 25. When the embedding portion 22 is inserted into the embedding hole 33 in this state, the spring member 24 restores its original shape and moves in the outer diameter direction, biasing the embedding portion 22. As a result, the embedding portion 22 is guided in the circumferential direction (rotational direction) to a direction (best position) in which the first flat surface 23a and the second flat surface 23b abut against the first abutment surface 35a and the second abutment surface 35b, and the first flat surface 23a and the second flat surface 23b can be quickly and accurately abutted against the first abutment surface 35a and the second abutment surface 35b without the dentist or the like having to manually and precisely align the positions.

[0048] Furthermore, even if there are manufacturing tolerances in the embedding portion 22 and the embedding hole 33, the spring force of the spring member 24 within the embedding hole 33 presses the spring member 24 and the embedding portion 22 firmly against the inner surface of the embedding hole 33, thereby suppressing relative rotation or wobbling between the abutment 20 and the dental prosthesis 30.

[0049] Furthermore, since the abutment 20 and the dental prosthesis 30 can be positioned and fixed by the biasing force of the spring member 24, a dental technician or the like can temporarily connect (temporarily fasten) the abutment 20 and the dental prosthesis 30 and check the connection state, for example, before applying an adhesive. Furthermore, the abutment 20 and the dental prosthesis 30 can be easily attached and detached, and fine adjustments to the embedding hole 33 and the embedding portion 22 and confirmation of the connection state after the fine adjustments can be repeatedly performed. Therefore, the workability and connection accuracy when fixing the abutment 20 and the dental prosthesis 30 can be improved.

[0050] The dentist attaches the abutment 20, to which the dental prosthesis 30 has been adhesively fixed as described above, to the fixture 10 in the patient's oral cavity. Next, the dentist inserts a screw 40 through the through-hole 32 of the dental prosthesis 30 and the screw insertion hole 21a of the abutment 20, and screws the male thread portion 41 of the screw 40 into the screw hole 14 of the fixture 10, thereby fixing the abutment 20 and the dental prosthesis 30 to the fixture 10. After that, the dentist fills the through-hole 32 and the screw insertion hole 21a with a filler such as silicone, thermo-reversible resin, composite resin, or ceramic, and seals these holes, thereby completing the implant treatment.

[0051] As described above, according to the first embodiment of the abutment 20, dental prosthesis 30, connection structure between the abutment 20 and the dental prosthesis 30, and dental implant 100, the positioning of the abutment 20 and the dental prosthesis 30 can be easily and appropriately performed, and displacement of the dental prosthesis 30 relative to the abutment 20 can be appropriately prevented.

[0052] As a result, when the dental implant 100 is used, it is possible to appropriately prevent misalignment such as rotation of the dental prosthesis 30, and it is possible to provide an abutment 20, a dental prosthesis 30, a connection structure between the abutment 20 and the dental prosthesis 30, and a dental implant 100 that are excellent in usability and durability.

[0053] (Variations 1 to 8) Next, the abutments 20A to 20H according to Modifications 1 to 8 will be described with reference to Figures 6 to 13. The abutments 20A to 20H according to Modifications 1 to 8 have the same basic configuration as the abutment 20 of the first embodiment, except that the configuration of the flat surface 23 or the spring member 24 is different. For this reason, the following will mainly describe the configuration that differs from the abutment 20 of the first embodiment. Note that the dental prosthesis 30 to be fixed to the abutments 20A to 20H according to Modifications 1 to 8 is designed and processed to have an embedding hole 33 on which is formed abutment surfaces 35 that correspond to the flat surfaces 23 of the abutments 20A to 20H according to Modifications 1 to 8.

[0054] Fig. 6 is a perspective view of an abutment 20A of Modified Example 1. In the abutment 20 of the first embodiment described above, the outer periphery of the implantation portion 22 is cut out from near the base 21 to the upper end to form a substantially rectangular first flat surface 23a and second flat surface 23b. In contrast, in the abutment 20A of Modified Example 1 shown in Fig. 6, the outer periphery is not cut out all the way to the upper end, and part of the outer periphery is cut out in an arc shape to form sail-shaped (triangular) first flat surface 23a and second flat surface 23b.

[0055] In an abutment 20B of Modified Example 2 shown in Fig. 7, the circumferential distance between the first flat surface 23a and the second flat surface 23b is wider than the distance between these surfaces in the abutment 20 of the first embodiment. In an abutment 20C of Modified Example 3 shown in Fig. 8, the axial lengths of the first flat surface 23a and the second flat surface 23b are shorter than those of the abutment 20 of the first embodiment.

[0056] With the abutments 20A, 20B, and 20C of the above-mentioned variants 1 to 3, the dental prosthesis 30 can be guided to the appropriate position (the position where the flat surface 23 and the abutment surface 35 abut) in the circumferential direction (rotational direction) by the biasing force of the spring member 24 and the flat surface 23, thereby enabling appropriate alignment.

