Relationships among facial type, buccolingual molar inclination, and cortical bone thickness of the mandible

The purpose of this study was to evaluate the relationships between differe nt facial types, and both the buccolingual molar inclination and cortical b one thickness of the mandible. The material consisted of 31 dry skulls of m odern Japanese males from the Museum of the University of Tokyo. They all d emonstrated normal occlusion with minimal dental discrepancy, and without c rossbite or facial asymmetry. The buccolingual inclination of the seco nd m olar (M2) in the long-faced subjects was significantly smaller than the sa me dimension in the average- and short-faced subjects. It was found that th e teeth of long-faced subjects were more lingually inclined than those of t he short-faced subjects. The cortical bone thickness of the first molar (M1 ) and M2 sections was thicker in short-faced subjects than in average- and long-faced subjects. The results of this study provide evidence that a sign ificant, but complex relationship exists between structures of the mandibul ar body and facial types. The morphological features that relate to mastica tory function and facial types are associated with the cortical bone thickn ess of the mandibular body, and the buccolingual inclination of the first a nd second molars.