JP7436966B2 - 2-piece dental implant - Google Patents

Description

The present invention relates to a two-piece type dental implant.

An artificial tooth root as a tooth replacement is a one-piece method in which a core material is buried in the forehead bone, and then the denture is attached to the core that is exposed on the surface (the abutment part that constructs the superstructure). There are two types: one type and the two-piece type, in which the part to be implanted in the alveolar bone and the part to which the denture is attached are separated.

After the implant is placed in the alveolar bone, the upper structure of the one-piece type protrudes during the period of rest until it fuses with the bone, which may destroy the initial fixation due to occlusion or cause infection from the fixation site. Therefore, a two-piece type that does not protrude upward during the period of rest may be preferable.

If it has been a while since a tooth has fallen out, or if there is bone loss due to periodontal disease, etc., bone replacement materials such as crushed autologous bone, artificial aggregate (ceratite), and β-tricalcium phosphate can be used to supplement the bone. Then, an artificial membrane is placed on top of the membrane and left to stand for 4 to 6 months to perform replacement bone regeneration (GBR: guided bone regeneration method), or when replacing bone substitute material, dental implants are placed together. It may be covered with an artificial membrane. In addition, in the case of implants in the maxilla, if there is less bone, the implant cannot be placed in the maxillary sinus, so bone filling materials such as artificial bone are placed between the jawbone of the maxilla and the Schneider's membrane that covers the maxillary sinus. In some cases, the implant is placed (sinus lift, socket lift).

Japanese Unexamined Patent Publication No. 2013-540001 discloses a fixture in which both a straight abutment and an inclined abutment can be attached. Japanese Patent Application Laid-Open No. 10-94549 describes a GBR performed at the same time as dental implant embedding, in which a shaped sheet is formed from polylactic acid, which is a biodegradable absorbent material, and this shaped sheet and a dental implant are integrated into one structure. ing. JP-A-2015-84796 discloses a rotation prevention function in which the joint surface between an abutment and a fixture is shaped like an arcuate gear.

JP-A-11-47259 describes that a core material surface is coated with crystalline hydroxyapatite by plasma spraying, and then subjected to hot water treatment and immersed in water to form a crystallized apatite layer. There is.

JP-A No. 2014-50610 discloses that the core material is coated with acicular and/or columnar hydroxyapatite crystals to improve osteogenic ability to the extent that bones grow, and to improve the bonding ability with the living body and improve short-term It has been proposed to combine them between

Japanese Patent Application Publication No. 2013-540001 Patent No. 6389578 Japanese Patent Application Publication No. 10-94549 Japanese Patent Application Publication No. 2015-84796 Japanese Patent Application Publication No. 11-47259 Japanese Patent Application Publication No. 2014-50610

For example, when placing an implant in an area with little bone between the maxillary sinus and the maxilla, bone prosthesis materials such as crushed pieces of autologous bone or artificial bone may be placed between the Schneider's membrane and the bone. The purpose is to replenish and thicken the bone and place an implant, or to regenerate bone tissue when bone loss occurs over time after tooth loss. When performing bone regeneration by supplementing with autologous bone fragments, bone prosthetic materials, and covering with an artificial membrane, bone replacement and regeneration takes time, and when an implant is subsequently placed, it takes even more time. When filling a bone-filling material into an implant-placed site with little bone, the implant may also be implanted, but the period of rest remains unchanged for four to six months.

In addition, in patients with diabetes, etc., the bone itself becomes soft, and in the case of metal materials that are not harmful to the body, such as implants, and biocompatible ceramic materials, the core material is originally hard and almost rod-shaped, so it may be difficult to bond with the bone. Implants that have low bonding properties and place a large burden on the bone at the implantation site may cause the implant to become embedded or sink into the maxillary sinus. Furthermore, since the use of autologous bone is a burden on the patient, it is preferable to limit the use of autologous bone to a smaller amount.

In addition, since it takes 4 to 6 months for the bone to be allowed to stand still for bone regeneration, a method has been proposed in which bone regeneration and implant stability are achieved at the same time by placing the implant at the same time as filling the bone filler. However, it is preferable to complete the procedure with just the implant placement.

In view of the above, the present invention includes a cylindrical threaded part, a radial inclined part that extends radially above the threaded part to a diameter larger than the maximum diameter of the threaded part, and a cylindrical shaped part with parallel side surfaces connected to the radial inclined part. A core material (fixture) consisting of a combination of parts, a core material covering part coated with needle-shaped and/or columnar hydroxyapatite crystals, and a mirror-polished part in contact with the gums , and a supersaturated solution containing phosphorus and calcium. A hydrothermal film is formed by hydrothermal treatment in In some cases, by selectively using a core material formed over almost the entire area of the core material, it is possible to prevent sinking into the alveolar bone, and to implant a dental implant without using bone replacement materials such as autologous bone. By simply adjusting the replacement volume in the area where bone is lacking, effective bone replacement is possible, and the acicular and/or columnar hydroxyapatite crystals integrate with the bone early, reducing the period of standing time. possible.

