Calcium phosphate induction by sol-gel-derived titania coatings on titanium substrates in vitro.

Titanium and its alloys are used widely in the manufacture of orthopedic and dental implants. Sol-gel-prepared titania is able to stimulate bone-like apatite formation in in vitro and in vivo cultures. These materials can be used, for example, as coatings on dental and orthopedic implants. However, the processes that lead to apatite formation are not fully understood. In this study different kinds of titania coatings on commercially pure titanium (c.p. Ti) were tested for apatite-forming ability. The rate of apatite formation is considered to be descriptive of a material's bioactive (bone-bonding) potential. Apatite-forming tests were done in simulated body fluid (SBF). Apatite-forming ability was highest with the addition of valeric acid to sol (600 degrees C) or with sintering sol-gel coatings at 450 degrees-550 degrees C. At that temperature range calcium phosphate forms on the coatings in 1 week. Calcium phosphate forming is observed in 1 day on standard coatings sintered at 500 degrees C.