JPS63153071A - Living body 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 (Field of Industrial Application) The present invention relates to a biological implant used in living organisms such as humans and livestock.

(Prior Art) In the human body, livestock, etc., connection or repair prostheses are performed when bones are damaged due to fractures or other causes, or when teeth are damaged.

The biological implant used here has a core material such as a tube or rod made of metal such as titanium or cobalt-chromium-molybdenum alloy, and its surface is coated with calcium phosphate, which has high mechanical strength and is suitable for living organisms. It has been used because it has fewer negative effects.

(Problems to be Solved by the Invention) The above-mentioned prior art 1: has sufficient mechanical strength because it uses metal as the core material, but it is difficult to connect it to the bone etc. to be joined!
It tends to cause a quantitative imbalance and cause bifunctional disorders in living organisms, and if used in living organisms for a long period of time, there is a risk of damaging the bones at the joints.

In particular, when stainless steel is used as the metal and its surface is coated with calcium phosphate, the stainless steel may corrode due to contact with bones and become harmful to living organisms over many years.

(Means for Solving the Problems) The present invention has been made as a result of intensive studies to solve the problems of the conventional technology, and is based on SiC whisker-reinforced β-
The inner layer is made of sialon-based ceramic, and a calcium phosphate coating layer is provided on the surface of the inner layer.The implant is lightweight and has excellent biocompatibility without using metal.

To describe the structure of the present invention in more detail, the main components are 5 to 40% by weight of SiC rice carr, 0.5 to 25% by weight of Zr, and the balance β-sialon ceramic, and the β-sialon ceramic has the composition formula Sis - zAlzOzNm
β-sialon represented by -g (where Q (Z≦1)), and 1 to 20 weight - of Zr, Si.

A1. O, N and inevitable impurities or Y* Mg
A biological implant whose base material is a silicon carbide whisker-reinforced composite material mainly composed of a glass phase containing one or more of v(a) and rare earth elements, and a calcium phosphate coating layer is provided on the surface of the silicon carbide whisker-reinforced composite material with an alumina-based ceramic layer interposed therebetween. It is.

Regarding the β-SiAlON/base material in the present invention, if the aforementioned glass phase is less than 1% by weight, β-SiAlON cannot be sufficiently sintered and the desired density cannot be obtained. If the amount is more than 20% by weight, it is not preferable because it causes deterioration in toughness and strength.

In addition, the β-Tearon sintered body is made of Si used as a starting material,
Depending on the purity of N4 powder and the ratio of the composition, Si, N,
O, Si, ON, , Zr0N, ZrO, ZrN
, Y, O,・Si, N, , 3Y, O,-5
Al, O,,IOY, O,-9SiO,・Si,
N4.4Y, O, -8iO, -3i3N4. YSiO
,N, Mg, Sin, , Mg5iN, etc.0)
Although a small amount of the compound may be generated and present in the sintered body, it may be present within a range that does not particularly adversely affect the properties.

Further, the addition of the glass-forming compound as described above is particularly effective when employing an atmospheric pressure sintering method or a gas pressure sintering method.

As mentioned above, the z value of β-sialo/composition is set to 0 (
The reason for setting Z≦1 is that when z>1, mechanical strength and toughness decrease, making it impossible to satisfy necessary mechanical properties. On the other hand, SiC whiskers are added in an amount of ~40% by weight, but if it is less than 5% by weight, no improvement in the toughness of the ceramic material is observed; The above range is preferable, and more preferably 1.
0 to 30% by weight,
4 = Ayu 1 [So 4 Ki] Most preferably 15 to 25% by weight.

Note that the SiC whiskers used in the present invention have an average diameter of 0.2 to 11j! 111 average length 5-50 μ chips, aspect ratio 5-5000, A11 Ca, *
MgeNl, Fe, Mn, Co, Cr
Kabuon impurities such as S10. Content is 1.0 weight -
In order to obtain a highly tough dense body, it is preferable to use the following whisker-like crystals that have fewer constrictions, branches, and surface defects.

