The effect of heat treatment on bone-bonding ability of alkali-treated titanium

The purpose of this study was to evaluate the bone-bonding ability of alkali-treated titanium with and without heat treatment. Three groups of smooth titanium plate were prepared: control, or pure titanium, alkali-treated titanium, and alkali- and heat-treated titanium. The plates were inserted transcortically into the proximal metaphyses of bilateral rabbit tibiae. The tensile failure loads between implants and bones were measured at two time intervals using a detaching test. The tensile failure loads of the alkali- and heat-treated titanium group were 2.71 and 4.13 kgf, at 8 and 16 weeks, respectively, and significantly higher than those of the other titanium groups. Histological examination revealed that alkali- and heat-treated titanium was in direct contact with bone, but the other titanium groups had a thin intervening fibrous tissue. This result indicated that the alkali-treated titanium without heat treatment had no bone-bonding ability due to the unstable reactive surface layer of alkali-treated titanium. In conclusion, both alkali and heat treatment are essential for preparing bioactive titanium and this bioactive titanium is thought to be useful for orthopedic implants with cementless fixation. (C) 1999 Elsevier Science Ltd. All rights reserved.