Morphometric Analysis of Cleft Lip Palate and Prognathic Mandibles in Relation to Mandibular Canal Course

This study aimed to evaluate the mandibular canal course in individuals with cleft lip palate (CLP) and mandibular prognathism in terms of the sagittal split-ramus osteotomy using cone-beam computed tomography.

Individuals with CLP older than 16 years of age and planned to undergo Le fort I + SSR osteotomies and those with class III occlusion planned to undergo Le fort I + SSR osteotomies were included. The measurements on the cleft side of CLP patients were compared with both their noncleft sides and those with class III occlusion. The course of the inferior alveolar nerve and its position in the mandible were evaluated starting from the mandibular foramen, the first entrance to the mandible, to the mental foramen, the exit from the mandible.

The distance between the mandibular canal and the buccal surface of the mandible (B3) on the plane tangent to the distal of the mandibular first molar and perpendicular to the occlusal plane was found to be greater in individuals with CLP (P = 0.011). Buccal cortex thickness (C4) at the level of the mandibular canal on the plane tangent to the distal of the mandibular second molar and perpendicular to the occlusal plane was found to be lower in individuals with CLP (P = 0.021).

The buccal cortex thickness of the mandible corpus and the distance of the mandibular canal to the buccal surface is different in patients with CLP compared to class III individuals' posterior to the mandible. Surgeons should take these differences into consideration during mandibular osteotomy.