Histologic evaluation of combining tetracycline and allogeneic freeze-dried bone on bone regeneration in experimental defects in baboons.

Tetracyclines (TTC) have been used both systemically and locally during periodontal bone grafting procedures, but previous work regarding the effect of TTC on new bone formation has been contradictory. The purpose of this study was to determine if the use of locally applied TTC in combination with freeze-dried bone allografts (FDBA) would enhance bone regeneration in an experimental alveolar bone osseous defect grafting system. Pre-weighed freeze-dried bone allograft particles (300-500 mu diameter) were placed in nylon mesh chambers (250 mu pore size) and rehydrated with either 10 micrograms/ml aqueous TTC or sterile distilled water. Empty chambers were used as further controls. The chambers were placed in the posterior mandible of baboons in surgically created windows. After 3 and 5 weeks, the chambers were retrieved, processed histologically, and analyzed histometrically for new bone formation. The TTC-rehydrated FDBA demonstrated much greater (greater than 5x) new bone formation than the water rehydrated FDBA. These results strongly suggest that locally-applied TTC in combination with FDBA enhances new bone formation in experimental alveolar bone defects.