抄録
This study aimed to evaluate the morphological characteristics of the infrazygomatic crest with various jaw morphologies, occlusal forces, and maxillary first molar position in three dimensions to explore various factors that affect the morphology of the infrazygomatic crest, and to obtain knowledge regarding the ideal maxillary first molar position. Seventy-three Japanese subjects （32males with a mean age of 22.50±6.23 years and 41 females with a mean age of 25.17±6.78 years） had their occlusal force measured and underwent cone-beam CT for orthodontic treatment. The subjects were categorized into the following three groups based on the mandibular plane angle （Mp）: hypodivergent group （Mp＜23°）, normodivergent group （Mp 23°‒30°）, and hyperdivergent group （Mp≥30°）. Subjects were also divided into two groups based on the maxillary first molar positions: mesial and distal. The thickness of the infrazygomatic crest was evaluated using cross-sectional cone-beam CT images obtained in the coronal and axial planes. The thickness of the infrazygomatic crest in the coronal plane significantly differed among the hypodivergent, normodivergent, and hyperdivergent groups and between the mesial and distal groups. The thickness of the infrazygomatic crest in the axial plane significantly differed among the hypodivergent, normodivergent, and hyperdivergent groups. In conclusion, differences in the maxillary first molar position and the vertical skeletal pattern may affect the morphology of the infrazygomatic crest.
