Surface hydrophilicity is considered
to have a strong influence on the biological reactions of bone-substituting
influence of a hydrophilic surface on osteoconductivity is not completely
clear, especially for superhydrophilic surfaces. In this study, we conferred superhydrophilic
properties on anodized TiO2 coatings using a hydrothermal treatment, and developed a
method to maintain this surface until implantation. The osteoconductivity of
these coatings was evaluated with in vivo tests.A hydrothermal
treatment made the surface of as-anodized samples more hydrophilic, up to a water contact angle
of 13 (deg.). Storage in both air and distilled water increased the water contact
angle after several days because of the adsorption of hydrocarbon. However,
storage in phosphate buffered solution led to a reduction in the water contact
angle, because of the adsorption of the inorganic ions in the solution, and the
sample retained its high hydrophilicity for a long time. As the water contact
angle decreased, the hard tissue formation ratio increased continuously up to
58%, which was about four times higher than the hard tissue formation ratio on
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