Evaluation of Retromolar Canals using Cone Beam Computer Tomography/ Avaliação do canal retromolar por meio de tomografia computadorizada de feixe cônico

Abstract

The aim of this study was to evaluate the prevalence, location and clinical implications related to the presence of the retromolar canal (RMC) on cone beam computed tomography(CBCT). CBCT images of patients from Latin America Institute for Dental Research and Education - Curitiba,Pr,Brazil, was performed from June/2008 to February/2013. The interpretation was performed by a calibrated examiner, according to the criterias: presence, location and classification of the RMC variation, as well as, measurements of horizontal distances of the RMC in relation to the buccal bone cortical and diameter of these canals. A total of 751 CBCT images were interpreted: 486(64.7%) from females and 265 (35.3%) from male patients, with mean age of 54.57 (±13.23) years. The presence of RMC was observed in 58 (7.7%) patients, 23 men and 35 women. A total of 1502 hemi- mandibles were analyzed. The RMC was identified in 69(4.6%) hemi-mandibles, 44(63.8%) from females and 25(36.2%) from males. Thirty (42.8%) RMC were observed on the right side and 40 (57.2%) on the left one. The type B1 (n=33; 47.1%) was the most common, followed by the type A1 (n=18;25.7%). The mean diameter of RMC was 0.97mm (±0.44), and the mean distance between retromolar foramen and the buccal cortical of the mandible was 4.12mm (±1.35). There were no significant differences between the distances and genders, and distances and sides (p 0.05). The prevalence of RMC was 7.7% in the studied sample; they were predominantly unilateral and showed to be type B1.