1997 Volume 9 Issue 3 Pages 541-553
The purpose of this study was to investigate the morphologic changes in the mandibular condyle and craniofacial skeleton before and after orthodontic treatment for patients with osteoarthrosis (OA) of the temporomandibular joint (TMJ).
Ten joints of 6 patients (mean age; 17y 2m, range; 12y4m-20y7m) were examined by MRI and tomography before and after orthodontic treatment. The subjects were diagnosed as stage IV internal derangement of the TMJ according to Wilkes criteria, which denotes deformity and anterior displacement of the disk without reduction and severe resorption of the condyles. Osseous changes of the condyle were investigated in association with changes in condylar ratio and craniofacial morphology. The following findings were obtained.
1. After treatment, only one joint exhibited osseous change from “erosion” to “osteophyte”, whereas no changes were observed in the remaining joints.
2. Ratio of condylar height to the ramus height (condylar ratio), evaluated on panoramic radiographs, decreased in eight joints out of ten joints.
3. During orthodontic treatment, slight clockwise rotation and the subsequent retrusion of the mandible were found, although posttreatment results were acceptable and the vertical alveolar Night at the posterior region was well maintained.
The present results suggested that patients with OA of the TMJ may have a possibility of progress in condylar resorption during orthodontic treatment. Therefore, these patients should be managed carefully during orthodontic treatment with special attention to mandibular rotation and retrusion, which may be relevant to progressive resorption of the condyle.