[0057] FIG. 9 shows a side view and a rear view of an abutment 20D of Modification 4. The abutment 20D of Modification 4 differs from the abutment 20 of the first embodiment in the position at which the spring member 24 is connected to the main body of the implanted portion 22. Specifically, the abutment 20 of the first embodiment is formed by cutting out a rectangular shape in the wall of the implanted portion 22 from the base 21 side toward the tip, and the base 21 side (rear end side) of the spring member 24 is connected to the main body of the implanted portion 22. In contrast, the abutment 20D of Modification 4 has a rectangular cutout in the wall from the tip side toward the base 21 side, and the spring member 24 is connected to the main body of the implanted portion 22 at the tip side of the implanted portion 22. Even with this configuration, the spring member 24 biases the implanted portion 22 in a direction that presses the flat surface 23 against the abutment surface 35, enabling appropriate alignment. Furthermore, when inserting the embedding portion 22 into the embedding hole 33, the spring member 24 is pushed by the inner surface of the embedding hole 33 without having to be pushed by hand, and the spring member 24 moves in the direction (inner diameter direction) to be accommodated in the accommodation portion 25, thereby enabling smoother insertion.

[0058] An abutment 20E of Modified Example 5 shown in Fig. 10 has only one flat surface 23 that faces the spring member 24. An abutment 20F of Modified Example 6 shown in Fig. 11 has three flat surfaces 23 (first flat surface 23a, second flat surface 23b, and third flat surface 23c), with the second flat surface 23b being arranged facing the spring member 24 and the first flat surface 23a and the third flat surface 23c being arranged on both sides of the second flat surface 23b in plane symmetry. An abutment 20G of Modified Example 7 shown in Fig. 12 has four flat surfaces 23 (first flat surface 23a, second flat surface 23b, third flat surface 23c, and fourth flat surface 23d), with the first flat surface 23a and second flat surface 23b and the third flat surface 23c and fourth flat surface 23d being arranged in plane symmetry.

[0059] An abutment 20H of Modification 8 shown in FIG. 13 has two flat surfaces 23 (a first flat surface 23a and a second flat surface 23b), but the first flat surface 23a and the second flat surface 23b have different sizes (width and thickness). More specifically, in the abutment 20 of the first embodiment, the first flat surface 23a and the second flat surface 23b are formed symmetrically. In contrast, in Modification 8, the first flat surface 23a and the second flat surface 23b are formed asymmetrically. The first flat surface 23a has a width wider than the second flat surface 23b and is formed by cutting out a large portion of the wall surface, and therefore is thinner than the second flat surface 23b.

[0060] The abutments 20E to 20H according to the above-mentioned variants 5 to 8 can also guide the dental prosthesis 30 to an appropriate position (position where the flat surface 23 and the abutment surface 35 abut) in the circumferential direction (rotational direction) by the biasing force of the spring member 24 and one or more flat surfaces 23, thereby enabling appropriate alignment.

[0061] The abutments 20A to 20H according to the above-described first to eighth modifications can be used as the abutment of the dental implant 100 of the first embodiment in place of the abutment 20 of the first embodiment.

[0062] Although the embodiments and modifications of the present disclosure have been described in detail above with reference to the drawings, the above embodiments and modifications are merely examples of the present disclosure, and the present disclosure is not limited to the configurations of the above embodiments and modifications. Of course, any design changes that do not deviate from the gist of the present disclosure are also included in the present disclosure.

[0063] For example, in the above embodiment and each modified example, the spring member 24 is a leaf spring formed by cutting out a rectangular portion of the wall surface of the embedding portion 22, but is not limited to this. For example, a leaf spring manufactured separately from the embedding portion 22 or a commercially available leaf spring may be fixed to the outer periphery of the embedding portion 22 by welding, adhesive, or the like, or may be attached to the outer periphery of the embedding portion 22 by an appropriate attachment member such as a metal fitting. Furthermore, the embedding portion 22 has a housing portion 25 that houses the spring member 24 when inserted into the embedding hole 33, but the housing portion 25 is not necessarily provided, and the spring member 24 may be layered on the outer periphery of the embedding portion 22.

[0064] Furthermore, the spring member 24 is not limited to a leaf spring, but may be any member capable of biasing the embedded portion 22 in a direction that presses the flat surface 23 against the contact surface 35. For example, as another different example, the spring member 24 may be a coil spring, a torsion spring, a power spring, or an elastic body such as rubber.

