Endodontic Therapy Interventions for Root Canal Failure in Permanent Dentition: A Review of Clinical Effectiveness, Cost-Effectiveness, and Guidelines

Root canal, or endodontic treatment, is a procedure in which an inflamed or infected pulp is removed, and the inside of the tooth is cleaned, disinfected, then filled and sealed with a restorative material. The procedure has a high success rate, although persistence of symptoms or infection recurrence can occur in 10% to 15% of cases. Tooth survival over two to 10 years following initial root canal treatment was shown in a systematic review to range between 86% and 93%. In many cases of infection or symptom recurrence, a second root canal treatment (root canal re-treatment) is considered. Apicoectomy is usually needed when root canal re-treatment is not successful, and is a procedure in which the root tip, or apex, is removed along with the infected tissue, then a root end filling (retrofilling) is placed to seal the area. Factors associated with a better chance of success of apicoectomy include patients ≤ 45 years old, upper anterior or premolar teeth, cases without preoperative pain, lesions without periodontal involvement, absence of perforating lesions, and teeth with only one periapical surgery.– In the case of apicoectomy failure, the tooth may need to be extracted.This Rapid Response report aims to review the clinical and cost-effectiveness of endodontic interventions (root canal re-treatment, apicoectomy and retrofilling) after failed root canal treatment, compared to initial root canal treatment alone (no treatment) or tooth extraction. Guidelines associated with the use of root canal re-treatment, apicoectomy with or without apical curettage, and retrofilling in permanent teeth will also be examined.