Bone formation through collagen/HA composite implants using a membrane technique

ABSTRACT

Atrophy of the jaws is an inevitable sequel to tooth loss. Subperiosteal implantation of collagen/hydroxylapatite [HA] composite implants in block form has been used in recent years. However, collagen is subsequently resorbed and is not replaced by new bone. This study was designed to provide histologic observations on the healing pattern related to collagen/HA implants when used in conjunction with guided tissue regeneration procedures using a membrane technique. Twelve rabbits aged 12-15 months served as the experimental animals in this study. Two compressed collagen/HA implants in block form were inserted into two defects of each rabbit calvaria. One of the two implants was covered with nonresorbable expanded polytetrafluoroethylene [ePTFE] membrane, the other implant was left uncovered. Specimens were obtained at 4, 8 and 12 weeks and examined by light microscopy. While the implant specimens on the membrane side showed progressive bone formation between and around the HA particles at the subperiosteal extra-bony locations, the HA particles on the nonmembrane side were surrounded and separated by dense fibrous tissue. At intraosseous sites, HA particles were surrounded by new bone throughout the defect on the membrane side, but this occurred only along the periphery on the nonmembrane side. It was concluded that guided tissue regeneration may be used to induce new bone formation around and between implanted HA particles