In addition, ZrO is added in an amount of 2 to 25% by weight, but ZrQ is added.

is dissolved in a small amount in the glass phase to improve the wettability of the glass phase and SiC whiskers at the interface, enabling a stronger bond, thereby allowing the SiC whiskers to fully demonstrate their original properties. and improves toughness. Therefore, the amount of ZrO added and the type of glass-forming compound added as a sintering aid for Sialon (for example, Y
The final crystal form of ZrO (ZrO, present in the sintered body) differs depending on the amount added (ZrO, MgO, etc.) and exists in the sintered body as monoclinic, tetragonal, cubic, or a coexistence of these. However, if the amount of ZRO is less than 5% by weight, the effect is not sufficient. Undesirable.

Alumina ceramic has a coefficient of thermal expansion between β-sialon and calcium phosphate, and is used to relieve internal stress due to the difference in thermal expansion between the two. α-alumina, which has a stable crystal layer, is preferable.

Calcium phosphate (mainly calcium phosphate with a ca/P atomic ratio of 1.4 to 1.75 disclosed in JP-A No. 55-56052 U "Production method of high-strength calcium phosphate sintered body") A particularly strong product in which a calcium phosphate frit having a Ca/P atomic ratio of 0.2 to 0.75 is added to the powder and mixed with 0.5 to 15% by weight of the calcium phosphate component after firing, and then melted. or sintered calcium phosphate containing 0.5 to 15% by weight of alkali metal, zinc and/or alkaline earth metal oxide-phosphoric acid frit (Japanese Unexamined Patent Publication No. 55-140756 "High A sintered product obtained by sintering a powder mainly composed of calcium phosphate and a calcium phosphate frit disclosed in JP-A No. 55-80771 "High-strength calcium phosphate sintered body") It is known that the aggregate contains 3 to 23 of Y, O, as a reinforcing agent.

However, the calcium phosphate defined in the present invention is not limited to this, and includes everything from glass and crystal bodies containing a large amount of calcium phosphate to what is commonly called 7-batite ceramic.

(Example) The following will be explained with reference to the drawings. The figure shows an example of a biological implant, and 1 is a dental implant of the present invention, which has a tooth root 11 at its lower part. The tooth root portion 11 consists of a β-sialon grave ceramic 5 at the center, an alumina-based ceramic layer 2 and a calcium phosphate coating layer 3 thereon.

The method for coating calcium phosphate is as described in Test Example 1 or 2, and a dental implant coated with calcium phosphate can be prepared.

When producing the biological implant of the present invention, the surface of lucium has pores of 16 to 400 microns, and has an even better affinity with bones. When implanting this in the jawbone, the gingival mucosa A of the living body is incised and peeled off, and a screw hole that matches the shape of the implant is drilled in the jawbone B. Implant by inserting. A crown T is placed at the tip of the implant implanted in this way.
are adhered with adhesive 4. Implants implanted in this way have an extremely high affinity with the jawbone due to the calcium phosphate on the surface, and the calcium phosphate is gradually replaced by the bone.Also, because the surface is uneven, the bone and ceramic have a large area. It is preferable because it has strong adhesion and can withstand long-term use, but the purpose can be achieved even if it has a dense surface.

In this embodiment, the surface of the ceramic is a threaded part, but the present invention is not limited to this, and may have vertical grooves, horizontal grooves, corrugations, etc. After the ceramic is vapor-deposited, ceramic powder, glass powder, etc. can be formed by flame spraying, etc. Even if the surface is made into a porous layer by appropriately adjusting the particle size and flame temperature, the bone and ceramic surface will fit tightly together.

The present invention is not limited to this embodiment, and by using a prosthetic member for other parts of the bone, the shape of which can be freely designed, it is possible to exhibit excellent strength and biocompatibility.

Next, as described below, test pieces of the present invention and a comparative example were made and their characteristics were evaluated.

Test Example 1: Si, N, powder with an α rate of 90 cm and an average particle size of 0.6 μm, α-Al, O, powder with an average particle size of 1 μm, SiC whisker (SC-9 manufactured by ARCO Chemical Co., Ltd.) and the average particle Monoclinic ZrO having a diameter of 0.3 mm was blended in the proportions shown in Table 1, uniformly dispersed and mixed in ethanol for 4 hours, then dried and granulated to obtain a base powder.