The core material (fixture) in the present invention has a coating layer composed of acicular and/or columnar hydroxyapatite crystals, and a portion other than the hydroxyapatite coating that contacts the gums is mirror-polished to remove phosphorus and calcium. It consists of a hydrothermal synthetic coating layer formed by immersion in a supersaturated aqueous solution containing: The core material, which is composed of a threaded part, a radially inclined part, and a cylindrical part, has a structure in which the volume increases toward the gingival direction, and in some cases, prostheses such as autologous bone used in GBR surgery may be unnecessary. This makes it possible to plant

Acicular and/or columnar hydroxyapatite coating layer In the acicular (columnar) hydroxyapatite coating layer of the present invention, the hydroxyapatite crystals are acicular and/or columnar (hexagonal columnar), and the length thereof is as follows: The implant surface, which has grown from about 2 μm to about 7 μm, is occupied in a certain direction by aligned crystal groups and radial crystal groups extending radially from the implant surface. Acicular (columnar) has a meaning that can be replaced with needle-like and/or columnar.

The method of forming an implant surface occupied by such a hydroxyapatite crystalline state is to use a material containing calcium phosphate compounds with different melting points to form a core material by plasma blasting based on the melting point temperature of the calcium phosphate compound with a low melting point. By the process of spray coating, a coating layer with sufficient bonding with the core material is obtained while allowing many crystal nuclei for recrystallization, and the crystal state after recrystallization is acicular and/or columnar. Surprisingly, bone formation from the implant surface was achieved by using crystals of a calcium phosphate compound with a length of 2 μm to 7 μm and covered with crystal arrays aligned in the same direction and radial crystals. By action. Immediate stabilization of implants after implantation.

The material of the main body is metal or ceramic materials such as titanium, titanium alloy, stainless steel, zirconia, partially stabilized zirconia, alumina, CaO-Na ₂ O-P ₂ O ₅ -SiO ₂ type glass (bioglass), and these materials. Among them, titanium and titanium alloys are preferred in terms of strength, biocompatibility, etc.

Calcium phosphate compounds that form the composite material as starting materials include various calcium phosphate compounds such as hydroxyapatite, tetracalcium phosphate, α-tricalcium phosphate, β-tricalcium phosphate, dicalcium phosphate, and dicalcium phosphate dihydrate. etc., but is limited to the above as long as it recrystallizes as hydroxyapatite after at least hydrothermal treatment and the implant surface becomes occupied by a plurality of aligned crystal groups and a plurality of radial crystal groups. isn't it.

Calcium phosphate compounds with different melting points in the present invention include, among the above-mentioned materials, a combination of tricalcium phosphate with a high melting point (1670° or higher) and hydroxyapatite with a low melting point (1650° or lower). Plasma spraying based on the melting point of a calcium phosphate compound with a low melting point refers to the plasma spraying conditions (types of various gases such as carrier gas, plasma gas, secondary gas, flow rate, pressure, temperature, etc.). , plasma output (for example, voltage, current, frequency, etc. for arc discharge) are adjusted to provide a heat amount that almost melts the low melting point calcium phosphate compound powder, and at that time, at least , which shows a state in which crystalline powder remains in the coated raw material powder made of a calcium phosphate compound with a high melting point.

Note that the above melting points are representative values, and in reality, the difference between the two melting points may be 100°C or more. In addition, after melting a calcium phosphate compound with a low melting point temperature by shortening the melting time while keeping the melting point temperature equal to or higher than that of the calcium phosphate compound with a high melting point temperature, the calcium phosphate compound with a high melting point temperature is completely melted. An example of this is the case where the melting is carried out until the time when many crystals of the raw material powder remain.

That is, a calcium phosphate compound with a low melting point is coated by plasma spraying to form a coating layer with high bonding properties, and the calcium phosphate compound with a high melting point is coated with crystals of the powdered raw material remaining in the coating layer. Any plasma spray that has been adjusted to form a contained state may be used. The calcium phosphate compound having a low melting point is preferably blended in a proportion of about 1% to 15% based on the total weight.

The plasma temperature during plasma discharge can be adjusted, for example, by adjusting the current, voltage, frequency, amount, type, and pressure of various gases, and by adjusting the amount and composition of alkali metals mixed in. The ionization may be performed using thermal plasma or the like whose degree of ionization is adjusted by adjusting the ionization degree. Similar effects can be expected to be obtained by adjusting the heat source when forming a spray coating by a method other than plasma spraying (high-speed flame spraying).

