Evaluation of localisation of mandibular foramen in patients with mandibular third molar teeth using cone-beam computed tomography.

BACKGROUND: It is important to know the correct anatomical location of the mandibular foramen to obtain successful anaesthesia of inferior alveolar nerve and to prevent injury to the mandibular vessels and nerve, during a variety of oral and maxillofacial surgical procedures. The aim of this study is to evaluate localisation of the mandibular foramen in patients with the third molars using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Cone-beam computed tomography was used to determine the location of the mandibular foramen in 67 patients (totally 99 sides) with unilateral or bilateral impacted mandibular third molars. RESULTS: The distance from the posterior border of the mandibular ramus to mandibular foramen did not differ significantly among the other angulations. But the difference between vertical and horizontal angulation of the impacted mandibular third molars according to 'fd' values (the shortest distance between mandibular foramen and the posterior border of mandibular ramus) was found to be statistically significant (p < 0.05). CONCLUSIONS: The present study provides new information to the literature concerning relationship between the location of the mandibular foramen and the mandibular third molars.

Ectopic Premolar Tooth in the Sigmoid Notch.

Impaction of a mandibular premolar is relatively uncommon. Ectopic placement is more unusual and there has been no discussion in the literature of an ectopic mandibular premolar in the coronoid process. In this case report, we present an impacted ectopic mandibular permanent premolar in the sigmoid notch (incisura mandibulae) region. Etiology of the tooth and treatment options are discussed and illustrated by Cone Beam Computed Tomography (CBCT) images.