JPS62167559A - Dental implant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an improvement in a dental implant that serves as a base for mounting an artificial tooth crown.

(Background of the Invention) Recently, attempts have been made to implant artificial teeth as one of the treatments for severe central teeth and alveolar pyorrhea. One type of such artificial teeth is known as a separate type, which is divided into an artificial crown and a dental implant that serves as a base for mounting the crown. These implants are implanted into the alveolar bone and were originally made of bioinert materials such as metal. The shape is cylindrical, cannonball, inverted cone, or inverted truncated cone in consideration of ease of manufacture, ease of implantation surgery, and even distribution of occlusal pressure.

By the way, when an implant made of bioinert material is to be firmly connected to bone, the method originally considered was screwing.

However, this method places large stress locally on the bone,
As a result, there was a risk of bone resorption (disappearance) and inflammation, and there was also a risk of bacterial infection due to the presence of microscopic gaps at the interface between the implant and the bone.

In response, bioactive glasses (including fully or partially crystallized glass-ceramics) have been developed that chemically bond directly to living bone. This glass reacts in vivo when it comes into contact with body fluids.

Specifically, ions such as Na, Ca, P, B, and 8T, which are the constituent atoms of bioactive glass, are dissolved out from the surface of the bioactive glass, forming pores on the surface, and the bioactive glass P, Ca ions eluted from the glass and <P, Ca valley ions due to the action of living remains are deposited and crystallized to form hydroxyapatite, which is an inorganic component of bone. This creates a direct chemical bond between the bone and the glass.

This description is given in Reference J, 13iomed, Mater.
Res, Symp.

1VIkL2 (Part 1) 117-141(1
971) K details.

A dental implant using this bioactive glass was developed (Japanese Patent Application Laid-open No. 145394/1983,
No. 1-8970, JP-A No. 57-3739), and is currently undergoing clinical trials.

These types of implants can be broadly divided into two types: the buried type, in which the implant is completely buried in the bone and the upper surface is covered by the gingiva, and the gingival type, in which the implant protrudes from the entire upper bone and is exposed without being covered by the gingiva. Divided into penetration types. In any case, after this, the artificial tooth crown (superstructure) is completely attached after confirming that it has been completely bonded by leaving it for up to three months to chemically bond with the bone.

FIG. 2 shows a full perspective view of an example of the gingival penetrating type.

FIG. 3 is a vertical sectional view of the implant shown in FIG. 2, and FIG. 4 is a conceptual diagram showing how the implant is implanted in the mandible bone and a superstructure is attached.

Generally, glass has low tensile strength, so in implants using bioactive glass, the lower body of the post core 5 is fitted into this second hole and bonded with adhesive, and the artificial tooth crown is attached to the upper body of the post core 5. Install 6. In the case of a transgingival type implant, as shown in FIG. 4, most of the implant is implanted in the bone 7, and the upper part is exposed from the gum 8.

Therefore, the gums 8 are in contact with the bioactive glass 2.

Another type of implant was in contact with a metal core l. Therefore, although the detailed cause is not known, with conventional implants, inflammation may occur in the gums 8 two weeks to two months after implantation, which has been a problem.

(Objective of the Invention) The object of the present invention is to provide a transgingival implant using bioactive glass that is less likely to cause inflammation in the gums after implantation. It is on offer.

(Summary of the Invention) Therefore, in the present invention, the surface in contact with the gums (portion A shown by crosshatching in FIG. 2) is made of a bioinert material 3, and the surface in contact with the bone (B in FIG. 2) k To provide a gingival penetrating implant made of bioactive glass 2.

As the bioinert material 3, for example, apatite sintered body,
Sapphire (alumina single crystal), alumina (polycrystalline),
Examples include metal and ceramics. Among these, apatite sintered bodies are preferred. The apatite sintered body does not easily cause inflammation, and even if it comes into contact with the jawbone, it has an affinity for the jawbone. This is preferable because there is no problem with remaining power even if it does not match exactly with the top, and there is also the advantage that the implantation technique can be rough.

Such apatite sintered body has the same color composition of inorganic components as hydroxyapatite: Ca, (PO4
) = (OH) = or fluoroapatite whose OH group is substituted with fluorine, or sintering aids such as various metal oxides and glass to these apatites.

It is made of bioactive glass mixed with gold and sintered, and this itself is already known.

On the other hand, a bioactive glass 2μ, for example, has the following composition.

