An in vivo study of the use of a nonresorbable ceramic hydroxyapatite as an alloplastic graft material in periapical surgery.

This study evaluated reactions to a hydroxyapatite after endodontic treatment and periapical surgery. Thirty-eight root canals in two Macaca speciosa monkeys were endodontically treated. Apicoectomy was then performed, leaving bony defects at the apex of each root. The defects were either packed with Durapatite ceramic crystals or allowed to fill with blood. Each animal received at least one dose of Procion red, a hard-tissue marking agent. After healing periods of 2 to 6 months, the apices were examined clinically, radiographically, and histologically. The ceramic material was well tolerated clinically with no gross evidence of inflammation or rejection. Histologically, the material was biocompatible. Healing of the experimental sites consisted of an initial investment of the apatite crystals in fibrous connective tissue followed by eventual replacement of the connective tissue with bone. Despite its excellent biocompatibility, the material appeared to retard osteogenesis by its physical presence. Although the ceramic eventually became entrapped in bone, without an intervening layer of connective tissue, there was a significantly greater amount of new bone in control sites.