Three-Dimensional Cranio-Maxillary Measurements of the Mouse With Spontaneous Malocclusion Using the Micro-Computed Tomography

  • Dr Fumio Saito, Hokkaido University, Japan
  • Dr Takashi Kajii, Hokkaido University, Japan
  • Dr Yuki Sugawara-Kato, Hokkaido University, Japan
  • Dr Yuri Tsukamoto, Hokkaido University, Japan
  • Prof Yoshinori Arai, Nihon University, Japan
  • Prof Yoshifumi Hirabayashi, Nagoya Bunri University, Japan
  • Prof Osamu Fujimori, Nagoya Gakuin University, Japan
  • Prof Junichiro Iida, Hokkaido University, Japan

Objective: BALB/c-bm/bm mouse has various characteristics in which the most important feature is spontaneous malocclusion (incisal transverse crossbite). The objective of this study was to clarify the morphological characteristics of cranio-maxillary deviations in BALB/c-bm/bm mice using three-dimensional (3D) morphological measurements.
Methods: Female mice at ages of 13 and 25 weeks were divided into the following three groups: control group (BALB/c-+/+ mice), Norm group (BALB/c-bm/bm mice with normal occlusion), and Mal group (BALB/c-bm/bm mice with malocclusion). Six points in the skull were selected and distances between two points were measured using images of 3D micro-computed tomography (CT).
Results: At both ages, inter-group comparison showed that the lengths of almost all measurements in the Norm and Mal groups (both shift and non-shift sides) were significantly shorter than those in the control group. Intra-group comparison between the shift and non-shift sides in the Mal group showed that significant lateral deviation occurred at the maxilla and nasal bone.
Conclusions: Using 3D micro-CT images, this study quantitatively shows that the cranio-maxillary complex of BALB/c-bm/bm mice is significantly smaller than that of control mice and that BALB/c-bm/bm mice have spontaneous transverse crossbite due to lateral deviation of the maxilla and nasal bone.