Abstract
It has been said that long-term denture wearers often undergo facial changes as a result of not only occlusal wear of the dentures and residual ridge resorption but also masticatory dysfunction. However, there are no references regarding analysis of morphological change in relation to the functional masticatory muscle activity which is fundamental to an understanding of maxillomandibular relation.
The purpose of this study was to investigate whether or not a method of mandibular repositioning that changes the facial skeletal structure can correct mandibular dysfunction. Sixty patients were examined who required denture renewal. Diagnosis of these patients was made, and a clinical method, following standardized treatment, was determined for obtaining correct mandibular position. Patients were evaluated before and after treatment using lateral and P-A cephalogram, transcranial TMJ radiograph, and EMG for bilateral coordination patterns of masticatory muscles.
The results were as follows:
1. In long-term use of complete dentures, there was a loss of occlusal vertical dimension and the mandible rotated counterclockwisely resulting in an increase in relative prognathism.
2. Loss of occlusal vertical dimension coupled with a habitually protruded mandible was corrected by sufficient clinical procedure to correct jaw relation.
3. Mandibular function could not be achieved without correction of the facial skeletal structure.
