@article{oai:kanazawa-u.repo.nii.ac.jp:00026619,
 author = {Ueki, Koichiro and Nakagawa, Kiyomasa and Takatsuka, Shigeyuki and Yamamoto, Etsuhide},
 issue = {5},
 journal = {European Journal of Orthodontics},
 month = {Oct},
 note = {The rigid-body spring model (RBSM) theory was incorporated into a model as a discrete method for analysing problems of limit, such as the stress distribution on the condyle. The purpose of this study was to evaluate the two-dimensional RBSM for determining stress on the temporomandibular joint (TMJ) in patients after orthognathic surgery. Thirty-two patients (five males and 27 females, mean age 21.4 ± 4.9 years) with mandibular prognathism underwent bilateral sagittal split ramus osteotomy (SSRO) and setback; 48 subjects were recruited as controls. Anatomical landmarks were traced from pre- and post-operative lateral cephalograms and the information was processed using the Fortran analysis program. The force vector on the condyle, its degree, its direction, and the displacement co-ordinates (x, y) and rotation (θ) at the gonial angle were calculated. When muscular power was assumed to be 1, the post-operative degree of the force vector was higher than the pre-operative value (P < 0.05). The X co-ordinate, x, and rotation, q, of the displacement vector in the pre-operative patients with mandibular prognathism were significantly higher than those in the control subjects (P < 0.05). There were still significant differences between the displacement values post-operatively between the patients and controls (P < 0.05). The results suggest that the degree and direction of the force vector and the resulting displacement co-ordinates can be used as parameters in a surgical model. The RBSM may also be useful in evaluating the pre- and post-operative skeletal morphology of jaw deformities. © The Author 2006. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved., 金沢大学医学部附属病院歯科口腔外科},
 pages = {433--439},
 title = {The change of stress distribution on the condyle after mandibular setback surgery},
 volume = {28},
 year = {2006}
}