Method: Between January 2010 and June 2010, 250 patients underwent to cone beam computerized tomography (CBCT) for dental treatment planning were randomly selected for this study, all from a private Oral Radiology Clinic, Recife, Pernambuco, Brazil. Thus, 500 hemimandibles were retrospectively assessed. CBCT imaging was performed using an i-CAT New Generation® (Imaging Sciences International, Hatfield, Pennsylvania, USA) unit. Bifid mandibular canals were classified into five types: retromolar, dental, anterior, lingual and vestibular. The images were evaluated by two oral and maxillofacial radiologists with 10 years of experience. Differences in the bifid mandibular prevalence were analyzed using chi-square statistics, considering a significance of 5%.
Result: From the 250 patients, 155 (62%) were females and 95 (38%) males, with a proportion female:male of 1.6:1. Three hundred eleven (62.2%) mandibular canals were normal and 189 (37.8%) bifid. Regarding to the bifid mandibular canals, 62 (12.4%) were dental, 56 (11.4%) retromolar, 39 (7.8%) lingual, 3 (0.6%) anterior and only 1 (0.2%) vestibular. In 28 sides, multiple bifurcations were observed, including retromolar/dental (8 cases – 1.6%), retromolar/lingual 8 cases – 1.6%), dental/lingual (8 cases – 1.6%) and retromolar/dental/lingual, retromolar/anterior, dental/anterior and dental/vestibular with 1 case each. The bifid mandibular canals types dental, retromolar and lingual were most common in female patients. The retromolar, dental and lingual types were significantly more frequent than anterior and vestibular types (p<0.0001). However, there was not statistically significant difference between the association of bifid mandibular canal and the affected side.
Conclusion: The presence of bifid mandibular canals is very common, mainly dental, retromolar and lingual bifurcations. Therefore, the patients should be carefully evaluated to avoid any damage in nerve or vascular tissues within of such anatomical structure.