Factors influencing the outcome of nonsurgical root canal treatment and retreatment: A retrospective study.

This study assessed the influence of diverse variables on the outcome of nonsurgical root canal treatment/retreatment. In general, 304 teeth from 218 patients were treated/retreated and the outcome evaluated by the periapical index (PAI). Teeth with apical periodontitis lesions that have not completely healed were classified as success or failure based on lenient and rigid criteria, respectively. Findings were evaluated using a logistic regression analysis. The overall success rates were 74% and 82% using the PAI-rigid and lenient success criteria, respectively. Specifically for treatment, the success rates were 73% (rigid) and 82% (lenient), while for retreatment they were 78% (rigid) and 83% (lenient). The treatment outcome was negatively affected by overextension, presence of preoperative lesion, lesion size >10 mm, and higher number of treatment visits (with no intracanal medication). Regarding retreatment, the chance of success was greater for teeth with adequate coronal restorations.

Distance and Bone Density between the Root Apex and the Mandibular Canal: A Cone-beam Study of 9202 Roots from a Brazilian Population.

INTRODUCTION: Accidental damage to the inferior alveolar nerve is of concern during endodontic treatment of the posterior mandible teeth, and a careful evaluation of the relationship between the apices and the mandibular canal (MC) is mandatory to prevent iatrogenic complications. This study aimed to assess the distance between the root apices of posterior teeth and the MC and the bone density in such areas. METHODS: One thousand retrospective cone-beam computed tomographic scans were randomly selected from a private oral radiologic clinic database. The images were acquired with a limited field of view and analyzed by 2 evaluators who measured the shortest distance between the root apices and the upper cortical bone of the MC using Dental Slice software (Bioparts Biomedical Prototyping, Brasília, DF, Brazil). In addition, bone density was estimated using the tool "profile line of Hounsfield" and expressed in Hounsfield units. RESULTS: The distal root of the right second molars was the closest to the MC (mean = 3.41 mm), and the right first premolar root was the farthest from the MC (mean = 5.87 mm), respectively. The root apices were closer to the MC in women than in men (P < .05). In 1.79% of the cases, the roots were in contact or invading the MC, whereas 8.35% of the root apices were close to the MC (<1.00 mm), and 89.85% were distant from the MC (>1.00 mm). In 85.55% of the cases, the bone was dense. CONCLUSIONS: The results suggest that the risk of damage to the inferior alveolar nerve is higher for second molars, especially in female patients. The higher density of the adjacent bone may act as a protective factor against nerve damage arising from endodontic procedures.