JP7817889B2 - Dental abutment, dental prosthesis, connection structure between dental abutment and dental prosthesis, and dental implant - Google Patents

Description

The present disclosure relates to dental abutments, dental prostheses, connection structures between dental abutments and dental prostheses, and dental implants.

Technology related to dental implants is known 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).

Patent Document 1 discloses a technology in which, when the implantation portion of an abutment is inserted into the implantation hole of a dental prosthesis, a first flat surface formed on the inner circumferential surface of the implantation hole corresponds to a second flat surface formed on the outer circumferential surface of the implantation portion, and a protrusion formed on the implantation hole is cut, thereby positioning the dental prosthesis and abutment, firmly connecting and fixing the abutment to the dental prosthesis and preventing misalignment, such as rotation.

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 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, thereby fixing the dental prosthesis to the abutment and preventing the dental prosthesis from moving.

However, with the conventional technology described in Patent Document 1, the protrusions are cut when the dental prosthesis and abutment are fixed together, meaning that redoing is not possible and dental technicians and other professionals must have a high level of skill. Furthermore, because the protrusions cannot be repaired, dental prostheses sometimes have to be remade in cases where excessive cutting is required. Furthermore, with the conventional technology described in Patent Document 2, the abutment and dental prosthesis are not fixed together until the screw part is attached, meaning that unexpected misalignment may occur during the attachment process to the fixture. Furthermore, because the structure of the expansion section is complex and there are many parts, manufacturing and assembling 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 expansion section, making the machining of the dental prosthesis also cumbersome.

International Publication No. 2017/169037 Special table 2019-529047 publication

This disclosure has been made in response to the above-mentioned problems, and aims to enable easy and appropriate positioning of the abutment and dental prosthesis, and to appropriately prevent misalignment of the dental prosthesis relative to the abutment.

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 to be 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, wherein the dental abutment includes an implant portion having at least one flat surface provided on an outer periphery and a spring member and fixed to the dental prosthesis, the dental prosthesis includes an implant hole having an abutment surface corresponding to the flat surface and into which the implant portion is inserted, and the spring member biases the implant portion in a direction in which the flat surface is pressed against the abutment surface when the implant portion is inserted into the implant 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 provided on an 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 provided on an 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.

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 while being pressed against the abutment surface. This allows the abutment and dental prosthesis to be properly positioned, while preventing relative movement between them in the rotational direction. Therefore, the abutment and dental prosthesis can be easily and properly positioned, and displacement of the dental prosthesis relative to the abutment can be properly prevented.

FIG. 1 is an exploded view of a dental implant according to a first embodiment. FIG. 1 is a cross-sectional view showing a state in which the dental implant according to the first embodiment is used. 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. 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. 1A and 1B are explanatory diagrams for explaining a preferred configuration of the first and second flat surfaces and the spring member, in which (a) is a diagram showing a preferred positional relationship between the first and second flat surfaces and the spring member, and (b) is a diagram showing the 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. FIG. 10 is a perspective view of an abutment of a modified example 1. FIG. 10 is a perspective view of an abutment of Modified Example 2. FIG. 10 is a perspective view of an abutment of modified example 3. 10A and 10B are a side view and a rear view of an abutment of Modified Example 4. FIG. 10 is a plan view of an abutment of modified example 5. FIG. 13 is a plan view of an abutment of modified example 6. FIG. 13 is a plan view of an abutment of modified example 7. FIG. 13 is a plan view of an abutment of modified example 8.

(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.

First, the configuration of the 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.

The fixture 10 is embedded in an implant cavity 2 formed in the alveolar bone 1 (see Figure 2) of the 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 closed at one end (rear end) that is inserted into the implant cavity 2, and open at the other end (tip end) where the abutment 20 is attached. It is provided with an engagement hole 13 into which the base 21 of the abutment 20 (described below) is fitted and fixed, and a screw hole (female thread) 14 into which the male thread portion 41 of the screw 40 is threaded.

The fixture 10 configured in this manner is fixed to the alveolar bone 1 by being screwed into an implant socket 2 formed in the tooth-missing portion of the alveolar bone 1. However, the fixture 10 is not limited to this configuration, and can 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.

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.

