MRI of TMJ in patients with severe skeletal malocclusion following surgical/orthodontic treatment.

The aim of this study was to evaluate temporomandibular joints (TMJ) by magnetic resonance imaging (MRI) in patients who had undergone surgical/orthodontic or orthodontic treatment in a three-year follow-up study. Subjects consisted of 20 patients (40 TMJ), 16 females and four males (mean age 33.7 years, range 19-53 years), with severe temporomandibular disorders (TMD) referred to the Oral and Maxillofacial Department at Oulu University Hospital due to skeletal jaw discrepancy. All patients underwent extensive surgical/orthodontic or orthodontic treatment between 1996 and 2003. Clinical stomatognathic examination and MRI examinations were performed before the surgical/orthodontic or orthodontic treatment and one year after the completion of the treatment. The average treatment time was 23 months (range 12-34 months). MRI revealed a marked decrease, especially in the number of TMJ with joint effusion after the treatment. There were only a few changes in the number of diagnosed disk dislocations before and after the treatment. In five joints with anterior disk dislocation with reduction (r-ADD), a change to anterior disk dislocation without reduction (nr-ADD) was found. In 25 of the 40 condyles, the condylar configuration was normal on MRI before the treatment and in 19 condyles one year after the treatment. TMD signs and symptoms according to the Helkimo dysfunction index showed a statistically significant decrease after the treatment.