| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Research Abstract |
Bone has a structure adapted to the mechanical environment (Wolff's law). However, the complexity of both physical and biological conditions applied to bone have prevented us from investigating the mechanism as to how bone structure can provide enough durability to multiple loading conditions. To challenge this problem, we performed a comparison of the internal structure of human mandible with those structures generated by a simulated bone remodeling method that we used successfully in a previous study to reproduce the 2-dimensional structure of the human femoral neck (Tezuka, K et al., 2005, J Bone Miner Metabol 23, 1-7). A 3-dimensional mandible bone model consisting of approximately 1.5 million elements was constructed from sequential computer tomography (CT) images of a 14-year-old female with a bone cyst. The locations and directions of muscles, and their forces were predicted from the CT images. We emulated various biting conditions, such as incisor, left/right group (LG+RG), or left/right molar (LM+RM) biting, by restricting the movement of the corresponding teeth in angled planes. Finite element method (FEM) analysis and remodeling simulation were performed one after the other, and repeated until the internal structure adapted to each loading condition was obtained. As a result, the LM+RM biting condition generated structures showing the highest degree of similarity with the real mandible. However, structures generated by other conditions also showed significant similarity with that of real mandible, suggesting that the structure of mandible has been formed to provide enough durability to various biting conditions. The precise mechanism as to how the bone cells combine the input from various conditions and generate a single structure with durability to varying mechanical environment is still unknown, however, computer-aided methodology will be a powerful tool to give us further insight into such complex problems.
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