Image-based estimation of biomechanical relationship between masticatory muscle activities and mandibular movement

Current techniques for investigating the functional roles of masticatory muscles are not suited to explaining subject-specific biomechanical relationship between mandibular movements and masticatory muscle activities. The aims of this study were to estimate the muscle tensions of subject-specific masticatory muscles in dental occlusion through the three-dimensional morphologic changes (3DMCs) of the muscles, and to explain the subject-specific biomechanical relationship between the mandibular movement and the muscle tensions. One healthy adult subject underwent magnetic resonance (MR) scans of the head at mandibular rest position (M0) and maximum intercuspation (M1). Based on the two sets of MR images, the mandibular movement was measured by the position changes of the mental protuberance of the mandible and the muscle tension from M0 to M1 for each masticatory muscle was estimated by its 3DMCs. The results showed the subject-specific biomechanical relationship between the mandibular movement and the muscle tensions, and the mandibular movement could be explained by these related muscle tensions anatomically and functionally.