Xerox copy of the dental cast for analysis of the stability of mandibular osteotomy.
Stability of the mandible was analysed with a Xerox copy of the dental cast in 35 cases of mandibular prognathism corrected by ramus osteotomies. The occlusal relationship in the Xerox copy was illustrated by superimposing two contact points on the upper and lower dental arches and the change in the position of the lower dental arch in relation to the upper dental arch was obtained by superimposing the latter on preoperative, predicted postoperative, and six months postoperative occlusions. The stability of the mandible was analysed by measuring the movement of five landmarks (two posterior, two molar and one incisor points) set around the lower dental arch to represent the movement of the mandible. The relapse was estimated by the movements of the landmarks from the predicted postoperative occlusion to the six months postoperative occlusion. The mean estimated anterior relapses at the posterior and molar points with the larger predicted movement and the incisor point were between 0.9 mm. and 2.0 mm. at six months postoperatively, whereas on the side with the smaller predicted movement, the points moved posteriorly by 0.6 mm. and 0.5 mm. Despite the fact that the amount of the predicted lateral movement was much smaller than that of the predicted posterior movement at operation, the posterior points were estimated to relapse laterally by 2.0 mm. and 1.7 mm.(ABSTRACT TRUNCATED AT 250 WORDS)
Ueda
K
K
First Dept. of Oral and Maxillofacial Surgery, School of Dentistry, Niigata University, Japan.
Kobayashi
T
T
Nakajima
T
T
Sasakura
H
H
Hanada
K
K
D002508:Cephalometry; D003308:Copying Processes; D003724:Dental Arch / Q000033:anatomy & histology; D005544:Forecasting; D006801:Humans; D008334:Mandible / Q000033:anatomy & histology* / Q000601:surgery; D003765:Models, Dental; D010027:Osteotomy / Q000379:methods*; D011378:Prognathism / Q000473:pathology / Q000601:surgery*; D012008:Recurrence