Hereinafter, in this specification, the direction along the axis of the implant 100 and its constituent parts (fixture 10, abutment 20, dental prosthesis 30) 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, in the case of a tooth or dental prosthesis 30, the surface that faces the tongue will be referred to as the lingual surface, and the surface that faces the opposite direction to the tongue, i.e., toward the lips or cheeks (hereinafter referred to as the "labio-buccal direction") will be referred to as the labio-buccal surface.

Next, the configuration of the abutment 20 will be described with reference to Figure 3. The abutment 20 has a base 21 and an implantation portion 22. The base 21 has a screw insertion hole 21a and 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.

The embedding portion 22 has a screw receiving hole 22a, is larger in diameter than the base portion 21, and is a cylindrical member with a rectangular or trapezoidal cross-section along its axis. The embedding portion 22 is inserted into the embedding hole 33 of the dental prosthesis 30 (described below) and fixed with a dental adhesive such as cement. The inner diameter of the screw receiving hole 22a is larger than the inner diameter of the screw insertion hole 21a and is large enough to receive 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 receiving hole 22a) to engage with the head 42 of the screw 40 placed in the screw receiving hole 22a.

The embedding portion 22 also has two flat surfaces 23 on its outer periphery, namely, 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, they will simply be referred to as flat surfaces 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 generally rectangular shape along the axis of the embedding portion 22, resulting in an inwardly recessed shape (inner diameter direction, from the outside toward the center). Such first flat surface 23a and 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, this is not limited to this, and they may also be formed using a formwork or the like having flat surfaces corresponding to the first flat surface 23a and the second flat surface 23b.

The flat surface 23 is not limited to this notch shape, and may have other different shapes, such as a shape in which part of the outer peripheral surface of the embedded portion 22 protrudes outward (in the outer radial direction, from the center to the outside), as long as a flat surface is formed relative to the curved outer peripheral surface of the main body of the embedded portion 22.

The circumferential length (width) of the first flat surface 23a and the second flat surface 23b is preferably 1 mm or more. Furthermore, the thickness of the first flat surface 23a and the second flat surface 23b is preferably 0.4 mm or more. By using these dimensions, the abutment 20 and the dental prosthesis 30 can be properly positioned by the first flat surface 23a and the second flat surface 23b, and the strength of the abutment 20 can be properly 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.

The spring member 24 is a leaf spring arranged along the axial direction of the embedded portion 22, movable in the outer and inner diameter directions of the embedded portion 22, and biases the embedded portion 22 in a direction pressing it against the inner surface of the embedded 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 embedded 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 embedded portion 22. The spring member 24 is bent outward (in the outer diameter direction) around a valley fold near this fixed end, forming a free end at the tip 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 from the tip, with no cutout on the tip side of the wall of the embedded portion 22; however, the spring member 24 may also be formed by cutting out the wall of the embedded portion 22 all the way to the tip, and can be selected appropriately based on ease of manufacture, material, etc.

The 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. The embedding portion 22 also has an annular flange 26 at its rear end (toward the base 21) that protrudes outward (in the outer radial direction). The rear end of the dental prosthesis 30 is positioned against this flange 26, which functions as a support and stopper for supporting the dental prosthesis 30. The rear end of the embedding portion 22 also serves as an abutment portion 27 that abuts against the tip of the fixture 10.

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). Furthermore, 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.

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 materials, the abutment 20 has excellent strength, durability, and biocompatibility, and is able to suppress deterioration such as rust. Furthermore, the spring member 24 has excellent shape memory properties and can maintain an appropriate biasing force through elastic deformation.

Next, a preferred configuration of the flat surface 23 and spring member 24 will be described with reference to Figure 5, but this configuration is not limited to that shown in Figure 5. The flat surface 23 and spring member 24 are preferably arranged 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.

Furthermore, as in this embodiment, the flat surface 23 is preferably composed of two (a pair of) flat surfaces 23, namely, a first flat surface 23a and a second flat surface 23b, formed by cutting out a rectangular shape from the outer periphery of the implantation portion 22 along the axis of the implantation 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 implantation hole 33, described below, respectively, thereby more appropriately positioning the abutment 20 and the dental prosthesis 30.

