Impact of selective alveolar decortication on bisphosphonate burdened alveolar bone during orthodontic tooth movement

Objective: To investigate the effect of Selective Alveolar Decortication (SADc) facilitated orthodontic tooth movement (OTM) on bisphosphonate burdened alveolar bone in a rodent model. Design: OTM was accomplished by protraction of the maxillary right first molars. Four groups were included of which two groups were pre-treated for three months with alendronate sodium (BP +TM + SADc and BP + TM group) and two groups were given saline (TM + SADc and TM group). Selective alveolar decortication surgery was performed on day 1 of appliance insertion. OTM measurements were obtained at 0, 4, and 8 weeks using in-vivo mu CT. Tissues were analysed by histology and EPMA. Results: Tooth movement of 0.39 mm and 0.75 mm in the BP +TM + SADc group at 4 and 8 weeks respectively was achieved with 113% increase in tooth movement compared to BP +TM group at 4 weeks. In comparison, SADc +TM group showed 0.63 mm and 2.1 mm of tooth movement at 4 weeks and 8 weeks respectively with only 6% increase at 4 weeks and 2% increase at 8 weeks compared to TM group. Severe interproximal and buccal bone loss around the first permanent molar in the BP +TM + SADc group was seen with mu CT imaging and histology. Animals in BP +TM + SADc group histologically showed signs of osteonecrotic bone with irregular borders, loss of osteocytes and absence of osteocytic lacunae. Conclusion: This study demonstrated selective alveolar decortication accelerates tooth movement in a bisphosphonate burdened alveolar bone in the short term but the potential of such an invasive injury can have adverse effects. (C) 2015 Elsevier Ltd. All rights reserved.