[0065] Furthermore, the abutments 20 to 20H of the above-described embodiment and each modified example can be used by fixing an existing dental prosthesis. Specifically, an existing dental prosthesis can be used in which a flat surface corresponding to the abutment surface is formed in the embedding hole. The fabricator fabricates the embedding portion of the abutment 20 to 20H by providing a flat surface and a spring member to match the dimensions of the embedding hole of such an existing dental prosthesis. As a result, when the embedding portion is inserted into the embedding hole, the above-described action of the flat surface and the spring member allows the existing dental prosthesis and the abutment 20 to 20H to be properly aligned. [Explanation of symbols]

[0066] 1: Alveolar bone 10: Implant fixture 20~20H: Dental abutment 21: Base 22: Implantation part 23: Flat surface 23a: First flat surface 23b: Second flat surface 23c: Third flat surface 23d: Fourth flat surface 24: Spring member 30: Dental prosthesis 33: Embedding hole 35: Contact surface 35a: First contact surface 35b: Second contact surface 100: Dental implant

Claims

1. A dental abutment having a base portion fixed to an implant fixture that is embedded in an alveolar bone and an embedding portion fixed to an embedding hole provided in a dental prosthesis, The embedding portion has at least one flat surface provided on an outer periphery and a spring member, the flat surface is configured to have a first flat surface and a second flat surface provided by cutting out a rectangular shape from the outer periphery of the embedded portion along the axis of the embedded portion, the first flat surface and the second flat surface and the spring member are provided opposite each other with the central axis of the embedded portion in between, and when the distance between the end point A and the end point B on the side closer to the spring member among two end points A and C of one side of the axial direction of the first flat surface and two end points B and D of one side of the axial direction of the second flat surface is α and the distance between the end point C and the end point D on the side farther from the spring member is β, α>β is satisfied, a first contact surface and a second contact surface corresponding to the first flat surface and the second flat surface are provided in the embedding hole; The spring member biases the embedding portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutting surface and the second abutting surface when the embedding portion is inserted into the embedding hole. A dental abutment characterized by:

2. The spring member is a leaf spring that is arranged along the axial direction of the implanted portion and is movable in the outer and inner radial directions of the implanted portion. The dental abutment according to claim 1 .

3. The leaf spring is made of an elastically deformable material with a Young's modulus of 200 GPa or less. The dental abutment according to claim 2 .

4. The flat surface is provided in plurality on the outer periphery of the implantation portion. The dental abutment according to claim 1 .

5. A dental prosthesis fixed via a dental abutment to an implant fixture that is implanted into alveolar bone, The dental abutment includes an embedding portion having at least one flat surface provided on an outer periphery and a spring member and being fixed to the dental prosthesis; the flat surface is configured to have a first flat surface and a second flat surface provided by cutting out a rectangular shape from the outer periphery of the embedded portion along the axis of the embedded portion, the first flat surface and the second flat surface and the spring member are provided opposite each other with the central axis of the embedded portion in between, and when the distance between the end point A and the end point B on the side closer to the spring member among two end points A and C of one side of the axial direction of the first flat surface and two end points B and D of one side of the axial direction of the second flat surface is α and the distance between the end point C and the end point D on the side farther from the spring member is β, α>β is satisfied, the dental prosthesis has a first abutment surface and a second abutment surface corresponding to the first flat surface and the second flat surface, and includes an embedding hole into which the embedding portion is inserted; The spring member biases the embedding portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutting surface and the second abutting surface when the embedding portion is inserted into the embedding hole. A dental prosthesis characterized by:

6. A connection structure for a dental abutment used in a dental implant and a dental prosthesis, The dental abutment includes an embedding portion having at least one flat surface provided on an outer periphery and a spring member and being fixed to the dental prosthesis; the flat surface is configured to have a first flat surface and a second flat surface provided by cutting out a rectangular shape from the outer periphery of the embedded portion along the axis of the embedded portion, the first flat surface and the second flat surface and the spring member are provided opposite each other with the central axis of the embedded portion in between, and when the distance between the end point A and the end point B on the side closer to the spring member among two end points A and C of one side of the axial direction of the first flat surface and two end points B and D of one side of the axial direction of the second flat surface is α and the distance between the end point C and the end point D on the side farther from the spring member is β, α>β is satisfied, the dental prosthesis has a first abutment surface and a second abutment surface corresponding to the first flat surface and the second flat surface, and includes an embedding hole into which the embedding portion is inserted; The spring member biases the embedding portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutting surface and the second abutting surface when the embedding portion is inserted into the embedding hole. A connecting structure for a dental abutment and a dental prosthesis, characterized in that:

7. A dental implant comprising an implant fixture, a dental abutment, and a dental prosthesis, The dental abutment includes a base portion fixed to the implant fixture; an implant portion fixed to the dental prosthesis; The embedding portion has at least one flat surface provided on an outer periphery and a spring member, the flat surface is configured to have a first flat surface and a second flat surface provided by cutting out a rectangular shape from the outer periphery of the embedded portion along the axis of the embedded portion, the first flat surface and the second flat surface and the spring member are provided opposite each other with the central axis of the embedded portion in between, and when the distance between the end point A and the end point B on the side closer to the spring member among two end points A and C of one side of the axial direction of the first flat surface and two end points B and D of one side of the axial direction of the second flat surface is α and the distance between the end point C and the end point D on the side farther from the spring member is β, α>β is satisfied, the dental prosthesis has a first abutment surface and a second abutment surface corresponding to the first flat surface and the second flat surface, and includes an embedding hole into which the embedding portion is inserted; The spring member biases the embedding portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutting surface and the second abutting surface when the embedding portion is inserted into the embedding hole. A dental implant characterized by:

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