Furthermore, when the distance between the two end points A and C of one axial side (the side closest to the tip) of the first flat surface 23a and the two end points B and D of one axial side (the side closest to 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) be satisfied.

α＞β (1)

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 arranged symmetrically across a plane including the central axis I of the implantation portion 22 and the circumferential center J of the spring member 24.

By adopting 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, along with the plane-symmetrical first flat surface 23a and second flat surface 23b, guides the dental prosthesis 30, while rotating in either a clockwise or counterclockwise direction, to a position where the first flat surface 23a and the second flat surface 23b abut against the first abutment surface 35a and the second abutment surface 35b, respectively, i.e., to the optimal position (best position). As a result, the first flat surface 23a and the second flat surface 23b are pressed against and abut against the first abutment surface 35a and the second abutment surface 35b, respectively, more appropriately positioning the abutment 20 and the dental prosthesis 30 and more appropriately preventing misalignment in the rotational direction.

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

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

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

The embedding hole 33 is a cylindrical hole provided at the rear end 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 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.

The embedding hole 33 is the surface that abuts against the flat surface 23 of the abutment 20, and is provided with an abutment surface 35 formed with a flat shape that corresponds to this 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.

The inner surface shape of the embedding hole 33, including the portions other than the first and second contact surfaces 35a and 35b, is formed to correspond to the outer surface shape of the embedding portion 22. In other words, the embedding hole 33 is formed with a shape and dimensions that allow the embedding portion 22, with the spring member 24 housed in the housing portion 25, to fit therein, and the first and second flat surfaces 23a and 23b to contact the first and second contact surfaces 35a and 35b.

The inner shape of the embedding hole 33 does not have to be formed to precisely match 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, effectively expanding the outer diameter of the embedding portion 22, and the spring member 24 presses the main body 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, suppressing relative rotation and wobbling between the dental prosthesis 30 and the abutment 20 and accommodating manufacturing tolerances.

The procedures for fabricating a dental implant 100 configured as described above and for implant treatment will now be described. First, when fabricating the dental prosthesis 30, the 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 creates 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 other tool and creates a digital model.

Next, the fabricator uses a digital model created using analog or digital impression techniques to design the outer and inner surface shapes of the dental prosthesis 30 using dental CAD software. The abutment 20 that secures 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 into the dental CAD software in advance, the fabricator or system technician can generate design data for the inner surface shape of the embedding hole 33 with the first and second contact surfaces 35a and 35b in the dental CAD software.

Then, the fabricator loads this design data into CAM software, generates NC data through calculations, attaches a ceramic block, for example, to a cutting machine, and uses a cutting tool under computer control to cut the ceramic block. This produces the dental prosthesis 30 of the first embodiment, which includes an embedding hole 33 having a first contact surface 35a and a second contact surface 35b.

Teeth have a labio-buccal surface facing in the labio-buccal direction and a lingual surface positioned in the lingual direction, and the dental prosthesis 30 also has a labio-buccal surface and a lingual surface. In light of this, it is preferable to provide the dental prosthesis 30 with 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 attached is secured to the fixture 10, the abutment surface 35 and the flat surface 23 are positioned on the labio-buccal side and facing in the labio-buccal direction. This distributes the biasing force of the spring member 24 across the labio-buccal surface of the dental prosthesis 30, reducing the load on the dental prosthesis 30. Furthermore, abutment between the abutment surface 35 and the flat surface 23 appropriately prevents 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 they may be positioned to face in any direction depending on the treatment procedure and ease of operation.

1 and 2 show a dental prosthesis 30 for back teeth (molars), which has an abutment surface 35 (see FIG. 1) on the labio-buccal side of the dental prosthesis 30. In contrast, FIG. 4 shows a dental prosthesis 30 for front teeth (incisors). (a) of FIG. 4 shows a dental prosthesis 30 for front teeth to which an abutment 20 is fixed. A first abutment surface 35a and a second abutment surface 35b are provided on the labio-buccal side of the dental prosthesis 30, with the first flat surface 23a and the second flat surface 23b of the abutment 20 abutting against these, respectively. (b) of FIG. 4 is a bottom view of the dental prosthesis 30 for front teeth, which has an insertion hole 33 with a first abutment surface 35a and a second abutment surface 35b on the labio-buccal side and an inner surface shaped to correspond to the outer surface of the insertion portion 22.