In addition, calcium phosphate compounds with a high melting point grow acicular and/or columnar crystals of hydroxyapatite through hydrothermal treatment, and are oriented on the implant surface in contact with the alveolar bone, creating aligned crystal arrays and a radial crystal state. Preferable examples include α-tricalcium phosphate and/or β-tricalcium phosphate. Hydrothermal treatment refers to treatment in which the coated core material is immersed in water, an aqueous solution in which phosphate ions and calcium ions coexist, or a calcium phosphate aqueous solution, or a steam atmosphere thereof, and then subjected to high temperature and high pressure. The hydrothermal treatment is preferably performed using an autoclave treatment device.

Phosphate ions coexisting in water during hydrothermal treatment are represented by _PO4 , and include calcium phosphate compounds such as hydroxyapatite, tricalcium phosphate, tetracalcium phosphate, and calcium hydrogen phosphate, as well as sodium dihydrogen phosphate, Examples include disodium hydrogen phosphate, dipotassium hydrogen phosphate, and ammonium phosphate. Examples of calcium ions include calcium carbonate, calcium chloride, calcium nitrate, calcium hydroxide, and the like, in addition to the above-mentioned calcium phosphate compounds. Also includes metals to which various ions such as Mg, Sr, Fe, Cr, Ti, Zr, Co, Mo, Al, Si, V, and F are added in consideration of corrosion resistance and chemical stability. do.

Further, in order to promote crystallization and crystal growth, it is preferable that the concentration of phosphate ions and calcium ions in the aqueous solution to be immersed and the atmosphere be supersaturated or locally supersaturated. An example of forming a supersaturated state is to administer calcium phosphate or the like to an aqueous solution to the extent that the concentrations of phosphate ions and calcium ions become supersaturated. The amount of water is preferably such that the coated molten calcium phosphate compound having a low melting point forms a supersaturated aqueous solution in the amount that is eluted. Further, the residue of the calcium phosphate composite material which has deviated from the core material during plasma melting may be added.

The treatment time is approximately 5 hours to 50 hours, preferably 7 hours to 28 hours, but may be adjusted as appropriate depending on the number of pieces to be treated, the thickness of the coating layer, the material, etc., and is not limited to this range.
By the hydrothermal treatment, crystal nuclei of the remaining or generated coating layer grow, and acicular and/or columnar (preferably hexagonal columnar) hydroxyapatite is formed.

The length of the crystals in the crystalline state of hydroxyapatite is preferably from 2 μm to 7 μm, and includes aligned crystal groups aligned along the core surface and radial crystal groups formed radially from the core surface. It is preferable that the two coexist and occupy the contact surface of the implant with the alveolar bone. The implant surface that comes into contact with the alveolar bone has been subjected to surface roughening treatment such as sandblasting in advance, so the alignment direction may follow the unevenness of the surface. Any alignment and radiation state of the crystals as shown is sufficient.

If the grown crystal is less than 2 μm, calcium phosphate compounds other than hydroxyapatite may remain, and if it is more than 7 μm, there is a high possibility that the crystal will break. In this way, crystal growth due to hydrothermal treatment is exemplified when the hydrothermal treatment time is around 7 to 28 hours, but it may be outside this range depending on the additives during hydrothermal treatment and the state of the coating layer. In some cases.
The temperature of the hydrothermal treatment is preferably 110° to 125°. If it is 110°, crystal growth will be insufficient, and if it is 125° or more, the coating layer will become brittle. The same can be said about the above-mentioned hydrothermal treatment time outside the range. Regarding the growth of crystals by hydrothermal treatment, for example, if the treatment time is increased, the crystals will grow more, but if the length of the crystals exceeds the above range, the crystals will grow too much, becoming brittle and peeling.

The recrystallized hydroxyapatite crystals formed in the region that contacts the bone tissue formed in the present invention have a needle shape and/or a columnar shape such as a hexagon, and grow in a certain direction and are aligned. They are arranged radially. This becomes a force for acquiring consistency (epitaxy) with collagen, and produces an osteogenic effect to the extent that bones grow. This is thought to provide the same osteogenic effect as the crushed autologous bone used in RGB surgery.
Specifically, osteoclasts differentiated from blood components form a surface where acicular and/or columnar pure recrystallized hydroxyapatite grows in a certain direction and is aligned, and a surface where radially formed regions are densely packed. It attaches to the tip of the crystal, dissolves and absorbs the crystal from that tip.

After dissolution and resorption of hydroxyapatite crystals by osteoclasts, osteoblasts begin to act based on signals or conditions caused by the osteoclasts. Osteoblasts act by entering into the gaps between hydroxyapatite crystals, deforming the crystals as the case may be, mainly in areas where osteoclasts have dissolved and absorbed acicular and/or columnar hydroxyapatite crystals.

Bone-related proteins such as osteopontin, osteocalcin, and bone sialoprotein secreted by osteoblasts, etc., and collagen, which has a fibrous form produced by osteoblasts, etc., are adsorbed in the gaps between needle-shaped and/or columnar hydroxyapatite crystals. accumulate. Furthermore, hydroxyapatite molecules are deposited on the surfaces of collagen fibers.

