Influence of TiO2 and Ag2O addition on tricalcium phosphate ceramics

Abstract

Degradation of implanted ceramics allows for bone in-growth and eventual replacement with natural tissue. Calcium phosphate-based materials have gained the most significant attention because of their excellent biocompatibility and compositional similarities to natural bone. Adding various dopants to these ceramics significantly influences critical properties. In this study, tricalcium phosphate (TCP) compacts were fabricated via uniaxial compression with four compositions: (i) pure TCP, (ii) TCP with 1.0 wt % TiO₂, (iii) TCP with 0.5 wt % Ag₂O, and (iv) ternary of TCP and 1.0 wt % TiO₂, and 0.5 wt % Ag₂O. These compacts were sintered at 1250°C for 4 h to obtain dense ceramic structures. Phase analyses were carried out using an X-ray diffractometer. The presence of TiO₂ in TCP improved densification and increased compression strength from 70 (±25) to 145 (±40) MPa. The ternary composition had the highest density and compression strength of 180 (±15) MPa. Human osteoblast cell growth behavior was studied using an osteoprecursor cell line (OPC 1) to assure that the biocompatibility of these ceramics was not altered due to the dopants. For long-term biodegradation studies, density, weight change, surface microstructure, and uniaxial compression strength were measured as a function of time in a simulated body fluid (SBF). Weight gain in SBF correlated strongly with precipitation viewed in the inter-connected pores of the samples. After 3 months in SBF, a 35% drop in compression strength was noticed for pure TCP, but for doped compositions, no strength loss was noticed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007