JP2553396Y2 - Artificial root - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial dental root used in a dental treatment department to reconstruct the function of a natural tooth lost due to aging, disaster or illness.

[0002]

2. Description of the Related Art Conventionally used artificial roots are made of a material such as cobalt / chromium alloy, pure titanium, titanium alloy, or ceramic alone or in combination, and form a channel-shaped hole in the jaw bone. And in it, a rod,
Alternatively, an embedding portion of a plate-shaped artificial tooth root is buried, a rod-shaped post portion is protruded out of the bone through the gingiva, and an upper structure is attached to the post portion.

[0003] In such an artificial tooth root, after implanting, new bone grows and forms, and until the bone is firmly fixed with the jaw bone,
Stimulation of the post due to tongue pressure.Stimulation of the artificial root and extension to the lower part of the gingival epithelium due to such stimulation may result in funnel-shaped bone resorption around the post and infection of the jaw bone tissue. . In order to solve this problem, in addition to the firm fixation to the jaw bone tissue, an early sealing action at the abutment portion with the gingival portion must be realized. Therefore, as shown in FIG. 5, a hard tissue bonding layer 22 made of apatite is provided around a screw portion 21 of a portion of the base 20 made of titanium or a titanium alloy that comes into contact with the jaw bone, and a gingival contact portion 23 that comes into contact with the gingiva. An artificial tooth root 10 having a post 24 on which an artificial crown is to be placed has been developed and used clinically, in which a tubular member 30 made of a ceramic material, particularly single crystal alumina, is inserted.

[0004]

2. Description of the Related Art The above-mentioned artificial tooth root 10 does not necessarily prevent the above-mentioned cases such as the funnel-shaped bone resorption around the post portion and the infection of the jaw bone tissue. In the artificial tooth root 10, a ceramic tubular member 30 made with high accuracy must be used. This is complicated in manufacturing the artificial tooth root 10. A slight gap was created between the two, and there was a risk that infection to the jaw bone tissue would occur through the gap.

[0005]

In order to solve the above-mentioned problems, the present invention provides a biodegradable base material containing at least one of chitin, chitin derivative, collagen and collagen derivative at the contact portion with the jaw bone. The present invention provides an artificial root having a hard tissue bonding layer formed thereon and a soft tissue bonding layer formed by cross-linking the biodegradable base material in a contact portion with the gingiva.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partial sectional view of an artificial tooth root 1 according to the present invention.
Is a substrate. The base 2 is made of a ceramic material such as single crystal alumina, or a metal material such as a cobalt / chromium alloy, pure titanium or a titanium alloy. As shown in the schematic diagram of FIG. This is the part 2a. A hard tissue bonding layer 3a made of a biodegradable base material containing at least one of chitin, collagen, a chitin derivative and a collagen derivative is adhered to the surface of the screw portion 2a. Part 2b
The soft tissue bonding layer 3b made of the crosslinked biodegradable base material is adhered to the gingival C which is a soft tissue. The upper part of the artificial root 1 is a post 2c for setting the artificial crown H.

As a method for forming the soft tissue bonding layer 3b, a chitin derivative such as chitosan, carboxymethylquine or phosphorylated chitin, a collagen derivative such as atelocollagen or gelatin, and a powder containing at least one of chitin and collagen are used. With an acid solvent such as distilled water, hydrochloric acid or acetic acid, concentration of 1 wt% to 20 wt% to obtain appropriate viscosity
And dissolve this paste in the gingival abutment portion 1b.
And then air dry. This step is repeated several times to form an adhered layer having an average layer thickness of 50 to 300 μm. Next, a cross-linking treatment is performed for the purpose of delaying the in vivo decomposition rate of the hard tissue bonding layer that comes into contact with the gingiva C. As the crosslinking method, there are two methods of crosslinking with a drug such as glutaraldehyde and vacuum thermal crosslinking. However, the method using a drug may show toxicity at 140 to 180 ° C.
At a temperature of 2 to 30 hours to perform a vacuum cross-linking to form a soft tissue bonding layer 3b.

The method for forming the hard tissue bonding layer 3a is as follows. After forming the soft tissue bonding layer 3b, a chitin derivative such as chitosan, carboxylmethylquine or phosphorylated chitin, a collagen derivative such as atelocollagen or gelatin, chitin Powder containing at least one of collagen and collagen is dissolved in an acid solvent such as distilled water, hydrochloric acid or acetic acid so as to obtain an appropriate viscosity so as to have a concentration of 1 wt% to 20 wt%. After applying to 2a, air dry. This step is repeated several times to form a hard tissue bonding layer 3a having an average thickness of 50 to 300 μm.

