Histological study on bone response to resin-hydroxyapatite

Resin-Hydroxyapatite has been developed to take the advantages of bioactivity of hydroxyapatite (HAP) and plasticity of resin (Bis-GMA). It was composed of 75% HAP, 15% Bis-GMA and 10% quartz reinforced filler. Tested pellets of Resin-HAP as well as its constituents were implanted into subcutaneous connective tissue of femurs of adult dogs. Histological observation at 12 weeks postoperatively showed that each pellet was surrounded by the fibrous connective tissue almost free of the inflammatory cells. The thickness of the fibrous layer around HAP was relatively thin, while those around Bis-GMA and Resin-HAP showed some variance. Taking our previous data into consideration, it was suggested that Resin-HAP had bio-compatibility both in soft tissue and bone, although its long-term stability as well as its stability under function should further be examined.