The fate of root canals obturated with Thermafil: 10-year data for patients treated in a master’s program

Objectives: Retrospective description of the 10-year success rate of endodontic treatments with Thermafil (TF). Materials and methods: Patients treated by postgraduate students in an Endodontics Master’s Program (2006–2008) were enrolled. All treated root canals were filled with TF and AH Plus. Teeth satisfying the inclusion criteria (206 teeth in 89 patients) were reexamined clinically and radiographically to estimate a 10-year survival and periapical health. Demographic and medical data were registered; collected information included pre-, intra-, and postoperative variables. Teeth were classified as “healthy” (PAI ≤ 2 in absence of signs/symptoms), “endodontically diseased” (presenting at least one of the following: PAI ≥ 3, signs/symptoms, retreated in the course of the follow-up, or extracted for endodontic reasons), or “non-endodontically diseased” (extracted for non-restorable fractures or periodontal disease). For teeth lost during the 10-year follow-up, details and reason of extraction were analyzed. Two PAI-calibrated examiners assessed outcomes blinded to preoperative status. Bivariate and multilevel analyses were performed (α level set at 0.05). Results: At 10 years, 179 (87%) teeth survived and 27 were extracted: 20 for non-endodontic reasons (excluded from success analysis) and 7 for endodontic reasons (considered “endodontically diseased”). Multilevel analysis revealed that the probability of extraction was increased by the presence of preoperative pain (odds ratio = 6.720; 95% confidence interval, 1.483–30.448) and by maxillary location (odds ratio = 2.950; 95% confidence interval, 1.043–8.347). Concerning periapical status, 159/186 teeth (85%) were assessed as “healthy.” Multilevel analysis confirmed that maxillary location (odds ratio = 3.908; 95% confidence interval, 1.370–11.146), presence of flare up (odds ratio = 9.914; 95% confidence interval, 2.388–41.163), and fracture occurrence (odds ratio = 35.412; 95% confidence interval, 3.366–372.555) decreased the odds of healing, respectively. Conclusions: After 10 years, teeth filled with Thermafil in a specialist master’s program presented a survival and a periapical health comparable to cohorts where root canals were filled with other obturation techniques. Clinical relevance: Carrier-based techniques provide time savings for clinicians while satisfying clinical quality criteria for the root filling and consequently the clinical outcome.