The average thickness of the hard tissue bonding layer 3a is 50
If the thickness is smaller than μm, a part of the surface of the substrate 1 may be exposed. On the other hand, if the thickness is larger than 300 μm, the adhered layer may be broken by the shrinkage during the air drying.

Carboxymethyl chitin (hereinafter abbreviated as CM chitin), which is a derivative of chitin, and gelatin, which is a derivative of collagen, are each dissolved in acetic acid and air-dried, crosslinked at each temperature, and decomposed in a simulated body fluid. The properties were examined over time. The results are shown in FIGS.

As can be seen from both figures, CM chitin and gelatin both maintained their shapes without being decomposed for more than two months in the case of vacuum thermal crosslinking at a temperature of 140 ° to 180 °. In a similar experiment using chitin and collagen, almost the same results were found.

The hard tissue bonding layer 3a and the soft tissue bonding layer 3
Since b is composed of at least one kind of biodegradable base material of chitin, chitin derivative, collagen and collagen derivative, it is extremely excellent in inducing proliferation and production of new bone at an early stage and sealing action with soft tissue, and has been subjected to crosslinking treatment. Since the soft tissue bonding layer 3b has a low decomposition rate in vivo, the support at the initial gingival portion is stable. Therefore, it is possible to prevent the gingival epithelium from lowering until the initial fixation of the artificial root is obtained. On the other hand, the hard tissue bonding layer 3a to be implanted in the jaw bone B is preferably not subjected to crosslinking treatment since it is preferable to absorb or decompose into the living body after the growth of new bone at an early stage.

The artificial tooth root 1 of the present invention may be of a bridge type.

EXAMPLE 1 A paste prepared by mixing 5 g of CM chitin and 1 g of gelatin in 100 ml of distilled water was applied to the gingival contact portion 2b above the screw portion 2a of the substrate 2 made of single crystal alumina using a brush. And air-dried. By repeating this several times, 1
Vacuum crosslinking was performed at 60 ° C. for 24 hours to form a soft tissue bonding layer 3b having a thickness of 300 μm. Subsequently, a paste in which 5 g of CM chitin and 1 g of gelatin were mixed with 100 ml of distilled water was applied to the surface of the screw portion 2a of the substrate 1 using a brush and air-dried. By repeating this several times, the soft tissue bonding layer 3b
A hard tissue bonding layer 3a having the same thickness as that of Example 1 was formed around the screw portion 2a, and three artificial dental roots 1 were produced.

The three artificial tooth roots 1 of the present invention thus produced and a hard tissue bonding layer 22 made of apatite are provided around a screw portion 21 of a base 20 made of titanium or a titanium alloy as shown in FIG. A tubular member 30 made of single-crystal alumina is inserted around the gingival contact portion 23 that contacts the gingiva.
Three artificial tooth roots 10 of 4 were implanted in the jawbone B of a mongrel dog as a control group.
The animals were sacrificed one day and one month later, and the area around the artificial tooth root 1 of the present invention and the artificial tooth root 10 serving as a control was searched over time.

The histopathological search for the gingival part was as follows. In the case of the artificial tooth root 1 of the present invention, inflammatory cell infiltration was observed on the 7th day, but disappeared on the 14th day and thereafter. Even after one month, no decomposition was observed in the soft tissue bonding layer 3b containing CM chitin and gelatin, and it was confirmed that the connective tissue was in close contact with the surface of the artificial dental root 1 in the connective tissue portion under the gingiva. did it.

On the other hand, in the control group, it was confirmed that the connective tissue was in contact with the surface of the artificial tooth root, but the connection was considerably less sparse than in the case of the above-described artificial tooth root of the present invention.

The histopathological search at the gingival part was as follows. In the case of the artificial tooth root 1 of the present invention, inflammatory cell infiltration was observed on the 7th day, but disappeared on the 14th day and thereafter. On the 14th day, it was confirmed that the formation of new bone was started on the hard tissue bonding layer 3a containing CM chitin and gelatin. On the 1st month, the hard tissue bonding layer 3a was absorbed by the living body. It was confirmed that the bones of increased maturity were in contact with the threads of the screw portion 2a.

