Effect of degradation rates of resorbable phosphate invert glasses on in vitro osteoblast proliferation.

Four resorbable phosphate invert glasses for use as bone replacement were synthesized in the system P2O5--CaO--MgO--Na2O. TiO2 and SiO2 were added at concentrations of 1 and 5.5 mol % to control solubility and crystallization. Both bulk glasses and samples with an open porosity of 65% and pore sizes of 150 to 400 microm were produced using a salt sintering process. Addition of TiO2 decreased the solubility in water and simulated body fluid, while the glass with addition of SiO2 showed a higher dissolution rate than did the original glass. The hypothesis that dissolution rates of the glasses will affect cell proliferation of osteoblastlike cells was tested using a MC3T3-E1.4 murine preosteoblast cell line. Cells were cultured on nonporous polished and porous glasses with tissue culture polystyrene (TCPS) as control. Cell proliferation was studied over 24 and 72 h in culture. Cells proliferated on all polished glasses, but proliferation on porous glasses showed variations with glass composition. Cell proliferation increased with decreased solubility of the glass. It is suggested that resorbable implant materials require the adjustment of dissolution rate so as to facilitate cell adhesion and proliferation and thus a gradual transition from artificial implant to new bone structure. Copyright (c) 2005 Wiley Periodicals, Inc.