Press-formable CaO-MgO-SiO(2)-TiO(2)-Ag(2)O glass as a biomaterial.
Glass-ceramics were investigated to obtain a glass with a composition of CaO. MgO. 2SiO(2). 0.375TiO(2). 0.007Ag(2)O. The glass melted at 1500 degrees C and could be cast. Crystallization of diopside of this glass is controlled by volume nucleation and growth processes. In a crystallization treatment at 850 degrees -870 degrees C, this glass presented a milky white, semitransparent color. The crystals formed were diopside, their crystal grain diameter was 1-2 micrometer, and crystallization was 15-25%. The bending strength of the glass produced by a crystallization treatment of 25 min at 850 degrees C was 400 MPa, which is suitable for artificial bones. This crystallized glass also was extremely stable, with no weight loss after stability testing in artificial saliva. The softening point, as determined from the viscosity curve, was 830 degrees C, and the crystallization temperature was 895 degrees C. Thus this glass can be press-formed at a temperature of 830 degrees -880 degrees C. Actual press-forming at a pressure of 0.64 MPa was carried out for 40 min at 850 degrees C and resulted in the formation of desired shapes. Given its ready formation into desired shapes and its great strength after crystallization, such glass is applicable for use as artificial bones and as dental roots and crowns.
Nonami
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National Industrial Research Institute of Nagoya, 1-1, Hirate, Kita-ku, Nagoya, 462-8510 Japan. nonami@nirin.go.jp
Tsutsumi
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D001672:Biocompatible Materials / Q000737:chemistry*; D018786:Bone Substitutes; D002516:Ceramics / Q000737:chemistry*; D003442:Crowns; D003460:Crystallization; D005898:Glass / Q000737:chemistry*; D006358:Hot Temperature; D013314:Stress, Mechanical; D014783:Viscosity; D014961:X-Ray Diffraction
D001672:Biocompatible Materials; D018786:Bone Substitutes; C404415:CaO-MgO-SiO2-TiO2-Ag2O glass