Hydroxyapatite-based composite for dental implants:: an in vivo removal torque experiment

Screw-shaped dental implants were fabricated from commercially pure Ti (c.p. Ti) and HA-based composites. The HA-based composites were fabricated by mixing HA with Al2O3-coated ZrO2 powders. The mechanical properties of these composites were enhanced by a factor of 3. These were implanted into the rabbit tibiae and the removal torque to loosen the implants in vivo was measured in order to investigate the osteointegration. After a healing period of 6 weeks, the implants were retrieved with a torque gauge instrument. The HA-based composite implants showed an almost 2-times-higher removal torque when compared to the Ti implants (ANOVA, p < 0.05), indicating excellent biocompatibility to bone. Thus, HA-based composites had not only better mechanical properties but also similar bioactivity as HA itself. It is believed that a HA-based composite is suitable for artificial dental implants. (C) 2002 Wiley Periodicals, Inc.