Is Mandibular Third Molar's Angulation Associated with the Lingual Bone Thickness?

Abstract To find out whether the angulation of mandibular third molars is associated with the thickness of the bone at the site of impaction, and if so, which particular angulation affects the protective mechanism of the nerve, we retrospectively studied the thickness of lingual bone at the sites of impaction of 200 mandibular third molars in 149 patients using coronal, sagittal, and axial slices of cone-beam computed tomograms (CT). We measured the bone at the cementoenamel junction of the mandibular second molar, at the mid-root of the third molar, and at the apex of the root. Bone less than 1 mm thick was defined as “thinning”. We correlated these measurements with the angulation of the tooth based on the position of the second molar and the occlusal plane in 3 dimensions: vertical, mesiobuccal, and buccolingual. The primary outcome was the thickness of the bone around the third molar. A total of 102 teeth were on the left (51%), and 125 were angulated with an occlusal plane of