メカトロニクス・ロボティクスを用いたそしゃく時の下顎骨歪に関する研究

Abstract

The purpose of this study was to investigate the mechanical behavior of the human mandible in mastication for basic knowledge in order to understand the interrelationship between malocclusion and bone deformation.For reproduction of accurate mechanical conditions, mechanical mastication robotics with viscous-elastic actuator controlled by a 32-bit computer system was used. Dry skulls were placed on this robotics, and muscle loading direction, forces and attachment area were determined from the information of Computed Tomographic data of living subjects. The mechanical strain generated on the surface of mandibular bone during mastication was measured by three axial electric strain gages.The results were as follows:1) On the application of light loading forces (Totalamount of 24N), the mandibular bone was bent from the anterior to the posterior part in the gonial region. Only two-dimensional distribution of strain around the loading area was demonstrated.2) As for heavy force (Total 96N), a large amount of tension was generated from the anterior to the posterior part, the alveolar bone was inclined towards the lingual side, and inferior region of the rami was bent to the outside.From the results, three-dimensional changes of strain and dynamics during mastication were demonstrated. These findings suggested that various biomechanical situations occurred in the mandible during mastication, and skeletal growth and/or bone formation might be affected by the mechanical behavior of muscle loading.Therefore, the clinical diagnosis of dentomaxillofacial deformities should include careful consideration of the muscular performance and mechanical conditions.