Some of the hydroxyapatite molecules deposited on the surfaces of collagen fibers form supersaturated "fields" caused by the dissolution of needle-shaped and/or columnar hydroxyapatite, causing hydroxyapatite crystals to precipitate early in the body. .
The deposited and precipitated hydroxyapatite plays a cement role, such as binding collagen fibers to each other, and binding newly formed crystalline apatite to acicular and/or columnar hydroxyapatite crystals, thereby forming the foundation of the bone. .
Furthermore, the osteoblasts that have formed new bone become osteocytes and are embedded in this base while the above-mentioned actions are repeated and the osteoblastic action of the new bone progresses. In this way, the implant surface formed by needle-shaped and/or columnar (hexagonal) hydroxyapatite crystals supports the functions of osteoblasts and the like, and serves as an excellent scaffold for forming new bone.
This bone-building action from the implant surface is performed together with the bone-building action from the alveolar bone side, thus achieving a rapid and strong bonding between the implant surface, bone tissue, and crushed autologous bone.

Regarding the hydrothermal film formed on the contact surface between the core material and the gums,
In order to remove minute irregularities on the surface, the surface of the metal material is preferably polished to a mirror surface after being polished using methods such as mechanical polishing, chemical polishing, electrolytic polishing, etc. using abrasive paper, surface buffing, roller burnishing, etc. After polishing, hydrothermal treatment (hydrothermal synthesis treatment) is performed in a supersaturated aqueous solution containing phosphorus and calcium components to form an oxide film (hydrothermal synthesis film) containing phosphorus and calcium components.

The hydrothermal synthesis treatment is preferably performed at the same timing as the hydrothermal treatment for recrystallization, which involves developing and growing hydroxyapatite crystals in the coating layer of the calcium phosphate composite material described above. The treatment time may be the same as, shorter than, or longer than the treatment time for the surface of the spray coating layer, but in order to keep the manufacturing process the same, it is preferable that the treatment be performed for the same time.

In the present invention, the core material is coated with a material containing calcium phosphate compounds having different melting points in a manner based on the melting point of calcium phosphate, which has a lower melting point among the calcium phosphate compounds, and then is recrystallized by hydrothermal treatment. By providing the ceramic coating, it is possible to promote osteogenic action from the implant surface and achieve early stabilization with the bone tissue. In addition, for the surface in contact with the gums, the surface from which minute irregularities have been removed by polishing is subjected to hydrothermal treatment in a state where the concentration of phosphate and calcium salt is supersaturated or locally supersaturated to form hydroxyapatite crystals or their crystal nuclei. By forming a film containing , a stable dental implant can be achieved by bonding with living tissue at an earlier stage.

Oxide film (hydrothermal synthetic film) is an aqueous solution containing water or calcium phosphate aqueous solution, phosphate ions and calcium ions coexisting during hydrothermal treatment, and the concentration of phosphoric acid etc. is supersaturated or locally supersaturated. By using a plasma spray coating layer, the growth of hydroxyapatite crystals can be promoted, and hydroxyapatite crystals can be formed on the contact surface with the gingiva.

Note that when immersing in water, the molten material generated when plasma spray coating is applied based on the melting point of the calcium phosphate compound with a low melting point in the composite material consisting of calcium phosphate compounds with different melting points will dissolve into the water. By reducing the amount of , a supersaturated or locally supersaturated calcium phosphate solution is formed.

This supersaturated or locally supersaturated aqueous calcium phosphate solution causes crystal nuclei present in the calcium phosphate compound coated by plasma blasting to grow, resulting in regions where needle-shaped and/or columnar hydroxyapatite crystals are aligned in the same direction and the implant surface. An oxide film (hydrothermal synthetic film) in which hydroxyapatite crystals can be formed is formed on the surface of the polished surface, which is the contact surface with the gingiva, forming regions extending radially outward.

For one implant core material with an alveolar bone implantation part, the gingival contact surface is polished so that there are no minute irregularities on the surface, and the surface is roughened by sandblasting, etc., and then coated with a calcium phosphate compound by plasma blasting. By performing hydrothermal treatment, regions of acicular and/or columnar hydroxyapatite crystals aligned in the same direction and regions extending radially outward from the implant surface are formed on the alveolar bone contact surface. Hydroxyapatite crystals and/or crystal nuclei are formed in the oxide film (hydrothermal synthetic film) on the contact surface with the gums.

