Effect of Time Elapsed After Extraction on the Buccolingual Angulation of Alveolar Bone in the Posterior Mandibular Region

Introduction: The aim of this study was to evaluate the effect of time elapsed after extraction on the buccolingual angulation of alveolar bone in the posterior mandibular region using cone beam computed tomography (CBCT) images. Material & Methods: The CBCT images of 56 patients who referred to the Radiology Department of Hamadan Dental School, Hamadan, Iran, were evaluated in this study. The scans were performed using the New Tom 3G scanner. The patients were divided into three groups regarding the time elapsed after extraction, namely: 6 month-2 years, 2-5years and >5 years. Buccolingual angulation of ridge in the second premolar, first molar, and second molar areas on both sides (with and without tooth) were measured in cross-section views (slice thickness: 1mm, interval: 2mm) using NNT viewer software. The data were analyzed in SPSS software (Version. 22) through paired t-test and regression. Results: The changing of buccolingual angulation in the second molar area in each group was not statistically significant (P<0.05). In the first molar area, buccolingual angulation increased in the time elapsed after 6 months-2years and over 5 years and it was statistically significant (P<0.05). However, regarding the time elapsed between 2-5 years, the difference was close to the margin of statistical significance. In the second premolar area, changes were not statistically significant in time elapsed from 6 months to 2 years and 2-5 years; however, it was significant regarding the time elapsed after extraction of over 5 years (P<0.05). Conclusion: The elapsed time did not have any significant effect on the buccolingual angulation in the toothless area of the second molar. Regarding the first molar area, tooth extraction increased the buccolingual angulation. In addition, an increase was observed in the buccolingual angulation after 5 years of the tooth extraction at the area of the second molar.