Bilateral symmetry of the mastoid processes in jaw deformity cases with mandibular deviation

Abstract

We used three-dimensional computed tomography (3 D-CT) to investigate differences in the amount of mandibular deviation and the position of the mastoid processes at the insertion of the sternocleidomastoid muscle in subjects who had jaw deformities with mandibular deviation. We measured the distance from the Frankfort horizontal (FH), frontal and sagittal median planes to the mastoid processes. We also measured mandibular deviation as the distance from the sagittal median plane to Me (Me deviation distance), the angle of the FH plane to Ag line (vertical mandibular deviation angle), as well as the angle of the sagittal median plane to Ag line (axial mandibular deviation angle). We calculated the ratios of the vertical, anteroposterior and lateral distances from each plane to the bilateral mastoid processes.
     Significant correlation was found between the Me deviation distance and the ratio of the vertical distance to the bilateral mastoid processes. Significant correlation was also found between the aial mandibular deviation angle and the ratio of the vertical distance to the bilateral mastoid processes. 0ur results suggest that in patients with jaw deformities there is a correlation between deviation of the mandible from the body axis and the position of the mastoid processes.