OR31 - The Outcome and Predictive Variables of Endodontic Microsurgery: A Retrospective Cohort Study

Introduction: Outcome studies are integral to evidence-based endodontics. The aim of this retrospective cohort study was to evaluate the rates of and predictors for periapical healing and survival to reintervention of endodontic microsurgery (EMS).

Methods: The dental records and available radiographs of patients who received EMS at the Graduate Endodontic Clinic, University of Toronto, from 1999 to 2021, were examined. Each tooth was followed until the point of last clinical or radiographic contact or until the occurrence of an untoward event. The descriptive analyses and the estimation of the proportion of cases that survived were performed. Periapical healing analyses is underway and the prognostic factors will be investigated using multiple logistic and Cox regression analyses P < .05).

Results: 235 teeth (188 patients) were included. Most patients were females (59.1%) and over 45 years old (77%). The study teeth were mostly maxillary (71.1%) and non-molar (72.8%). They received root resection ≤4 mm (92.9) with MTA (74.9%) or bioceramic putty (25.1%) retrofill. Preoperative diagnoses were chronic apical abscess (29.8%), apical periodontitis asymptomatic: (33.3%; symptomatic: 29.2%), and acute apical abscess (7.7%). Of the 83 biopsies, 74.7% were granulomas and 25.3% were cysts. After a mean follow-up time of 3.5 years, 193 teeth (82%) survived with no subsequent intervention, while 16 teeth (7%) survived with subsequent interventions [apical surgery (n=11), root amputation (n=2), non-surgical root canal retreatment (n=1), hemi-section (n=1), and exploratory surgery (n=1)]. The remaining 26 teeth (11%) were extracted mostly for restorative reasons.

Conclusions: The survival rate of teeth which underwent EMS was high.