The abutment 20 and dental prosthesis 30 prepared as described above are fixed to the fixture 10 fitted into the patient's alveolar bone 1, thereby performing implant treatment for the missing tooth. To do this, a dentist or other professional first applies a dental adhesive such as cement to the outer surface of the implant portion 22 of the abutment 20 and the inner surface of the implant hole 33 of the dental prosthesis 30, inserts the implant portion 22 into the implant hole 33, and adhesively fixes the dental prosthesis 30 to the abutment 20.

However, with conventional technology, there were problems such as the protrusion being cut off when the implantation part was inserted into the implantation hole, making it impossible to redo the process, and the abutment and dental prosthesis not being fixed together until the screw part for fixing to the fixture was attached.

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. This configuration in the first embodiment can solve the above problem.

When adhesively fixing the abutment 20 and dental prosthesis 30 of the first embodiment, the dentist or other professional pushes the spring member 24 in the inner diameter direction to store it in the storage portion 25. When the implantation portion 22 is inserted into the implantation hole 33 in this state, the spring member 24 returns to its original shape and moves in the outer diameter direction, biasing the implantation portion 22. As a result, the implantation portion 22 is guided in the circumferential direction (rotational direction) toward 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. This allows the first flat surface 23a and the second flat surface 23b to abut against the first abutment surface 35a and the second abutment surface 35b quickly and accurately, without the dentist or other professional having to perform precise manual alignment.

In addition, even if there are manufacturing tolerances in the embedding portion 22 and the embedding hole 33, the biasing 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, suppressing relative rotation or wobbling between the abutment 20 and the dental prosthesis 30.

In addition, because the abutment 20 and dental prosthesis 30 can be positioned and fixed using the biasing force of the spring member 24, a dental technician can temporarily connect (temporarily fasten) the abutment 20 and dental prosthesis 30 before applying adhesive, for example, to check the state of their connection. Furthermore, the abutment 20 and dental prosthesis 30 can be easily attached and detached, and fine adjustments to the embedding hole 33 and embedding portion 22 and confirmation of the connection state after fine adjustments can be repeatedly performed. This improves the ease of use and connection accuracy when fixing the abutment 20 and dental prosthesis 30.

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 mouth. 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 threads the male thread portion 41 of the screw 40 into the screw hole 14 of the fixture 10, thereby fixing the abutment 20 and dental prosthesis 30 to the fixture 10. The dentist then fills the through-hole 32 and the screw insertion hole 21a with a filler such as silicone, thermoplastic resin, composite resin, or ceramic, and seals these holes, completing the implant treatment.

As described above, the abutment 20, dental prosthesis 30, connection structure between the abutment 20 and the dental prosthesis 30, and dental implant 100 of the first embodiment allow for easy and appropriate positioning of the abutment 20 and the dental prosthesis 30, and appropriately prevents misalignment of the dental prosthesis 30 relative to the abutment 20.

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 to provide an abutment 20, dental prosthesis 30, connection structure between the abutment 20 and the dental prosthesis 30, and dental implant 100 that are easy to use and durable.

(Modifications 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.

Figure 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, the abutment 20A of Modified Example 1 shown in Figure 6 does not cut out the outer periphery all the way to the upper end, and instead cuts out a portion of the outer periphery so that it forms an arc, forming a sail-shaped (triangular) first flat surface 23a and second flat surface 23b.

In the abutment 20B of modified example 2 shown in Figure 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 the abutment 20C of modified example 3 shown in Figure 8, the axial lengths of the first flat surface 23a and the second flat surface 23b are shorter than the lengths of these surfaces in the abutment 20 of the first embodiment.

Even with the abutments 20A, 20B, and 20C of variants 1 to 3 described above, the biasing force of the spring member 24 and the flat surface 23 can guide the dental prosthesis 30 to the appropriate position in the circumferential direction (rotational direction) (the position where the flat surface 23 and the abutment surface 35 abut), enabling proper alignment.

