Master of Science (MS)
Medical Sciences Interdepartmental Area
Richard A. Reinhardt, D.D.S., Ph.D.
Background: Loss of the alveolar ridge width and height following extraction is well-documented and several techniques, including grafting, have been proposed to reduce bone loss. Purpose: To characterize the pattern of bone turnover and inflammation after extraction and to initiate a study of the effect of grafting and local administration of simvastatin (SIM). Methods: Thirty-two retired-breeder rats underwent extraction of the right maxillary first molar and standard surgical defect creation under inhalation anesthesia. The left side of each animal served as the unmanipulated control. Comparison of groups (n=8, ANOVA) was done at days 0, 7, 14, and 28 for alveolar bone height and width and for markers of inflammation and bone turnover by micro-computed tomography (µCT) and histology/ELISA. Seventeen additional specimens had the defects grafted with either bone mineral matrix (BMM) or a BMM+SIM conjugate. Results: µCT and histologic analysis demonstrated extraction-induced bone loss is most evident on the palatal (p < 0.001) and interproximal (p < 0.05) aspects of the socket. After the first week, a more intense inflammatory reaction corresponded to a reduction in alveolar bone height in the interproximal areas and alveolar bone height and width on the palatal aspect (p < 0.05). Increased numbers of osteoblasts were evident at the periphery of the socket at later time periods, particularly in the grafted specimens. BMM+SIM also reduced inflammation at 28 days (p < 0.001) and enhanced ridge width (p < 0.001). Conclusions: The standard defect used in the current study paralleled human post-extraction alveolar bone loss and defect grafting partially preserved bone.
Willett, Emily, "Bone Loss Quantification Following Extraction in Rats: A Foundation for Grafting and Regenerative Studies" (2016). Theses & Dissertations. 155.