Age and Timing of Pulp Extirpation as Major Factors Associated with Inflammatory Root Resorption in Replanted Permanent Teeth

Introduction: External root resorption (ERR) is a serious complication after replantation, and its progressive inflammatory and replacement forms are significant causes of tooth loss. This retrospective study aimed to evaluate the factors related to the occurrence of inflammatory ERR (IERR) and replacement ERR (RERR) shortly after permanent tooth replantation in patients treated at the Dental Trauma Clinic at the School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil. Methods: Case records and radiographs of 165 patients were evaluated for the presence, type, and extension of ERR and its association with age and factors related to the management and acute treatment of the avulsed tooth by using the logistic regression model. Results: The patient's age at the moment of trauma had a marked effect on the ERR prevalence and extension. The patients older than 16 years at the moment of trauma had less chance of developing IERR and RERR (77% and 87%, respectively) before the pulp extirpation, regardless of the extension of the resorption. The patients older than 11 years of age at the moment of trauma showed the lowest indices of IERR (P = .02). Each day that elapsed between the replantation and the pulp extirpation increased the risk of developing IERR and RERR by 1.2% and 1.1%, respectively, and also raised the risk of severe IERR by 0.5% per day. Conclusions: The risk of mature teeth developing severe IERR before the onset of endodontic therapy was directly affected by the timing of the pulpectomy and was inversely proportional to age. Systemic antibiotic therapy use had no effect on the occurrence and severity of IERR in mature teeth. The occurrence of RERR before the onset of endodontic treatment stimulates further investigations of the early human host response to trauma and subsequent infection.