Master apical file size - smaller or larger: a systematic review of healing outcomes.

The purpose of this systematic review was to determine in patients undergoing root canal treatment, whether apical enlargement affected the healing outcome. A PICO (population, intervention, comparison and outcome) strategy was developed to identify studies dealing with apical size of canal and healing outcome as measured clinically and radiographically. The MEDLINE, Embase, Cochrane and PubMed databases were searched. Additionally, the bibliography of all relevant articles and textbooks was manually searched. Based on inclusion and exclusion criteria, two reviewers independently selected the relevant articles. Four articles were identified that met the inclusion criteria. There were no studies that evaluated apical enlargement and healing outcome using cone beam computed tomography. The results of the systematic review confirmed that more evidence-based research in this area is needed. With the limited information available, the best current available clinical evidence suggests that for patients with necrotic pulps and periapical lesions, enlargement of the apical size would result in an increased healing outcome in terms of clinical and radiographic evaluations.