Outcomes and Prognostic Factors of Auto-Transplanted Immature Third Molars: A 15-Year Retrospective Cohort Study

To evaluate long-term survival, complete healing, and replacement root resorption after immature third-molar auto-transplantation and identify prognostic factors.

This retrospective single-centre cohort included 108 patients (116 immature and open-apex third molars) treated from 2002 to 2018. Fully mature closed-apex donor teeth were excluded. Survival and complete healing were estimated using Kaplan-Meier analysis, and prognostic factors were assessed using Cox proportional-hazards models. Replacement root resorption was explored using an exploratory logistic regression model. Mean follow-up duration was 4.9 ± 3.6 years (range, 0.5-15.5 years).

Among 116 transplants, 13 (11.2%) were lost during follow-up. Estimated survival was 87.6% at both 5 and 10 years and 81.3% at 15 years; the corresponding complete-healing success estimates were 83.7%, 81.2%, and 75.4%. In the adjusted Cox model, age, donor-root length status, and reason for extraction were associated with survival and complete-healing outcomes. For replacement root resorption, the exploratory logistic model showed associations with age and donor-root length status, whereas fixation method and reason for tooth extraction were not significant.

Immature third-molar auto-transplantation showed favourable estimated long-term survival, particularly in fresh extraction sockets. Age, recipient-site status, and donor-root length status should inform case selection and follow-up.