S i 0135~60mo1% B! Qs O~15mo1%Na
g O10~30mo1% cao 5~40mo1%TiO"
O~10mo1%P Oa

O-15mol %L 0
0-20mol %L It OO
~10mol% Mg0 0~5mol%A11yO
s 10 Zr Ox +Nbt Os O~8mo
1%: [, at Qs +Ta-0* +Y-0-0~
8mo1%p, 0-20-2O
The metal core 1 is made of titanium, stainless steel, or other iron-based austenitic alloy.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

(Example 1) FIG. 1 is a vertical cross-sectional view of the implant of this example,
is an inverted truncated cone-shaped iron-based austenitic alloy core l;
Bioactive glass 2 and apatite sintered body 3 covering this
Consisting of

The metal core 1 has a height of 15 mm and a top diameter of 3.6 mm.
, maximum diameter is 4mm, bottom diameter is 2mm
．． It has a cylindrical hole 4 with a diameter of 2.8 mm and a depth of 12 marks at the top. Hole 4 is for fitting the boss core.

The thickness of both the glass 2 and the apatite sintered body 3 is approximately 0.2
mm, and the apatite sintered body 3 has a surface A in contact with the gums.
and occupies the upper part.

(Example 2) The implant of this example is shown in FIGS. 5 and 6, and includes a substantially cylindrical metal core 1, and a surface that contacts the gums and a surface above the outer surface of the metal core 1. It consists of a covering apatite composite 3, a bioactive glass 2 covering the surface that comes into contact with the bone, and a base glass layer 9.

The core is made of 1hNi-Cr gold alloy (trade name "Samarium" manufactured by Sankin Kogyo Co., Ltd.), and the height is 15n1 [11
, the maximum diameter is 4 mm, and the top diameter is 3.6 mm.

The upper part of the core body has an upper diameter of 2.8 mm, a depth of 12 mm, and a lower diameter of 2 mm for fitting the post core.
There is a substantially cylindrical hole 4. Further, a pair of grooves 10 are formed on the upper surface of the core body 1, and a tool such as a screwdriver can be engaged therein to fully rotate the implant.

Apatite composite 3 has a thickness of 0.2 and a core 1.
It covers the 5th and 6th positions from the top surface.

Compositionally, the apatite composite 3 is a mixed sintered body of bioactive glass powder and hydroxyapatite or fluoroapatite powder, and preferably the bioactive glass component accounts for 40 to 70% by weight. A type in which the two react during sintering may also be used. The composition of such types of bioactive glasses is e.g. SiO,46,1
mol%, Na, 022.0 mol%, Ca0 14.0 mol%, CaF, 15.3 mol%, P-Og 2.6 mol%, and hydroxyapatite and 400 to 50 mol%.
The reaction takes place at 0°C to convert hydroxyapatite into fluoroapatite. Fluoroapatite has a sintering temperature (
It is stable even at temperatures of 700 to 1200°C) and hardly changes into oxidized apatite.

The bioactive glass 2 occupies the bone contacting surface of the implant and has a thickness of 0.25 mm. The bioactive glass 2 chemically bonds to the jawbone two weeks to two months after implantation. The bonding strength between an apatite sintered body (hydroxyapatite sintered body, fluoroapatite sintered body, apatite composite, etc.) and bone is high. This glass 2 is provided with four protrusions 2a.
Prevent the implant from falling out of the bone immediately after implantation in a.

The bioactive glass 2 may be eroded by body fluids in some cases, and if the erosion progresses to the surface of the core 1, the overall bond between the bioactive glass 2 and the core 1 will be adversely affected. Therefore, in this embodiment, a base glass layer 9 (thickness 0.25
mm) i is provided. The base glass layer 9 has no or almost no bioactivity.

(Effects of the Invention) In the present invention, in a gingival-penetrating implant using bioactive glass, the surface that contacts the gingiva is made of apatite sintered body, so the risk of gingival inflammation is minimized.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of an implant according to Example 1 of the present invention. FIG. 2 is a perspective view of a conventional transgingival implant. 3 is a vertical cross-sectional view of the implant of FIG. 2; FIG. FIG. 4 is a conceptual diagram showing how the implant shown in FIG. 2 is implanted in the jawbone. FIG. 5 is a top view of the implant of Example 2. FIG. 6 is a vertical cross-sectional view of the fifth implant. [Explanation of symbols of main parts] 1...Metal core, 2...Bioactive glass, A...Gingival contact surface, 3... A bioinert material or an apatite sintered body as an example thereof or an apatite composite as an example thereof, 4
...hole, 7...bone, carcass...gums.

Claims (1)

[Claims] A transgingival dental implant characterized by having a surface in contact with the gums made of bioinert material and a surface in contact with bone made of bioactive glass.