Outcomes of apexification in immature traumatised necrotic teeth and risk factors for premature tooth loss: A 20-year longitudinal study.

Background/aim: To evaluate the long-term survival of immature traumatized incisors with pulp necrosis and apical periodontitis after endodontic treatment with two apexification techniques (calcium hydroxide apexification and MTA-apical plug) and to identify major factors affecting the survival of these teeth.

Materials and methods: Records of 2400 children and adolescents were screened for presence of traumatic dental injuries to immature incisors where endodontic treatment with the two apexification techniques was performed during January 2003 and December 2022, compared to a control group of mature teeth treated with conventional endodontic techniques. The studied variables were age; sex; apexification technique, presence of luxation and hard tissue injuries; preoperative root development stage (RDS), preoperative and postoperative periapical index (PAI), the time-point for tooth loss, and overall survival time in years. Kaplan-Meier estimates were used to graphically present the survival functions and Cox proportional hazard model to calculate hazard ratios (HR, 95% CI).

Results: The median survival time was 10 years for calcium hydroxide apexification, 16.1 for MTA-apexification, for luxation injuries other than intrusions and avulsions 15.5 years, for intrusions 12.5 years and for avulsions 6.8 years. The variables with significant negative impact on tooth survival were calcium hydroxide apexification, avulsion and postoperative PAI 3-5. No significant relationships were found for the variables MTA apexification, concussion; subluxation; lateral luxation; extrusion, intrusion, hard tissue injuries, preoperative RDS and PAI scores and postoperative PAI 1-2. After adjustment, the risk for premature tooth loss was 13.5 times higher in calcium hydroxide apexification, approximately 2 to 4 times higher in PAI 3-5, and 5.6 times higher in avulsions.

Conclusions: Calcium hydroxide apexification, avulsion, and postoperative PAI 3-5 were identified as prognostic variables with significant negative impact on the risk for premature tooth loss.