ヒト下顎骨の個体別応力解析を目的とした咀嚼筋力推定 * *1 , *1 , *2 Estimation of Masticatory Forces for Patient-Specific Stress Analysis of the Human Mandible Michihiko KOSEKI *3 , Norio INOU and Koutaro MAKI *3 Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8550 Japan An individual evaluation of mechanical characteristics of a bone provides useful information for diagnoses and treatments of each patient. This paper proposes an estimation method of the masticatory forces using an objective function composed of three criteria: efficiency of muscular activities, moment balance between muscular and biting forces, and reaction forces at condyles. The method is firstly applied to a patient whose jaw has a severe deformity. After examination of effects of the criteria, patient- specific stress analyses are performed using the estimated muscular forces. The analytical result shows no stress concentration and little difference in stress distribution on both left and right sides in spite of the asymmetrical mandibular shape and masticatory condition. Then, the method is applied to another two patients with different mandibular morphologies. The estimated forces of the two patients well agree to the empirical knowledge of the relationship between mandibular shape and muscular forces. Key Words : Biomechanics, Computer aided analysis, Muscle and skeleton, Masticatory system, Estimation, Finite element method, Patient-specific model. 1. 緒 言 X CT MRI マル ライ モ ル (1)∼(4) モ ル レ モ ル ・ ・ ポイ モ リ (5)∼(7) 1 * 2004 11 18 17 2007 12 17 . *1 , (〒 152-8550 2-12-1). *2 (〒 145-0062 2-1-1). Email: [email protected]M Tp Ta Pl Pm (a) Masticatory muscles for stress analysis (b) Mechanical support condition M: Masseter Pm: Medial Pterygoid Pl: Lateral Pterygoid Ta: Anterior Temporalis Tp: Posterior Temporalis x, y, z fixed y , z fixed z fixed z y x Fig. 1 Mechanical conditions in occlusion. ポイ ヒ ヒ 1(a) 5 (M) (Pm) (Pl) (Ta) (Tp) 1
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ヒト下顎骨の個体別応力解析を目的とした咀嚼筋力推定 ∗
小関 道彦 ∗1, 伊能 教夫 ∗1, 槇 宏太郎 ∗2
Estimation of Masticatory Forces
for Patient-Specific Stress Analysis of the Human Mandible
Michihiko KOSEKI∗3, Norio INOU and Koutaro MAKI
∗3 Graduate School of Science and Engineering, Tokyo Institute of Technology,2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8550 Japan
An individual evaluation of mechanical characteristics of a bone provides usefulinformation for diagnoses and treatments of each patient. This paper proposes anestimation method of the masticatory forces using an objective function composed ofthree criteria: efficiency of muscular activities, moment balance between muscular andbiting forces, and reaction forces at condyles. The method is firstly applied to a patientwhose jaw has a severe deformity. After examination of effects of the criteria, patient-specific stress analyses are performed using the estimated muscular forces. The analyticalresult shows no stress concentration and little difference in stress distribution on bothleft and right sides in spite of the asymmetrical mandibular shape and masticatorycondition. Then, the method is applied to another two patients with different mandibularmorphologies. The estimated forces of the two patients well agree to the empiricalknowledge of the relationship between mandibular shape and muscular forces.
Key Words : Biomechanics, Computer aided analysis, Muscle and skeleton, Masticatory
system, Estimation, Finite element method, Patient-specific model.
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