Impact of Case Difficulty, Endodontic Mishaps, and Instrumentation Method on Endodontic Treatment Outcome and Quality of Life: A Four-Year Follow-up Study

Introduction: Root canal treatment (RCT) is often considered a difficult procedure for both the patient and treatment provider. The American Association of Endodontists case difficulty assessment form categorizes cases as minimal, moderate, and high difficulty level. We recently showed that endodontic mishaps occur frequently during treatment of teeth in high difficulty category. The aims were to investigate the clinical and radiographic outcome at least 4 years after RCT and to evaluate patients' perceived oral health-related quality of life (OHRQoL). Methods: Two hundred thirty-four patients (257 endodontically treated teeth) who were previously included in a quality assurance study were offered a recall appointment at the Department of Clinical Dentistry, University of Bergen, Norway. Patients were given a thorough clinical, radiographic examination and asked to fill out the Oral Health Impact Profile -14 questionnaire. Results: A total of 149 patients (160 teeth) attended the 4-year (range, 4- 6 years) recall appointment. An unchanged or lower Periapical Index (PAI) score at recall visit was registered on 153 teeth (95.6%) (P < .001). Radiographic success rate (PAI score < 2) was 87.5%, and clinical success (absence of clinical signs and symptoms) was 88.8%. Both radiographic and clinical success was observed in 78.8% of teeth. Teeth in high difficulty category, instrumented with engine-driven files, and molars presented with significantly more clinical signs and symptoms but not high PAI score (PAI score > 3) (P < .05). Endodontic mishaps such as overinstrumentation and overfill with gutta-percha resulted in significantly high PAI score (P < .05). Patients with no clinical signs and symptoms after RCT and elderly had a significantly better OHRQoL (P < .05). Conclusions: Presence of clinical signs and symptoms rather than PAI score affected patients' OHRQoL. (J Endod 2023;49:382-389.)