The present invention is formed of a cylindrical threaded part, a radial inclined part that extends radially above the threaded part to a diameter larger than the maximum diameter of the threaded part, and a cylindrical part whose side surfaces are parallel and connected to the radial inclined part. The core material, whose volume is enlarged upward, facilitates fixation of the alveolar bone in the surface direction of the planting hole and the radial slope, allowing stable planting.
Furthermore, on the surface of the core material, a hydroxyapatite coating layer obtained by growing acicular (rod-shaped) hydroxyapatite crystals and a surface in contact with the gums are mirror-polished by immersion in a supersaturated solution of phosphoric acid and calcium. By selecting from multiple core materials (fixtures) whose supplementary volume is adjusted by increasing or decreasing the ratio of these coating layers in the resulting hydrothermal synthetic coating layer, it is possible to adapt to the planting hole space. In some cases, bone regeneration and implant placement can be performed at an early stage without the need for bone prosthetics.

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram for explaining an embodiment of the present invention.

The present invention is formed of a cylindrical threaded part, a radial inclined part that extends radially above the threaded part to a diameter larger than the maximum diameter of the threaded part, and a cylindrical part whose side surfaces are parallel and connected to the radial inclined part. The core material (cylindrical) has a spiral groove formed downward from the upper maximum diameter part to form a flat peak part and a flat valley part, and the upper part of the screw part 13 A radial inclined part 12 that extends radially at an angle of 25 degrees to 35 degrees with respect to the long axis direction of the fixture 10 from the maximum diameter part of the threaded part 13 to a diameter part larger than the maximum diameter part of the threaded part 13; A core material formed of a cylindrical portion 11 with parallel sides connected to a large diameter portion of the core material 11) , the core material has a threaded portion, a radially inclined portion, and a needle-shaped portion with different areas in the range of the cylindrical portion. By preparing a plurality of core materials each having a needle-shaped and/or a columnar crystallized hydroxyapatite coating layer formed thereon and/or a columnar crystallized hydroxyapatite coating layer, there is less alveolar bone in the patient's oral cavity. In this case, depending on the condition of the implantation site drilled into the alveolar bone, an appropriate core material can be selected and used from among the plurality of core materials with different areas of the covering layer of acicular and/or columnar crystallized hydroxyapatite. , the effective filling volume can be adjusted, there is no need for guided bone regeneration in areas where bone has been lost using bone filling materials such as autologous bone, and the bone construction has an acicular and/or columnar crystallized hydroxyapatite covering layer. This allows for early integration with bone.
The acicular and/or columnar crystallized hydroxyapatite coating layer has a structure as shown in the photograph shown in FIG. 6, for example.
The photographs shown in FIG. 6 are two photographs taken at the same magnification of different parts. By forming an oxidized film (hydrothermal synthetic film layer) on the other parts that contact the gums using a supersaturated aqueous solution of phosphoric acid and calcium, it is possible to implant implants that are optimal for alveolar bone defects. shall be. Furthermore, by forming the radially inclined part and the cylindrical part with a large volume, the radially inclined part with a large volume is fixed near the implantation hole drilled on the surface of the alveolar bone, which prevents the core material from sinking into the alveolar bone. prevent.
In addition, the use of autologous bone for alveolar bone regeneration is minimized, and the coating layer of needle-shaped (column-shaped) hydroxyapatite crystals quickly connects with the rapidly crushed autologous bone and surrounding bone tissue. Perform bone regeneration. In the present invention, one or more core materials (fixtures) having a needle-shaped and/or pillar-shaped crystallized hydroxyapatite coating layer are prepared in advance in an area corresponding to the amount of bone lost, and Use selectively. In addition, the radially inclined portion of the core material (fixture) disperses masticatory force, thereby preventing the buried implant from being buried, and preventing damage to the Schneider's membrane in cases such as a sinus lift.

An embodiment of the present invention will be described in detail with reference to FIG. Reference numeral 11 denotes a cylindrical portion, which is formed in a cylindrical shape, and has a circular arc gear portion 15 for connecting the abutment and a female screw portion 16 for connecting the abutment. The details of the circular arc gear described in JP-A No. 2012-120898 can be suitably used, but in this example, the curvature of the circular arc in the outer peripheral direction and the curvature of the circular arc in the inner peripheral direction are made the same, and the core material ( The bonding force between the fixture (fixture) and the abutment was optimized.
Reference numeral 12 denotes a radial slope, which is 25 degrees to 35 degrees, (12a) preferably 29 degrees to 31 degrees, and has a width of 2.5 mm or more with respect to the longitudinal direction of the core material.

13 is a cylindrical threaded part, and the cylindrical threaded part 13 is a spiral thread, the pitch is 1.2 to 1.6 mm, and the height is 0.3 to 0.4. An example is millimeters. A cut surface 14 is formed symmetrically with respect to the threaded portion 13 in the longitudinal direction of the core material, and has a function such as a stopper.

14 is a cut surface, which shows a state in which the surface of the threaded portion 13 is cut into a plane or an arc in the longitudinal direction. Reference numeral 15 denotes an arcuate gear portion, which fits into the arcuate gear of the abutment to prevent rotation. Reference numeral 16 denotes a female threaded portion for integrating the abutment with the fixture.

