(PR026) Clinical Outcomes and Predictors of Intentional Replantation of Mandibular Second Molars Using Cone-beam Computed Tomography: A Retrospective Cohort Study

Objectives: This retrospective study aimed to investigate the treatment outcomes of intentional replantation (IR) of mandibular second molars in a cohort and the influence of related predictors.

Methods: A cohort of patients records subjected to IR of mandibular second molar with complete clinical and radiographic records for 0.5-10 years were investigated retrospectively excluding teeth with preoperative root defects. Cumulative survival rates were calculated by the Kaplan-Meier survival analysis and Cox proportional hazard regression model. CBCT profiles were analyzed by Pearson chi-squared test and logistic regression to identify significant predictors on healed status and survival (p < 0.05).

Results: Total 75 cases were included (45.3% men, 54.7% women; C-shaped canal, 73.3%) with 69.6-months of mean follow-up period (range, 3-115 months). The overall cumulative survival rates were 93.3% at 1-year, 81.9% at 5-years, and 72.7% at 10-years. The survival and healed rates were significantly affected by surgeon and loading timing after IR (p < 0.05). CBCT analysis revealed that the remaining root length attached to alveolar bone significantly correlated with survival (p < 0.05). Of the 62 teeth survived at 5-years, cumulated healed rate was 87.1%.

Conclusions: This retrospective cohort study of IR presented a cumulative 5-year survival rate of 81.9% with healed rate of 87.1%. Preoperative status of remaining root length attached to alveolar bone and postoperative loading timing were significant predictors after IR in cohort. Further studies are needed to identify the factors contributing to successful treatment outcomes and to understand the reasons behind failed cases in long-term perspectives.