Patient and Clinical Characteristics Associated with Primary Healing of Iatrogenic Perforations after Root Canal Treatment: Results of a Long-term Italian Study

Introduction There are few data on the long-term efficacy of mineral trioxide aggregate (MTA) in treating root canal perforations. We investigated the extent of primary healing after perforation repair with MTA and non-healing as a result of repair. We also investigated patient/clinical characteristics affecting treatment outcomes and long-term prognosis. Methods This was a prospective cohort study that enrolled consecutive patients with a single dental perforation treated with MTA (January 1999-June 2009). Patients were followed up until December 2012 for a maximum of 13 years after treatment, with analyses carried out at 8 years. Results Of the 110 patients (median age, 36 years; 54.5% male) eligible for inclusion, 101 were judged to have started to heal at the first (n = 98, 89%) or second (n = 3, 3%) annual post-treatment checkup, and 9 (8%, 4 women and 5 men, aged between 18 and 65 years) did not show any sign of healing. Patients >50 years had a higher percentage of non-healing perforations compared with those ≤50 years (12% versus 7%). The percentages of perforations at post-treatment analysis that failed to heal were 13% (intermediate/middle), 4% (coronal), and 0% (apical). The percentages of non-healing perforations according to size were 16% for >3 mm, 6% for 2-3 mm, and 0% for smaller perforations. Characteristics associated with probability of progressing after initial healing were gender, positive probing, size, and site of perforation. Conclusions Our results show that having obtained primary healing with MTA, the likelihood of progressing is very low. They provide good evidence of the combined effectiveness of experienced operators and use of state-of-the-art materials.