On the other hand, new bone formation was observed in the control group, but a part of the control group was surrounded by loose connective tissue.

Example 2 A paste of a hydrochloric acid solvent containing 20% by weight of chitosan was applied to the surface of a gingival abutment portion 2b adjacent to a screw portion 2a of a substrate 2 made of a titanium alloy using a brush and air-dried. . This was repeated several times, and the substrate 1 was heated at 140 ° C. for 24 hours.
200 μm thick hard tissue bonding layer 3 with vacuum cross-linking for 3 hours
b was formed around the gingival contact portion 2b of the base 2.
Subsequently, the paste containing 20 wt% of chitosan was applied to the surface of the screw portion 2a of the base 2 using a brush and air-dried. This operation was repeated several times to form a hard tissue bonding layer 3a having the same thickness as the soft tissue bonding layer 3b around the screw portion 2a, thereby producing three artificial dental roots 1.

A paste made of an acetic acid solvent containing 15% by weight of collagen was applied to the surface of the gingival contact portion 2b adjacent to the screw portion 2a of the base 2 made of pure titanium using a brush and air-dried. This was repeated several times, and the substrate 2 was vacuum-crosslinked at 140 ° C. for 24 hours to obtain a thickness of 150 μm.
m of the hard tissue joining layer 3b of the base 2
Around. Subsequently, the screw portion 2a of the base 2
The paste containing 20% by weight of gelatin was applied to the surface of using a brush and air-dried. This operation was repeated several times to form a hard tissue bonding layer 3a having the same thickness as the soft tissue bonding layer 3b around the screw portion 2a, thereby producing three artificial dental roots 1.

The two types of artificial dental roots 1 prepared as described above were implanted in the jawbone B of a mongrel dog, sacrificed after 7 days, 14 days and 1 month, and histopathologically evaluated around the artificial dental root 1 with time. Search was performed.

The histopathological search for the gingival part was as follows. In the artificial dental implant 1 of the present invention, inflammatory cell infiltration was observed on the 7th day, but disappeared on the 14th day and thereafter. Even after one month, no degradation was observed in the collagen-containing soft tissue bonding layer 3b and the chitosan-containing soft tissue bonding layer 3b. In the connective tissue portion under and above the gingiva, the connective tissue was in close contact with the surface of the artificial dental root 1. Was confirmed.

The histopathological search for the gingival part was as follows. In the artificial dental implant 1 of the present invention, inflammatory cell infiltration was observed on the 7th day, but disappeared on the 14th day and thereafter. On the 14th day, it was confirmed that the formation of new bone was started on the hard tissue bonding layer 3a containing collagen and the hard tissue bonding layer 3a containing chitosan. Both of the hard tissue bonding layers 2a were absorbed by the living body, and it was confirmed that the bones having increased maturity were in contact with the threads of the screw portion 2a.

As described above, the results of the above-described animal experiment are exactly the same as those in Example 1, and the artificial tooth root 1 of the present invention was obtained.
Prevents the lowering of the gingival epithelium and significantly promotes the growth and production of new bone.

[0026]

[Effects of the Invention] As described above, the artificial tooth root of the present invention has an excellent sealing action with the gingiva and an ability to induce the growth and generation of new bone, thereby preventing the gingival epithelium from descending and realizing a secure and strong fixation with the jaw bone. I do. In addition, it is a safe artificial tooth root that is not complicated to produce and does not generate gaps that cause infection and the like.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing an artificial tooth root of the present invention.

FIG. 2 is a schematic diagram for explaining a state in which the artificial tooth root shown in FIG.

FIG. 3 is a graph showing the degree of swelling of carboxylmytilchitin.

FIG. 4 is a graph showing the degree of swelling of gelatin.

FIG. 5 is a partial sectional view showing a conventional artificial tooth root.

[Explanation of symbols]

 B: Jaw bone C: Gingiva H: Artificial crown 1: Artificial crown 2: Base 2a: Screw part 2b: Gum contact part 3a: Hard tissue bonding layer 3b: Soft tissue bonding layer

Claims (1)

(57) [Scope of request for utility model registration] 1. A hard tissue bonding layer made of a biodegradable base material containing at least one of chitin, a chitin derivative, collagen and a collagen derivative is applied to a contact portion with the jaw bone, and the contact with the gingiva is performed. An artificial tooth root having a soft tissue bonding layer formed by cross-linking the biodegradable substrate on a portion.