A histopathologicai investigation on the effect of systemic administration of the bisphosphonate alendronate on resorptive phase following mucoperiosteal flap surgery in the rat mandible

Background: The present study was designed to assess histopathologically whether the systemic administration of aminobisphosphonate (alendronate), 0.5 mg/kg body weight, is effective in preventing alveolar bone resorption following mucoperiosteal flap surgery, and whether alendronate modulates tissue factors.Methods: The effect of alendronate on bone resorption was evaluated in mucoperiosteal flaps used as a resorptive model. The animals were given subcutaneous injections of either saline (control group) or 0.5 mg/kg of alendronate (experimental group). The alendronate or saline was administered subcutaneously 1 week prior to surgery, immediately prior to surgery, and 1 week after surgery. The parameters determined with a semiquantitative subjective method for histopathological evaluation were as follows: inflammatory cell infiltration (ICI) of adjacent periodontal tissue, degree of fibrosis and collagen bundle formation, number and morphology of osteoclasts of the alveolar bone and interdental septum, resorption lacunae (osteoclast surfaces), and osteoblastic activity (forming surfaces).Results: There were no statistically significant differences between the saline and alendronate groups with regard to inflammatory cell infiltration, number of osteoclasts, and osteoblastic activity. Fibrosis and Collagen bundle formation, osteoclast morphologies, and resorption lacunae formation were significantly different between the two groups, in favor of the alendronate group.Conclusions: The systemic administration of 0.5 mg/kg alendronate was effective in preventing alveolar bone loss and in modulating tissue factors. These findings indicate that alendronate would be a valuable addition to the therapeutic armamentarium available for the treatment of periodontal diseases, either alone or in combination with regenerative components such as anti-inflammatory drugs, bone graft materials, and guided tissue regeneration techniques, and even with dental implants.