JPS62268561A - Composite material for living body - 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] [Industrial application fields] The present invention relates to composite materials for living organisms.

[Prior Art] In recent years, artificial materials such as artificial tooth roots and artificial bones have been used as substitute materials for the restoration of tooth roots and bones. As such artificial materials, corrosion-resistant and high-strength alloys such as nickel-chromium alloys and nickel-titanium alloys, and polymeric materials such as polyvinyl alcohol and high-density polyethylene have been used.

However, these materials tend to elute metal ions and monomers into living organisms when used for a long period of time, and also have poor biocompatibility.

On the other hand, some ceramic materials have excellent biocompatibility. Examples of such ceramic materials that have been put to practical use include single crystal and polycrystalline alumina, and single crystal alumina is particularly characterized by its high strength.

However, since alumina ceramics do not form chemical bonds with bones, in order to fix them in vivo, it is necessary to physically fix them to the bones by cutting screws or drilling holes in the 7-lumina ceramics themselves. . In this case, if the shape of the material is inappropriate, stress concentration may occur in the bone or part of the material, resulting in fractures, bone resorption, and loosening or falling off.

Ceramics are being used for logging to solve the above-mentioned problems by chemically bonding bone and material.

Typical examples of this type of ceramics include sintered bodies of hydroxyapatite, Na20-CaO-P20s-Si02-based bioglass (Japanese Patent Application Laid-Open No. 50-21015), and N
a20- to 20-MgO-CaO-P20s-S i
Crystallized glass in which apatite crystals or wittrokite crystals are precipitated from 02 series and MgO-CaO-P2O3-9i02 series glasses (JP-A-50-21015, JP-A-57-191252, JP-A-80-137853)
, JP-A-80-8985), etc. are known.

However, hydroxyapatite sintered bodies, bioglass,
The bending strength of crystallized glass with precipitated apatite crystals or witrockite crystals is approximately 2000 kg/
cm' or less, has low mechanical strength and can be used as a bone substitute material.
The drawback is that it can only be used in areas where little force is applied.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the drawback that conventional biomaterials that directly connect with bones have insufficient strength as structural materials in the living body, and to This provides a new material that is strong and can chemically bond to bone.

[Means for Solving the Problems] The present invention provides 130 to 99% by volume of crystallized glass containing whitlockite crystals or apatite crystals as main crystals.
and a reinforcing material 1 to 70% by volume, and the crystallized glass is essentially CaO 30 to 50 P2O340 to 55 Al2O28 to 15 MgO 0 to 5 Si02 0 to 10 B2O3 0 to 15 Additional components 0 in weight % The object of the present invention is to provide a composite material for biological use consisting of ~10.

In the present invention, the reinforcing material is added to the crystallized glass in a volume percentage of 1 to 1% by volume.
The reason for this limitation is as follows.

If the reinforcing material content is less than 1%, sufficient improvement in mechanical strength cannot be obtained, and if it exceeds 70%, it becomes difficult to obtain a material with a dense Ml weave, resulting in a decrease in mechanical strength. The reinforcing material is more preferably in the range of 10 to 60% of the above range.

Such reinforcing materials are heat resistant and have high tensile strength; specifically, zirconia, alumina,
SiC, Si3N4. Examples include carbon and potassium titanate. These reinforcements are used as particles, fibers and whiskers.

The crystallized glass in the present invention is apatite [Ca+o (PO4)6・(OH)2] which has excellent affinity with living organisms.
, witrockite [3(CaO, MgO1P205
] is the main crystal.

Such crystallized glass is produced by crystallizing glass having the following composition.

Essentially in weight % CaO　　　　　30~50 P20540-55 A 1203 8-15 MgO0~5 Si02 0~10 B2O3 0~15 Additional ingredients 0-10 A glass having a composition consisting of: is manufactured by a melting method.

The reason for the limited composition of this glass will be explained.

If CaO is less than 30%, it is not preferable because there are few apatite and witrockite crystals precipitated from the glass.
Moreover, if it exceeds 50%, the tendency of glass to devitrify is significant and it is difficult to form glass.

If 5102 is 10% or more, the melting temperature of the glass becomes too high, making it difficult to manufacture the glass.

When MgO exceeds 5%, the tendency of the glass to devitrify increases, making it difficult to mold the glass.

If P2O5 is less than 40% or more than 55%, the glass tends to devitrify, which is not preferable.

Although MgO, SiO2, and B2O3 are not essential components, adding them can facilitate vitrification.

