Press-formable CaO-MgO-SiO2-TiO2-Ag2O glass as a biomaterial

Glass-ceramics were investigated to obtain a glass with a composition of Ca O . MgO . 2SiO(2) . 0.375TiO(2) . 0.007Ag(2)O. The glass melted at 1500 deg rees C and could be cast. Crystallization of diopside of this glass is cont rolled by volume nucleation and growth processes. In a crystallization trea tment at 850 degrees-870 degrees C, this glass presented a milky white, sem itransparent color. The crystals formed were diopside, their crystal grain diameter was 1-2 mu m, and crystallization was 15-25%. The bending strength of the glass produced by a crystallization treatment of 25 min at 850 degr ees C was 400 MPa, which is suitable for artificial bones. This crystallize d glass also was extremely stable, with no weight loss after stability test ing in artificial saliva. The softening point, as determined fron the visco sity 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 degr ees-880 degrees C. Actual press-forming at a pressure of 0.64 MPa was carri ed 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 streng th after crystallization, such glass is applicable for use as artificial bo nes and as dental roots and crowns. (C) 2000 John Wiley & Sons, Inc.