Composition influence on properties of acrylic composites loaded with synthetic hydroxyapatite

A study of composition influence over some properties of acrylic composites loaded with hydroxyapatite is presented. "Two pastes" method from dental obturants was used to prepare the composites. The working (2.5 < t w < 3.3 min) and setting (2.7 < t s < 3.7 min) times was in range reported for acrylic bone cements and enthalpy (around 40-60 kJ/mol) according to reports for acrylic materials. The absorption (110-240 μg/mm3) and solubility (10-130 μg/mm3) showed values higher than normalized ranges. Mechanical properties (compression strength and elastic modulus) showed a wide range result, including in some cases, better values than reported by other authors. The drug release from the composites was studied through Baker's treatment which justifies not only diffusion, but the migration and dissolution of drug in the phosphate buffer. The diffusion coefficients (10-10 cm2/s) and 15-20 % of drug release at 15 days support this result too.