Healing of 295 Endodontic Microsurgery Cases After Long-Term (5-9 Years) Versus Middle-Term (1-4 Years) Follow-up

Introduction: Some evidence suggests that teeth treated with endodontic surgery and considered to have healed over the short term are seen to relapse when evaluated again after 3 or more years. However, long-term evidence is limited. This study compares healing after endodontic microsurgery over long-term (5-9 years) vs middle-term (1-4 years) follow-up and assesses the influence of different healing predictors over time. Methods: A retrospective study was made, comparing the endodontic microsurgery healing rates after 1-4 vs 5-9 years of follow-up. Healing was assessed based on clinical and radiographic parameters. Simple binary logistic regression models were used to analyze the influence of patient age and gender, the type of tooth, previous radiographic lesion size, apical extent of previous root canal filling, the presence of a post, type of restoration, and interproximal bone level upon the endodontic microsurgery healing rate. A sensitivity analysis was used excluding cases of vertical root fracture. Two calibrated observers independently evaluated the periapical radiographs. Results: A total of 332 patients (60% women and 40% men) were included in the study. Of the 332 analyzed teeth, 198 were subjected to middle-term follow-up (1-4 years), with a healing rate of 86.9%, while 134 were subjected to long-term follow-up (5-9 years), with a healing rate of 67.2%. There were no statistically significant differences in terms of gender, age, type of tooth, size of the lesion, apical extent of previous root canal filling, presence of a post, or type of restoration. The regression models identified 2 statistically significant associations: cohort and interproximal bone level (P<.05). Conclusions: A success rate of 86.9% was recorded after 1- 4 years of follow-up, vs 67.2% after 5-9 years. Excluding cases of vertical root fractures, in the shortest follow-up cohort (1-4 years), the healing rate was 92.5%, vs 82.6% in the cohort with longer follow- up (5-9 years). The prognosis was influenced by the crestal bone level in relation to the cementoenamel junction of the tooth, being significantly poorer when probing depth was >3 mm mesial or distal to the treated tooth.