Thermal and mechanical properties of hydroxyapatite impregnated acrylic bone cements

Improvement of mechanical, thermal and biological properties of acrylic-based bone cements by adding various chemicals is a novel research area. Among these additives, hydroxyapatite (HA) is proven to be a biocompatible and osteoconductive material and it strongly integrates with bone. In this study, HA-containing acrylic bone cements were prepared and thermal and mechanical properties of the resultant cements were examined. In order to achieve a proper and homogeneous distribution of HA particles in the polymer matrix, very low viscosity cement compositions were prepared by mixing poly(methylmethacrylate) particles with two different molecular weights. Addition of HA into the cement increased the viscosity while making workability easier. With this novel formulation, polymerization temperature decreased from I I I to 87 degreesC, compressive strength increased from 96 to 122 MPa and sufficient compressive fatigue strength of 77 MPa at 10(6) cycles was provided. HA-containing acrylic bone cements demonstrated higher mechanical strength than the reference cement. The screening tests by in vivo applications achieved biological compatibility. It can be concluded that HA-containing acrylic bone cement may effectively be used in the clinical field in the future. (C) 2003 Elsevier Ltd. All rights reserved.