Modulation of jaw movement patterns in response to different food textures during mastication in mice

This exploratory study aimed to explore the key determinants of characteristic masticatory movements in mice focusing on the amount of vertical and lateral gape associated with condylar movement on both sides depending on different food textures. Jaw movements with six degrees of freedom were measured by means of a motion capture system using 13 Jcl:ICR mice. Pellets, cheese, and bananas were tested, and the relationship between food texture and jaw movement patterns was investigated. The mice showed two unique jaw movement trajectories. That is, the opening and closing paths were wide apart in the sagittal plane, and the mandible deviated randomly to the right or left in the opening phase in the frontal plane. These tendencies became more pronounced with increased food hardness. As the food hardness increased, the grinding path at the occlusal phase was extended from the lateral view, and the amount of lateral gape at maximum jaw opening also increased. In this way, the grinding efficiency was considered to be improved when chewing harder food through modification of the jaw movement pattern.