A Cone Beam Computed Tomography Analysis of Bone Volume Variations of Extra-alveolar Region Based on Sex, Age, Vertical and Sagittal Facial Patterns

Objectives: The goal of this study is to measure mandibular buccal shelf (MBS) concerning angulation, bone volume, and cortical bone volume as well as bone depth and cortical bone depth of infrazygomatic crest (IZC) via cone beam computed tomography and evaluate the measurements according to sex, age, vertical, and sagittal facial types. Materials and Methods: This study collected lateral cephalograms and cone beam computed tomography scans from 100 individuals, which were used to observe angulation, bone and cortical bone volume entailing width and depth of MBS as well as the depth of IZC. FH-MP (mandibular plane angle) and A point-Nasion-B point were adopted to determine vertical and sagittal facial patterns respectively. Results: Bone widths at 6 mm and 11 mm to cementoenamel junction (CEJ) and cortical bone width at 6 mm to CEJ in MBS showed significant sex differences, while bone depths and cortical bone depths in IZC show significant age difference( P <0.05). Bone width and cortical bone width at 6 mm to CEJ at the mesial root and 11 mm to CEJ at both roots as well as angulations of MBS in the mandibular first molar region, bone depth and cortical bone depth at the maxillary first molar distal buccal root, and the proximity region were all correlated to FH-MP ( P <0.05). Conclusions: Short-faced individuals of Asian ethnicity tend to have greater bone width, greater projection in MBS, and greater bone depth in the posterior region of IZC. The optimal implant sites are 11 mm apical to CEJ at the mandibular second molar distal root and 65° at the maxillary first molar mesial root.