However, addition of 5% or more of MgO, 10% or more of 5i02, and 15% or more of B2O3 is not preferable because the amount of precipitation of witzkite crystals and apatite crystals decreases and the tendency to devitrify increases.

If the Al2O content is less than 38%, vitrification becomes difficult.

If it is more than 15%, it is not preferable because the amount of witrockite crystals and apatite crystals precipitated from the glass decreases.

In addition to the above components, Zr02, TiO2, Ta205
, CaF2, Shi120, Na20, and lhO, one or more of them may be added in an amount of 10% or less. However, if the total amount of these components exceeds 10%, the amount of apatite crystals and witlockite crystals produced will decrease, which is not preferable.

Among the above additives, CaF2, L120, Na20, K2
If O is added in an amount of 5% or more, the tendency of the glass to devitrify becomes significant, so the amount of these oxides or fluorides added is preferably 5% or less.

These glasses are made by heating the prepared raw materials at 1400 to 1600°.
It can be produced by heating for C11 to 5 hours.

The composite material in the present invention can be manufactured, for example, as follows. The glass produced as described above is formed into flakes and crushed to obtain glass powder. Next, the glass powder and reinforcing material are mixed in a predetermined ratio and pressure-molded. Next, this is heated to a temperature slightly higher than the softening point of the glass and held for 1 hour or more to sinter it and precipitate apatite and witrockite crystals on the glass.

[Example 1] Glasses corresponding to the compositions shown in Table 1 were mixed with oxides, carbonates,
It was prepared using raw materials such as phosphate fluoride and melted in a platinum crucible at 1400 to 1600°C for 3 hours.

The molten glass was formed into a thin glass plate using a roll forming machine, and then placed in a bot mill and pulverized to a particle size passing 350 mesh. The glass powder is heated at a heating rate of 5°C/min from room temperature to a constant temperature in the range of 850 to 1050°C while applying a pressure of 350kg/cm', and held at this temperature for 1 hour, Sintering and crystallization were performed. After that, it was cooled to room temperature in the furnace. When the fractured surface of this crystallized glass was observed using an SEM, it was found that each had a dense structure with almost no pores.

As a result of pulverizing these samples and identifying the precipitated crystals by xvi diffraction, whitlockite crystals were observed in all samples, and in addition to these crystals, crystals such as anorthite and pearlinite were also precipitated. It was done. Table 1
The types of crystals precipitated in each sample are also shown. Also, for some samples, #2000 Si
The bending strength was measured using a 3×3×25m+n square column whose surface was polished with C abrasive grains. The results are also listed in the table. The crystallized glass made of only glass powder thus obtained has a bending strength of 1500 to 2200 kg/cm'.

Next, a reinforcing material was added to the glass sample No. 1.4 in the same table, and a pressure crystallization treatment was performed in the manner described above to obtain a composite material. Next, the flexural strength of these composite materials was measured and is shown in Table 2. In the same table, the reinforcing material and the amount added in its shape are also listed.

As is clear from the table, the composite material according to the present invention has extremely excellent bending strength.

Table 1 [Effects of the Invention] As described above, the composite material according to the present invention contains a large amount of apatite or whitlockite crystals, which are considered to be effective for chemically bonding with bone, and has a weight of 3000 kg/cr.
Indicates bending strength of n' or more. The bending strength of this composite material is much higher than the maximum bending strength of human bone, which is 1800 kg/cm'.

Therefore, the high-strength composite material according to the present invention can be used for long pipes, joints,
It is extremely effective as a structural material for areas where force is applied, such as tooth roots, and does not require mechanical fixation.

Composite materials with SiC have low electrical resistance, so electrical discharge machining is possible, and complex shapes such as bones can be easily machined.

Claims (2)

[Claims] (1) Consisting of 30 to 95 volume % of crystallized glass containing witrockite crystals or apatite crystals as main crystals and 1 to 70 volume % of reinforcing material, and the crystallized glass is essentially A biological composite material comprising: CaO 30-50 P_2O_5 40-55 Al_2O_3 8-15 MgO 0-5 SiO_2 0-10 B_2O_3 0-15 Additional components 0-10. (2) Claim 1, wherein the additional components are Zr_O_2 0-10 TiO_2 0-10 Ta_2O_3 0-10 CaF_2 0-5 Li_2O 0-5 Na_2O 0-5 K_2O 0-5 in weight percent. composite materials. (2) The reinforcing material is SiC, Al_2O_3, Si_
The composite material according to claim 1 or 2, which is at least one type of fiber, particle, or whisker selected from 3N_4 and zirconia.