FIG. 1 shows the state of the core material without the hydroxyapatite coating layer and the oxide film (hydrothermal synthetic film) layer. The area where the hydroxyapatite coating layer is to be formed is sandblasted to form a rough surface, and the other areas, including the gingival junction, are made into a mirror polished surface, an example of which is shown in Figure 2. . 21a to 26a are sandblasted surfaces, indicating rough surface portions. 21b to 26b indicate mirror polished surfaces. 21a and 24a are first extended rough surface portions, and the rough surface portions are formed on the threaded portion 13, the radially inclined portion 12, and the cylindrical portion 11. An acicular and/or columnar hydroxyapatite coating layer is formed on the first extended rough surface portion 21a. Reference numerals 21b and 24b are first mirror-polished parts, and a mirror-polished surface is slightly formed on the upper part of the cylindrical part 11. 22a and 25a are second extended rough surface portions, and the rough surface portions are formed up to the threaded portion 13 and the radially inclined portion 12. An acicular and/or columnar hydroxyapatite coating layer is formed on the rough surface portion 23a of the threaded portion 13. Reference numerals 22b and 25b are second mirror-polishing parts, each of which has a polished surface formed by polishing the surface of the cylindrical part 11 into a mirror-like surface. 23a and 26a are rough surface portions formed on the surface of the threaded portion 13. Furthermore, an acicular and/or columnar hydroxyapatite coating layer is formed on the rough surface portions 23a and 26a. Reference numerals 23b and 26b are third mirror-polished parts, each having a mirror-polished surface. (1a) to (1c) are for implantation in areas with low bone height, and (2a) to (2c) are for implantation in areas with high bone height. This is for planting, and the length of the threaded portion differs by one pitch.
FIG. 8 shows the sandblasted surface of the fixture shown in FIG. 2, in which the hydroxyapatite coating layer extends to the radially inclined portions.
In FIG. 8, the same components as those in FIG. 2 are given the same reference numerals and explanations are omitted.
In (a), the number of pitches of the threaded portion 13a is approximately 5 as in FIG. 2, and in (b), the number of pitches of the threaded portion 13b is further set to 7.
81a and 81b are hydroxyapatite coating layers recrystallized into needle-like and columnar shapes on the sandblasted surface.
82a and 82b are hydrothermal synthetic coating parts, which are obtained by immersing a mirror-polished surface in a supersaturated aqueous solution containing phosphorus and calcium.
A supersaturated aqueous solution containing phosphorus and calcium refers to a small amount of an aqueous solution used, for example, when recrystallizing a thermally sprayed calcium phosphate coating layer into an acicular or columnar shape.
This is because an oxide film is formed on the surface of the titanium core material using calcium phosphate eluted from the coating layer after immersion, so in order to form multiple coated surfaces on the core material whose ratio of coated area changes, suitable.
In Figure 8, the core materials with different numbers of pitches can be used to accommodate changes in the amount of bone in the patient's implantation site, and are suitable for the size and depth of the patient's implantation site by selecting the covering area. In some cases, it is possible to implant a new implant without the need for GBR.

(1a) and (2a) show the state in which the hydroxyapatite coating layer has been increased in order to apply GBR to a site where there is little alveolar bone, and (1b) and (2b) show that there is little alveolar bone but ( 1a) (2a) shows a shape for applying GBR to a part where application is considered, although it is larger than that shown in (2a). FIGS. 2(1c) and 2(2c) are used for areas where the application of GBR is not considered. FIG. 4 (a) shows a state in which the fixtures shown in FIGS. 2(1b) and 2(2b) are installed. 11 is a cylindrical part, 12 is a radially inclined part, and 13 is a threaded part, which has the same shape as the core material shown in FIG. 1, and the explanation thereof will be omitted.

Diagrams for explaining the embodiment shown in FIG. 2 are shown in FIGS. 3 and 4. FIG. 3 shows a state in which an implant having the shape shown in FIGS. 2(1c) and 2(2c) is placed in the maxillary sinus with a prosthetic material due to insufficient bone volume in the maxilla. 31 is a hydrothermal coating portion, which is formed by immersing the surface of the core material in contact with the gum 3A in a supersaturated solution containing phosphoric acid and calcium and subjecting it to hydrothermal treatment. 32 is an acicular and/or columnar hydroxyapatite coating layer, and after forming a coating layer by plasma spraying on the roughened surface shown in FIGS. 2(1c) and 2c, a supersaturated layer containing phosphoric acid and calcium is applied. It is obtained by immersing the core material in an aqueous solution and subjecting it to hydrothermal treatment.

