Relationship between facial types and tooth and bone characteristics of the mandible obtained by CT scanning

The purpose of this study was to evaluate relationships between morphological characteristics of vertical sections of the mandibular body and facial type. Of the correlation coefficients between tooth and bone inclination and facial type parameters, facial height index (FHI) was negatively associated with second premolar (P2), first molar (M1), and second molar (M2) inclinations. The angle represented by Frankfort horizontal plane to mandibular plane (FMA) was negatively associated with bone inclination of the M2 section. The buccal cortical bone was thicker in short-faced individuals than in the average and long-faced groups, while lingual cortical bone thickness of the M1 and M2 sections was greater. The basal cortical bone thickness of the L1 section was greater in the short-faced group, and the inclinations of the P2, M1, and M2 axes were significantly smaller. Teeth in the short-faced group inclined more lingually than in the average- and long-faced groups. The results of this study provide evidence that a significant but complex relationship exists between structures of the mandibular body and facial types. The morphological features that relate to masticatory function and facial types are associated with cortical bone thickness of the mandibular body and the buccolingual inclination of the first and second molars.