Composite for the fabrication of resorbable implants for osteosynthesis: biocompatibility evaluation in rabbits/Composito para fabricacao de implantes reabsorviveis para osteossintese: avaliacao da biocompatibilidade em coelhos

Biocompatibility, osseointegration, and resorption of a 10% hydroxyapatite (HAP-91®)--90% polyhydroxybutyrate composite were analyzed after implantation in rabbits' bone defects. Clinical, radiographic, histologic and histomorphometric data were collected on the 8th, 45th, and 90th days after surgery and the results were compared to those of unfilled defects. No significant differences between groups for the evaluated clinical parameters existed. Radiographs showed bone-composite direct contact. Bone tissue was formed normally in the defect and at the composite-tissue interface when compared to the control. No inflammatory infiltrated was observed. For each sampling day, the percentages of bone were greater than those of connective tissues (P=0.001 on the 8th and 45th days and 0.022 on the 90th day) inside the defect. Bone and connective tissues were seen at the interface with the composite, being the last one significantly greater than the first on the 90th day (P=0.004). Composite's resorption signs were evident: giant cells on the surface of composite fragments separated from the original bloc. Data support that such composite is biocompatible in rabbits, resorbable and integrate to bone.