Three-dimensional craniomaxillary characteristics of the mouse with spontaneous malocclusion using micro-computed tomography.

The aim of this study was to clarify the morphological characteristics of craniomaxillary deviations in BALB/c-bm/bm mice with a spontaneous malocclusion (incisal transverse crossbite) using three-dimensional (3D) morphological measurements. Sixty female mice aged 13 and 25 weeks were divided into the following groups: control (BALB/c-+/+ mice, n = 20), norm (BALB/c-bm/bm mice with a normal occlusion, n = 20), and mal (BALB/c-bm/bm mice with a malocclusion, n = 20). Various points in the skull were selected and the distances between two points were measured using 3D micro-computed tomography (CT) images. Statistically significant differences in measurement values among the three groups were evaluated by one-way analysis of variance with a probability level of P < 0.05 considered statistically significant. At both ages, the lengths of almost all measurements in the norm and mal groups were significantly shorter than those in the control group. Comparison between the shifted and non-shifted sides in the mal group showed that significant lateral deviation at the maxilla and nasal bone had occurred. Using 3D micro-CT images, the results of this study quantitatively showed that the craniomaxillary complex of BALB/c-bm/bm mice was significantly smaller than that of BALB/c-+/+ mice and that BALB/c-bm/bm mice have a spontaneous transverse crossbite due to lateral deviation of the maxilla and nasal bone.