Next, this base powder was hot pressed in a graphite mold at a pressure of 200#/3'' for 60 minutes at different sintering temperatures shown in the table to obtain a densely sintered sintered body (substrate). .

The obtained sintered body (substrate) was polished to a size of 4 x 3 x 40 mm, and then the flexural strength and fracture toughness values were measured using JIS-R1601ζ and the indentation microfractear method. Through chemical analysis and carbon quantification, it was confirmed that the composition of the sintered body remained almost the same. Further, the binary values of β-sialon were determined from the lattice constant of β-sialon by X-ray diffraction.

The results obtained are shown in Table 1.

Next, threads with a pitch of 1H were cut in the base 15 layers of the 2.5WφX 25ML substrate, and a 10μ α-A
m, 0. After providing the coating layer 2, it was immersed in a calcium phosphate slurry, dried, and fired at 700° C. in the atmosphere to produce a dental implant whose surface was coated with calcium phosphate.

Calcium phosphate slurry is, for example, qacos20 # and P
, 0.14# and calcined at 1600°C for 2 hours to form a semi-molten state to form a mixture of calcium phosphate glass and crystals (Ca/P atomic ratio approximately 1), which is trommeled to 5μ or less. After the particles were broken down to 40%, they were poured into water in which 1% of methylcellulose was dissolved and stirred to form a slurry of calcium phosphate.

The characteristics of the coated product in this case are also shown in Table 1 (Table 1). The structure was found to have excellent toughness, and the coated product with a calcium phosphate coating on the outside was found to have excellent properties not only in biocompatibility but also in bending strength.

Test Example 2: Y, O,, MgO, CaO, D with an average particle size of 2μ or less
y, O.

After obtaining a base powder in the proportions shown in Table 2 in the same manner as in Test Example 1 except that Zr, Si, AI, 0, N and unavoidable impurities were added as glass-forming compounds, A dense sintered body (substrate) was obtained by hot pressing for 60 minutes at 200 m/i2. The mechanical properties of the obtained sintered body (substrate) were evaluated in the same manner as in Test Example 1, and the results are shown in Table 2.

From this result, we found that the glass phase, which is mainly composed of Zr, Si, Am, O, N, unavoidable impurities, and one or more of added Y, Mg, Ca, and rare earth elements, is
0! It was found that the β-sialon group composite sintered body containing 1% of j was a sintered body having excellent strength and toughness.

Next: A dental implant was produced in the same manner as in Test Example 1, and its coating properties are shown in Table 2. The properties of this coated product were found to be excellent in biocompatibility and bending strength.

(Effects of the Invention) As described above, the present invention is lighter than conventional metal-calcium phosphate-based biological implants, has good biocompatibility when installed, causes almost no abnormal sensation, and connects with time. There are some materials that have various advantages such as being integrated with bone and maintaining strength similar to that of metal.

[Brief explanation of the drawing]

The figure is a longitudinal cross-sectional view of the implanted example (dental implant) of the present invention. A... Gingival mucosa, B... Jawbone, T... Crown, 1.
...Dental implant, 2...Ceramic coating layer, 3
... Calcium phosphate coating layer, 4... Adhesive, 5...
-β-sialon-based ceramic, 11... tooth root. Agent Patent Attorney Moritake Takeuchi

Claims (1)

[Claims] SiC whisker 5-40% by weight, ZrO_25-25
weight%, the balance is mainly composed of β-sialon ceramic, and the β-sialon ceramic has the composition formula Si_6_
−_zAl_zO_zN_8_-_z (However, 0<z≦1
) and 1 to 20% by weight of Z
r, Si, Al, O, N and inevitable impurities or Y,
A biological implant characterized in that a calcium phosphate coating layer is provided on a silicon carbide whisker-reinforced composite material mainly composed of a glass phase containing one or more of Mg, Ca, and rare earth elements with an alumina-based ceramic layer interposed therebetween.