CBCT location of the fusion between the buccal and lingual cortical in the mandibular ramus: importance to sagittal split osteotomy.

BACKGROUND: Mandibular Sagittal Split Osteotomy (MSSO) is a popular technique in orthognathic surgery used both to advance and to retreat the mandible. However, MSSO may incur in important complications, such as bad splits and sensorineural injuries. Knowing the location of the fusion between the buccal and lingual cortical (FBLC) in the mandibular ramus and the bone thickness in the region where osteotomies will be performed is determinant in MSSO planning to avoid complications. The aim of this study was to document and evaluate possible differences between sexes regarding the location of the FBLC in relation to the superior cortical of mandibular foramen (MF) and bone thickness in the region of interest for MSSO in a Brazilian population. MATERIAL AND METHODS: Eighty five cone-beam Computed Tomography (CBCT) scans were used to perform linear measurements to determine the location of the FBLC. Bone thickness from the mandibular canal (MC) to the cortical external surfaces and the diameter of the MC were measured at three different points: mandibular ramus (A), mandibular angle (B) and mesial of the second molar (C). RESULTS: The FBLC was located at a mean distance of 8.3 mm from the superior cortical of the MF in males and 8.1 mm in females. There was no difference between males and females regarding the mean bone thickness from the MC to the buccal external surface at all the points investigated (p>0.05). Bone thickness from the lingual external surface to the MC was bigger among females than males in regions B and C (p < 0.05). The diameter of the MC was bigger among males in regions B and C. CONCLUSION: Sexual dimorphism regarding mandibular bone thickness but not regarding the location of FBLC was present. This fundamental knowledge may assist to the panning of MSSO.

Radiographic assessment of impacted mandibular third molar sockets filled with composite xenogenic bone graft.

OBJECTIVES: The main purpose of this study was to evaluate the radiographic aspect of the healing of extraction sockets filled with a xenogenic graft material (Gent-tech). METHODS: Thirty-nine patients ranging in age from 15 years to 25 years with bilateral impacted mandibular molars were chosen based on bilateral mandibular similarities. After tooth extraction, the socket was filled with the graft. The opposite site was left to heal naturally and served as a control. The experimental and control sites were chosen randomly. Bone density and crest healing were evaluated on digital radiographs taken immediately, 2 months and 6 months after surgery. The respective pixels values obtained with the Digora software were compared statistically. RESULTS: The results showed a significant decrease in the distance from the cemento-enamel junction to the alveolar bone crest, but no difference was found between the control and experimental groups. Bone density increased significantly, and there was difference between experimental and control groups. CONCLUSION: The analysed parameters observed by the authors were similar to those of the control group, suggesting xenogenic graft being an acceptable material and a graft option.