Temporal bone pneumatization in patients with dentofacial deformities: cone beam computed tomography study.

Pneumatization in the osseous components of the temporomandibular joint (TMJ) may represent a complicating factor in TMJ surgery. This study determined the prevalence and characteristics of pneumatized articular eminence (PAE) and pneumatized glenoid fossa (PGF) using cone beam computed tomography (CBCT) scans of patients with and without dentofacial deformities. The CBCT of 587 asymptomatic patients (216 class I, 179 class II, 192 class III) were assessed to determine PAE and PGF. Age, sex, laterality, and type (uni/multilocular) of pneumatization were recorded. Differences were tested using the χ2 test and binary logistic regression models (P<0.05). Overall, 63.7% of patients presented some pneumatization: 15.5% presented both PAE and PGF, 0.9% presented only PAE, and 47.4% presented only PGF. The multilocular type was more frequent in both PAE and PGF (P<0.001). There was a significant difference regarding dentofacial deformity for PAE (P=0.021), with a higher frequency in class I. There were no differences according to sex, age, or laterality. The absence or lower frequency of pneumatization in class II and III patients may indicate continuous remodelling of the joint, which is submitted to abnormal occlusion forces. This knowledge is helpful for TMJ surgery planning, particularly as patients with dentofacial abnormalities may more often be candidates for TMJ surgery.

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.