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Structured Abstract Authors – Ueki K, Nakagawa K, Takatsuka S, Yamamoto E, Laskin DM Objective – To assess the relationship between skeletal morphology and stress direction on the temporomandibular joint (TMJ) by a two-dimensional rigid body spring model (RBSM). Design – Lateral cephalograms were analyzed and the information was processed with a fortran analysis program. Setting and Sample Population – The subjects were 149 patients (54 men and 95 women, mean age 21.8 ± 5.9 years) from Kanazawa University Hospital and the School of Dentistry, Virginia Commonwealth University. Of the 149 cases, 48 were skeletal class I, 54 were class II, and 47 were class III. The patients had no TMJ symptoms or abnormalities. Outcome Measure – The force vector on the condyle, its direction (Ph angle), the degree of the vector (Ph) and the displacement vector (u, v), and the rotational angle (θ) of the mandibular body were calculated by RBSM. Results – The direction of the force vector (Ph angle) on the condyle was 24.83°± 4.67° in the class II group, 21.04°± 5.59° in the class I group, and 19.58 ± 7.57° in the class III group. The Ph angle of the class II group was significantly larger than those of the class I and III groups (p |
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