Reference numeral 33 is a bone filling material, which is made of a calcium phosphate material, crushed autologous bone, etc., and a regenerated bone portion is formed after filling. 3C is Schneider's membrane, which is placed to cover the maxilla 3B. When performing a sinus lift or socket lift, this is removed from the bone surface and a bone filling material is placed between the maxilla 3B and Schneider's membrane 3C. Shows the filled state.
In this embodiment, the diameters of the radial inclined part 12 and the cylindrical part 11 are larger than that of the threaded part 13, and even if the masticatory force is applied from above, the force is dispersed in the radial inclined part 12, so that the threaded part 13 is This prevents it from sinking and breaking through the Schneider membrane. For the core material whose volume increases upward in this way, the size of the acicular and/or columnar hydroxyapatite covering layer is selected from Figure 2 depending on the area where bone has been lost. There is also.
Then, an acicular and/or columnar hydroxyapatite coating layer is formed on the core material shown in FIG. 2, and a hydrothermal coating layer is formed on other parts by hydrothermal treatment.

FIGS. 4(a) and 4(b) show a state in which the present embodiment is applied to a region where bone is reduced after a period of time has passed after a tooth extraction, regardless of the location. The fixture shown in FIG. 4(a) has a rough surface formed up to the inclined part, as shown in FIGS. Shows the formed state. The insufficient amount of alveolar bone 4B is compensated for with a fixture that covers up to the radial inclined portion 12, and is shown filled with prosthetic material 43 as needed.

Reference numeral 41 denotes an oxide film (hydrothermal synthetic film) layer, which is obtained by immersion in a supersaturated aqueous solution containing phosphoric acid and calcium, and forms a contact surface with the gum 4A. Reference numeral 42 denotes a coating layer made of acicular and/or columnar hydroxyapatite crystals, which covers up to the radially inclined portion 12 .

43 is a prosthetic material, which is made of crushed autologous bone, calcium phosphate granules, or powder. FIG. 4 shows a prosthetic material filled at the same time as bone regeneration. The prosthetic material 43 is filled depending on the degree of alveolar bone deficiency, but may not be necessary if the acicular and/or columnar hydroxyapatite extension covering layer 44 covering the radial inclined portion 12 is sufficient to compensate. . 44 is an acicular and/or columnar hydroxyapatite extension coating layer coated on the surface of the radially inclined portion 12.

FIG. 4(b) shows a case in which a hydroxyapatite coating layer is formed up to the cylindrical portion shown in FIGS. 2(1a) and 2(2a) when the bone deficiency is greater than that in FIG. 4 ( a ). Indicated by 46 in (b). Reference numeral 45 is a lid part, which is used to compensate for the lack of a part that comes into contact with the gingival part 4A until the fixture is stabilized after the fixture is implanted because the cylindrical part 11 is embedded in the alveolar bone. It is. The lid portion 45 may not be necessary if the gingiva is thin or if the gingiva is sutured. Note that when suturing the gums, it is necessary to separately cover the abutment joint portion of the fixture with a cap.

46 is a hydroxyapatite coating layer crystallized in an acicular and/or columnar shape, and an acicular and/or columnar hydroxyapatite extension coating layer 49 is formed up to the radially inclined portion 12 and the cylindrical portion 11. Reference numeral 47 denotes an oxide film (hydrothermal synthetic film) layer formed on the gingival contact portion of the cylindrical body. Reference numeral 48 denotes a lid oxide film (hydrothermal synthetic film) layer formed on the side surface of the lid 45, and is formed by the same manufacturing method as the oxide film (hydrothermal synthetic film) layer 47. Note that the lid oxide film (hydrothermal synthetic film) layer 48 may be unnecessary if the lid is removed within a relatively short period of about one month.

49 is a needle-shaped and/or columnar hydroxyapatite extension covering layer, which is formed by extending to the radial inclined part 12 and the cylindrical part 11, and is applied when the amount of alveolar bone missing is larger. Ru. The embodiment shown in FIG. 3 shows a case where, when there is insufficient bone, the hydroxyapatite extension covering layer is selected and used depending on the amount of insufficient bone. Note that the prosthetic material used in GBR may be used if implantation according to this embodiment is insufficient.

FIG. 5 shows an example of an abutment coupled to a fixture. Components having the same configuration as those in FIG. 1 are given the same numbers, and description thereof will be omitted. 51 is an acicular and/or columnar hydroxyapatite crystallized coating layer, and 52 is an oxide film (hydrothermal synthetic film) layer, both of which are formed by the above-mentioned manufacturing method.

Reference numeral 53 denotes a male threaded portion, which is formed integrally with or separated from the abutment 57. 53a is a female threaded portion, and the fixture and abutment are coupled by the combination of the male threaded portions 53. Reference numeral 54 denotes an arcuate gear surface, and as shown in FIG. 1, eight arcuate gears are formed in a curved shape. The curvatures of the circular arc in the outer circumferential direction and the circular arc in the inner circumferential direction of the circular gear surface are configured to have the same value, so that the coupling can be strengthened. The arcuate gear surface 54 is fixed by the combination of the male threaded portion 53 and the female threaded portion 53a while being fitted into the arcuate gear recessed portion surface 54a.
In the case of a separate body, the male threaded portion 53 is inserted from above the abutment 57, as shown in FIG. 5, for example.

