Abstract
The purpose of this study was to investigate long-term dentofacial stability after two-jaw orthognathic surgery in skeletal Class III malocclusion. Fourteen subjects, 12 females and 2 males, who had undergone two-jaw surgery at Tohoku University Dental Hospital were used in this study. Each patient had at least a five-year of post operative observation period. The frontal and lateral cephalometric radiographs were used for quantitative evaluation of dentofacial stability. The materials were taken seven times from the initial examination for 5 years postoperatively.
The results of this study were as follows:
1. Excellent postoperative stability was observed at the maxilla three-dimentionally.
2. Although antero-posterior displacement of the manbible after debonding was minimal, moderate relapse tendencies were observed vertically. Especially, significant reduction of lower facial height and Go to Or distance caused relapse in some patients.
3. Appropriate overjet has been maintained in most of the cases. But there was a tendency to decrease in overbite during the long-term observation period. However, none of the patients showed reversed occlusion or openbite at the latest examinations.
In conclusion, the results of this study indicated the following conditions to maintain long-term dentofacial stadibility after two-jaw surgery; 1) to establish a treatment planning to prevent vertical relapse of the mandible, 2) if necessary, to reconstruct the physiological occlusion by prosthetic treatment, and 3) to activate organs and tissues associated with the masticatory system by means of functional therapy and training.
