Survival Analysis of Pulpectomy in Primary Molars with Apical Periodontitis and Factors Influencing Outcomes: A Retrospective Cohort Study

Background To retrospectively analyse the survival of pulpectomy in primary molars with apical periodontitis over a follow-up period of up to five years and to identify associated prognostic factors. Methods This retrospective cohort study evaluated 5-year pulpectomy survival in primary molars with preoperative radiographic evidence of apical periodontitis. Dental records of children aged 36–72 months treated between 2019 and 2021 were reviewed. Failure was defined as symptomatic progression requiring extraction or retreatment. The cumulative survival probability was analysed with the Kaplan–Meier estimator. Cox proportional hazards regression was used to identify factors associated with failure. Results A total of 326 primary molars from 242 children were included. Kaplan–Meier analysis showed complete survival during the first 12 months, with cumulative survival remaining above 95% at 24 months, followed by a gradual decline over the 5-year follow-up period. The mean survival time was 54.6 months (95% CI: 52.1–57.2), with a cumulative survival rate of 41.9% (95% CI: 26.4–57.4) at 60 months. In the multivariable model, child age at time of treatment and preoperative soft-tissue appearance were independently associated with increased failure. Compared with children aged 36–48 months, those aged 49–60 months (HR 5.42; 95% CI: 1.23–23.81) and 61–72 months (HR 5.09; 95% CI: 1.14–22.78) showed a significantly higher risk of failure. The presence of a preoperative sinus tract also markedly increased failure risk (HR 4.40; 95% CI: 1.49–13.00). Treatment-level variables, including treatment visit regimen, irrigant type, obturation material, quality of obturation, operator training level, and child cooperation status, were not significantly associated with outcomes. Conclusions Long-term pulpectomy survival in primary molars with apical periodontitis is primarily influenced by tooth-level and preoperative disease-burden variables rather than treatment-level variables. Increasing age and the presence of a sinus tract are associated with a higher rate of symptomatic progression after pulpectomy.