To evaluate the wettability of phosphate ceramics by water, contact angles of hydroxyapatite-tricalcium phosphate composite ceramics were measured by the sessile drop and adhesion tension methods. It was difficult to obtain an equilibrium contact angle by the sessile drop method. On the other hand, reproducible values were obtained by the adhesion tension method if the sample was ground to less than 0.6mm in thickness. The contact angles of hydroxyapatite and β-tricalcium phosphate ceramics were 30.7° and 23.5°, respectively. The contact angle of the composite ceramics obtained by mixing of hydroxyapatite with tricalcium phosphate increased suggesting that the hydrophilicity of the surface decreased. The wettability of the composite ceramics increased with increasing surface hydroxyl group density measured by X-ray photoelectron spectroscopy.