Figure 9 shows a side view and a rear view of an abutment 20D of Variation 4. The abutment 20D of Variation 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 has a wall surface of the implanted portion 22 cut out in a rectangular shape from the base 21 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 Variation 4 has a wall surface cut out in a rectangular shape from the tip toward the base 21, 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 proper alignment. Furthermore, when inserting the embedding portion 22 into the embedding hole 33, the spring member 24 does not need to be pushed by hand; instead, it is pushed by the inner surface of the embedding hole 33, causing the spring member 24 to move in the direction (inner diameter direction) in which it is housed in the housing portion 25, allowing for smoother insertion.

Abutment 20E of modified example 5 shown in Figure 10 has only one flat surface 23 facing the spring member 24. Abutment 20F of modified example 6 shown in Figure 11 has three flat surfaces 23 (first flat surface 23a, second flat surface 23b, and third flat surface 23c), with second flat surface 23b positioned facing the spring member 24 and first flat surface 23a and third flat surface 23c positioned on either side of second flat surface 23b in plane symmetry. Abutment 20G of modified example 7 shown in Figure 12 has four flat surfaces 23 (first flat surface 23a, second flat surface 23b, third flat surface 23c, and fourth flat surface 23d), with first flat surface 23a and second flat surface 23b and third flat surface 23c and fourth flat surface 23d positioned in plane symmetry.

The abutment 20H of variant 8 shown in Figure 13 has two flat surfaces 23 (first flat surface 23a and second flat surface 23b), but the first flat surface 23a and 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 variant 8, the first flat surface 23a and the second flat surface 23b are formed asymmetrically. The first flat surface 23a is wider than the second flat surface 23b and is formed by cutting out a large portion of the wall, so it is also thinner than the second flat surface 23b.

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

The abutments 20A to 20H according to the above-described variants 1 to 8 can be used as the abutments of the dental implant 100 of the first embodiment in place of the abutment 20 of the first embodiment.

The above describes in detail the embodiments and variations of the present disclosure with reference to the drawings. However, the above embodiments and variations are merely examples of the present disclosure, and the present disclosure is not limited to the configurations of the above embodiments and variations. Naturally, any design changes that do not deviate from the gist of the present disclosure are also included in the present disclosure.

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 this 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, etc., or may be attached to the outer periphery of the embedding portion 22 with an appropriate attachment member such as metal fittings. 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 configured to be layered on the outer periphery of the embedding portion 22.

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, rubber, or other elastic body.

Furthermore, the abutments 20-20H of the above embodiments and modified examples can be used to secure existing dental prostheses. Specifically, existing dental prostheses can be used that have a flat surface corresponding to the abutment surface formed in the embedding hole. The fabricator fabricates the embedding portion of the abutments 20-20H by providing a flat surface and spring member that are sized to fit the embedding hole of such existing dental prostheses. In this way, when the embedding portion is inserted into the embedding hole, the above-described action of the flat surface and spring member allows for proper alignment of the existing dental prosthesis and the abutments 20-20H.

1: Alveolar bone 10: Implant fixture 20-20H: Dental abutment 21: Base 22: Embedding portion 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 (7)

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;
A dental abutment characterized in that, when the embedded portion is inserted into the embedded hole, the spring member urges the embedded portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutment surface and the second abutment surface . 2. The dental abutment according to claim 1, wherein the spring member is a leaf spring that is arranged along the axial direction of the implantation portion and is movable in the outer and inner radial directions of the implantation portion. 3. The dental abutment according to claim 2, wherein the leaf spring is made of an elastically deformable material having a Young's modulus of 200 GPa or less. The dental abutment according to claim 1 , wherein a plurality of the flat surfaces are provided on the outer periphery of the implantation portion. 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;
A dental prosthesis characterized in that, when the embedded portion is inserted into the embedded hole, the spring member urges the embedded portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutment surface and the second abutment surface . 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;
A connection structure for a dental abutment and a dental prosthesis, characterized in that when the embedded portion is inserted into the embedded hole, the spring member urges the embedded portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutment surface and the second abutment surface . 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;
A dental implant characterized in that, when the embedded portion is inserted into the embedded hole, the spring member urges the embedded portion in a direction in which the first flat surface and the second flat surface are pressed against the first abutment surface and the second abutment surface .