JPH0622572B2 - Zirconia implant material for living body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a biomedical implant material used in medical technology such as dentistry and orthopedics.

(Prior Art) Conventionally, as a medical implant material, in addition to a metal having a high corrosion resistance such as stainless steel or a titanium alloy, alumina ceramics without elution of metal ions is often used. Furthermore, in recent years, like the alumina ceramics, there is no elution of metal ions,
Moreover, partially stabilized zirconia, which has high strength and high toughness, is being used as a biomedical implant material.

(Problems to be solved by the invention) However, in the above-mentioned conventional ones, in the case of stainless steel, titanium alloy, etc., when they are buried in the body for a long period of time, corrosion partially progresses due to the influence of body fluid. In addition, the processing cost increases because it is very difficult to process according to the shape of the buried part, and in the case of partially stabilized zirconia, the tetragonal ZrO _{2 on the} surface gradually becomes monoclinic due to long-term implantation in the body. If it is transformed into crystalline ZrO ₂ and this transformation progresses to a certain extent or more, the strength is deteriorated. Therefore, the present invention solves the above-mentioned drawbacks of the conventional ones, and makes it possible to use partially stabilized zirconia having excellent properties as a biomedical implant material.

(Means for Solving Problems) Therefore, Y ₂ O ₃ is contained in an amount of 2 mol% or more and less than 6 mol%, which is obtained by a coprecipitation method, a hydrolysis method, or the like.
It is intended to provide a zirconia implant material for living body in which the particle size of a sintered body obtained by compacting and sintering fine powder of partially stabilized zirconia having a good dispersibility of ₂ O ₃ is 0.8 μm or less.
Further, Al ₂ O ₃ and / or TiN is added to the zirconia layer of 150
% Or less and molded and sintered to provide a biological zirconia implant material having a crystal grain size of 0.8 μm or less.

(Operation) With the above-described configuration, even if the body is exposed for a long period of time, it is possible to prevent the change of the crystalline state of ZrO _{2 on} the surface and prevent the deterioration of strength.

(Example) The present invention will be further described with reference to an example shown in the drawings. (1)
Is an artificial hip joint which is an embodiment of the present invention, and the artificial hip joint (1) is a head ball that is loosely fitted in a socket.
(2) and a support part (3) embedded in the body so that it can be firmly held as an artificial hip joint. This head ball (2)
A sintered body containing Y ₂ O _{3 in an amount} of 2 mol% or more and less than 6 mol% and using a fine powder raw material obtained by a coprecipitation method or a hydrolysis method and having an average particle size of 0.8 μm or less. Therefore, even if the artificial hip joint (1) is exposed to body fluid by being embedded and loosely fitted in the body, the crystal on the surface of the epiphyseal ball (2) changes from tetragonal ZrO ₂ to monoclinic ZrO ₂ . Since this can be prevented to a minimum, deterioration of strength caused by the phase transition can be prevented. Further, Al ₂ O ₃ and TiN are added in an amount of 150% by weight or less to the above-described fine powder of partially stabilized zirconia, and even if a similar head ball (2) is manufactured, strength deterioration can be sufficiently suppressed. Thus, A: Y ₂
A coprecipitated YSZ (Y ₂ O ₃ partially stabilized zirconia) raw material with an O ₃ amount of 2.6 mol% was used, and the sintered body had a grain size of 0.8 μm.
m, B: coprecipitated Y with an amount of Y ₂ O ₃ of 2.6 mol%
A raw material obtained by adding 50% by weight of Al ₂ O ₃ to an SZ raw material and sintering the raw material to have a particle size of 0.8 μm, and C: Y ₂ O ₃ amount 2.6 mo.
1%, Y ₂ O ₃ · ZrO ₂ simple raw material mixture, particle size 0.8 μ
m, D: Y ₂ O ₃ amount 2.6 mol%, coprecipitated YSZ raw material, particle size 1.5 μm, E: Y ₂ O ₃
1.9 mol%, coprecipitated raw material, sintered body particle size 0.8 μm, 5 types of above A to E epiphysisal balls were immersed in 37 ° C physiological saline and Ringer's lactate solution for corrosion resistance experiment. The sample was immersed for 700 days, and the surface was periodically inspected by X-ray. As a result, in A and B, the change in the crystal phase of the sample surface portion was 20% or less, and a saturated state was shown over time. C, D
And E showed a tendency that the amount of change exceeded 40% and further increased. Further, as a result of performing a bending strength test on the samples A to E, deterioration was observed except for A and B, whereas A and B retained the original strength and The effect was fully observed. Note that (4) is a brim portion that prevents excessive embedding.

(Effects of the invention) As described above, by suppressing the transition of the crystalline phase of the zirconia implant material for living body, the deterioration of the strength caused by the phase transition is prevented, and even if it is embedded in the human body for a long time, It has an excellent effect of exerting its function.

[Brief description of drawings]

 FIG. 1 is a partial sectional perspective view of the present invention. 1 ... Artificial hip joint, 2 ... Bony head ball, 3 ... Support part.

Claims (2)

[Claims] 1. A partially stabilized zirconia fine powder containing Y ₂ O _{3 in an amount} of 2 mol% or more and less than 6 mol% and having a good dispersibility of Y ₂ O ₃ obtained by a coprecipitation method or a hydrolysis method was compacted and sintered. A biological zirconia implant material having an average sintered body particle size of 0.8 μm or less. 2. The partially stabilized zirconia fine powder is mixed with Al.
_The zirconia implant material for living body according to claim 1, which is obtained by forming and sintering ₂ O ₃ and / or TiN added in an amount of 150% by weight or less.