Hoya Corporation

Toshihiro Kasuga

Kiichi Nakajima

Tomoko Kasuga

Masahiro Yoshida

Kenji Nakagawa

Tomoko Uno

A glass-ceramic which is excellent in mechanical strength, cutting processability and chemical durability and suitable for the production of an artificial dental crown and a mold, the glass-ceramic containing, by weight percentage, 2 to 17% of CaO, 0 to 5% of K.sub.2 O, 0 to 4% of Na.sub.2 O, the total content of K.sub.2 O and Na.sub.2 O being 0.5-7%, 15 to 35% of MgO, 30 to 49% of SiO.sub.2, 2 to 15% of ZrO.sub.2 and not more than 14% (calculated as F) of fluorine, and having a zirconia crystal and a mica crystal precipitated.

Glass-ceramic and artificial dental crown formed therefrom

The present invention relates to a process for producing an inorganic biomaterial, according to which, there can be obtained an inorganic biomaterial excellent in strength and biocompatibility, having a structure in which portions constituted by crystallized glass or crystals of calcium phosphate excellent in bioactivity are dispersed in a skeleton or matrix constituted by crystals of partially stabilized zirconia and/or alumina showing high strength. Accordingly, the inorganic biomaterial is very useful as biomaterial for artificial bones, dental implants, etc.

Process for producing inorganic biomaterial

Disclosed is glass-ceramics produced by and a method of producing the glass-ceramics comprising the step of precipitating a calcium-potassium mica crystal consisting of Ca-K-Mg-Al-Si-O-F and at least one crystal selected from the group consisting of an enstatite crystal, an akermanite crystal and a diopside crystal, from glass containing components, in percent by weight, 2 to 17% of CaO, 0.5 to 5% of K.sub.2 O, 20 to 35% of MgO, 30 to 50% of SiO.sub.2, 5 to 30% of Al.sub.2 O.sub.3, and 1.5 to 14% of Fluorine (Calculated as F); or precipitating a calcium-potassium-sodium mica crystal consisting of Ca-K-Na-Mg-Al-Si-O-F and at least one crystal selected from the group consisting of an enstatite crystal, an akermanite crystal, a diopside crystal, an anorthite crystal and a richterite crystal, from glass containing components, in percent by weight, 2 to 17% of CaO, 0.5 to 5% of K.sub.x O, 0.1 to 4% of Na.sub.2 O, 15 to 35% of MgO, 30 to 49% of SiO.sub.2, 5 to 30% of Al.sub.2 O.sub.3, and 1.5 to 14% of Fluorine (calculated as F). In the above method, the glass is heat treated successively at a temperature higher than its glass transition point by a range of from 10.degree. to 100.degree. C. and at a temperature higher than its glass transition point by a range of from 100.degree. to 500.degree. C. to thereby precipitate the above-mentioned matters. Further disclosed is an artificial dental crown composed of the above-mentioned glass-ceramics.

Glass-ceramics, process of producing the glass-ceramics and dental crown

The inorganic biomaterial of the present invention comprises a ceramic-crystallized glass composite wherein a zirconia ceramic, an alumina ceramic or a zirconia-alumina ceramic is dispersed in a crystallized glass composed mainly of CaO, P.sub.2 O.sub.5, MgO and Al.sub.2 O.sub.3. This inorganic biomaterial, having biocompatibility and a high strength, is useful as an implant material for artificial bones and dental implants.

Inorganic biomaterial and process for producing the same

According to the present process for modifying the surface of a biomaterial, there can be precipitated on the surface of a biomaterial a calcium phosphate crystal which is necessary for the biomaterial to form a chemical bonding with human bones. Therefore, the bioactivity of a biomaterial for use as an artifical bone or a dental implant can be improved by the present process.

Process for surface modification of inorganic biomaterial

Glass ceramic comprising apatite crystals and at least 50% by weight of wollastonite crystals and a process for producing the same are disclosed. The glass ceramic contains from 45 to 56% by weight of CaO, from 1 to less than 10% by weight of P.sub.2 O.sub.5, from 30 to 50% by weight of SiO.sub.2, from 0 to 5% by weight in total of one or two of MgO and Y.sub.2 O.sub.3, and from 0 to 5% by weight of one or more of F.sub.2, Na.sub.2 O, K.sub.2 O, Li.sub.2 O, Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2, SrO, Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5, with the total content of CaO, P.sub.2 O.sub.5 and SiO.sub.2 being at least 90% by weight. The glass ceramic exhibits excellent biocompatibility and has improved strength.

High-strength glass ceramic containing apatite crystals and a large

A high-strength glass-ceramic containing apatite crystals or .beta.-tricalcium phosphate crystals, and anorthite crystals, and a process for producing the same are disclosed. The glass-ceramic has an excellent biocompatibility and is useful as an implant material such as an artificial dental root and an artificial bone.

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Akishima, Japan

Toshihiro Kasuga