HISTOMORPHOMETRICAL ANALYSIS OF THE EFFECTS OF THE BISPHOSPHONATE ALENDRONATE ON BONE LOSS CAUSED BY EXPERIMENTAL PERIODONTITIS IN MONKEYS

This study tested the efficacy of alendronate, a bisphosphonate, in reducing alveolar bone loss caused by experimental periodontitis in cynomolgus monkeys. Periodontitis was initiated in adult monkeys by ligating mandibular molar teeth at the cementoenamel junction (CEJ) and subsequently inoculating the ligature with Porphyromonas (Bacteroides) gingivalis. Controlateral, homologous non-ligated teeth served as controls. Animals received, intravenously, either saline (placebo) or alendronate at 0.05 or 0.25 mg/kg every 2 weeks for 16 weeks. After the animals were sacrificed, coronal sections through mandibular molars were subjected to histomorphometrical analysis. No overt side-effects were observed in any of the animals participating in this study. In placebo-treated animals, ligation and inoculation resulted in significant bone loss both at the CEJ and at the furcation. Alendronate at 0.05 mg/kg significantly reduced bone loss associated with the experimental periodontitis at both sites. In contrast, the dose of 0.25 mg/kg was ineffective in attenuating alveolar bone loss in the furcation area and only slightly effective in preventing it at the CEJ area. The results of the histomorphometric analysis correlate closely with those of the radiographic analysis of the same experiment. These data indicate that alendronate could reduce the loss of alveolar support associated with periodontitis and suggest that bisphosphonates, by virtue of their significant inhibitory action on osteoclasts, may become a treatment modality in the battle against alveolar bone destruction during periodontal disease.