Reference numeral 55 denotes an inclined convex portion, which uniformly contacts the inclined recessed portion 55a on the fixture side to form a sealed state. A denture (upper structure) 56 is inserted and fixed onto the abutment 57 so as to cover it.

The threaded part 13 of the fixture 10 is embedded in the alveolar bone 5B so that the gingival part 5A, the radial inclined part 12 and the cylindrical part 11 are in contact with each other, and left standing until the bond is stabilized. After the fixture 10 is embedded and fixed in the alveolar bone 5B, the male threaded portion 53 is inserted into the abutment 57, the arc gear surface 54 and the arc gear recess surface 54a are fitted, and the inclined recess 55a and the inclined convex portion 55 are fitted. While overlapping them so as to match, the female threaded portion 53a and the male threaded portion 53 are further combined and fixed together. The shape of the denture 56 differs depending on the location of the front teeth, back teeth, etc., and may be formed by processing during treatment.
FIG. 7 shows an example of integrating a fixture and an abutment with a threaded portion.
In FIG. 7, the same components as those in FIG. 5 are given the same numbers and the explanation will be omitted.
Reference numeral 71 denotes a screw body, which is formed in a cylindrical shape, and has an operating part formed in the shape of a groove or the like for connecting a special jig such as a special driver to perform a combination operation. There is.
Reference numeral 72 denotes a male thread, in which, in addition to a general male thread, the crests of a plurality of female threads are combined with one valley of the female thread 72a, as shown in Japanese Patent Application Laid-Open No. 2003-52720. It may be a structure.
Reference numeral 72a denotes a female threaded portion, which is formed in a concave shape so as to overlap with the male threaded portion 72.
Reference numeral 73 denotes a hollow portion, which vertically passes through the abutment, into which the screw body 71 is inserted, and which has a shape that allows the male threaded portion 72 to integrate with the female threaded portion 72a on the fixture 10 side.

The present invention is applicable to the scope of dental implant treatment by combining the shape of the core material of the dental implant and the acicular and/or columnar hydroxyapatite coating layer, which allows implantation even in areas lacking bone with a small amount or no bone substitute material. can be expanded.

11 Cylindrical portion 12 Radial inclined portion 13 Threaded portion 14 Cut surface 15 Arc gear portion 16 Female threaded portion

Claims (4)

Threaded part 13 has a cylindrical shape, and a spiral groove is formed downward from the upper maximum diameter part to form a flat peak part and a flat trough part. A radial inclined part 12 that extends radially at an inclination of 25 degrees to 35 degrees with respect to the longitudinal direction of the shaft 10 and has a diameter larger than the maximum diameter part of the threaded part 13, and a large diameter part of the radial inclined part 12. It is formed of a cylindrical part 11 whose connecting side surfaces are parallel, and on the entire surface of the cylindrical part 11 that joins with the abutment 57, there are eight gears drawing an arc, and the curvature of the arc in the outer circumferential direction and the inner circumference A fixture 10 having a circular gear concave surface 54a having the same circular arc curvature in the direction, and a female threaded portion 72a formed below the inside thereof;
The entire surface of the fixture 10 that connects with the arc gear concave surface 54a has an arc gear surface 54 that is a gear that draws eight arcs and has the same curvature of the arc in the outer circumferential direction and the curvature of the arc in the inner circumferential direction. an abutment 57 formed with a hollow part 73 which is penetrated vertically;
A screw body 71 which has a male threaded portion 72a at its tip and is used to fix the abutment 57 and the fixture 10 by inserting the hollow portion 73 of the abutment 57 from above and mating with the female threaded portion 72a of the fixture 10. ,
Within the range of the threaded part 13, the radial inclined part 12, and a part of the cylindrical part 11, the crystallized needle-like and/or columnar shape is formed on the contact surface with the bone and is formed in a range according to the amount of bone. A two-piece type dental implant in which an oxide film layer 41 is formed on a portion of the fixture 10 other than the hydroxyapatite coating layer 42 and the hydroxyapatite coating layer 42 as a portion that contacts the gums. 2. The two-piece dental implant according to claim 1, wherein the oxide film layer 41 is obtained by immersing the mirror-polished surface in a supersaturated solution containing phosphoric acid and calcium. The two-piece dental implant according to claim 1, wherein the fixture (10) is made of titanium material. The two-piece method according to claim 1, wherein the acicular and/or columnar crystallized hydroxyapatite coating layer 42 has a length of 2 μm to 7 μm and is covered with crystal arrays aligned in the same direction and radial crystals. type of dental implant.

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