Anatomical relation of third molars and the retromolar canal

The study was designed to assess, by direct anatomical observations and cone-beam computed tomography (CT), the prevalence of a retromolar canal and foramen in relation to the mandibular third molar in dry human mandibles. Dry mandibles from European skeletons (n=89) were observed directly and after cone-beam CT scanning (Newtom VGI evo). The following variables were assessed: the presence of a retromolar foramen and canal; the presence of a third molar, and orientation of the third molar. From the total of 89 mandibles selected, 73 showed a retromolar foramen (49 of which were bilateral). A retromolar canal was identified in 64 mandibles based on cone-beam CT assessment, with a total of 101 canals, including 74 that were bilateral. A total of 112 hemimandibles contained a third molar. Orientation of the third molar did not seem to indicate the presence of retromolar foramina or canals. A similar prevalence of retromolar canals was found for both vertically (41/79) and mesially (17/33) orientated third molars. A retromolar foramen and canal were present in most mandibles, with more than half being bilateral. We were unable to confirm a potential relation between the retromolar foramen and canal on the one hand, and the orientation of the third molar on the other.