Prognostic factors for the survival of primary molars following pulpotomy with mineral trioxide aggregate: a retrospective cohort study

Objectives: The aim of the present study was to evaluate potential factors influencing the success rates of mineral trioxide aggregate (MTA) pulpotomy performed in primary molars. Materials and methods: A total of 347 teeth treated between March 2012 and December 2016 in 258 patients, with a mean age of 5.3 ± 1.7 years, were included in the analysis. Kaplan-Meier analyses were used to analyze were used time to failure. Multivariate Cox regression analysis with shared frailty was used to evaluate the clinical factors associated with failures. Results: The mean (standard deviation) follow-up period was 35.8 (19.6) months. Within 84 months, the survival rate was 87.1%. In multivariate Cox regression, treatment performed in lower primary molars had a lower survival rate than upper primary molars (hazard ratio [HR] = 3.38, P = 0.012). Caries extension below the cemento-enamel junction had more risk of failure (HR = 10.9, P < 0.001). Final restoration using resin-modified glass ionomer or amalgam (direct filling) had a lower survival rate than stainless steel crown (HR = 5.62, P = 0.002). Conclusions: Clinical variables such as arch type, degree of caries extension, and type of final restoration may affect the survival of primary molars following MTA pulpotomy. Clinical relevance: The results of this study indicate that specific clinical variables can be used to predict the prognosis of MTA pulpotomy in primary teeth, and estimate the risk of treatment failure. Assessments of these variables should be performed in the context of evidence-based clinical decision making.