Morphometric analysis of prognathic and non-prognathic mandibles in relation to BSSO sites using CBCT

BACKGROUND: Bilateral sagittal split osteotomy (BSSO) is the most versatile procedure and adopted by many surgeons to relocate the mandible in patients having mandibular prognathism (MP). Injury to the inferior alveolar nerve (IAN) and unfavorable splits are two surgical complications of BSSO which are associated with mandibular morphology. Uses of cone beam computed tomography (CBCT) in providing 3-D images has gained a wider acceptance in surgical field nowadays. Its advantages are including reduced cost, lesser radiation dose and smaller physical footprint comparing to the conventional computed tomography.

PURPOSE: This study aims to identify the differences in morphology of prognathic and non-prognathic mandible at BSSO sites using cone beam computed tomography images.

METHODS: This retrospective study involved 51 CBCT images of patients having mandibular prognathism and without mandibular prognathism. The latter group made up from patients with Class I skeletal pattern. Samples were taken using purposive sampling method from two clinical centers.

RESULT: Prognathic mandible has higher lingula level, superiorly and buccally placed inferior alveolar nerve canal at distal second molar, thinner mediolateral width of ramus at anterior and posterior part and thinner anteroposterior width of the ramus.

CONCLUSION: Morphology of mandible in patients with mandibular prognathism (MP) was significantly different from patients without mandibular prognathism (WMP) for most of the parameters. The high risk parameters may be highlighted to the patients using cone beam computed tomography images.