Influence of TMJ dysfunction on Bennett movement as recorded by a modified pantograph. Part III: Progress report on the clinical study.

The purpose of this investigation was to provide further insight into the characteristics of the induced and voluntary Bennett movement by determining the influence of TMJ dysfunction on the lateral side shift of the mandible as recorded by a modified pantograph. Twelve subjects were examined using pantographic tracings quantitated with the PRI to establish a baseline pattern of dysfunction for each subject. The PRI was used to categorize the subjects as to the degree of dysfunction. Following categorization, eight subjects were used as an experimental group and for subjects as a control group. On all subjects, induced and voluntary Bennett movement registrations were taken at the initial and final adjustment. Only the experimental subjects underwent an occlusal therapy consisting of an occlusal splint and an occlusal adjustment. Success of the therapy was monitored via the PRI. Following occlusal therapy, the reduction in PRI scores and categorization for the experimental group was significant to the 0.0042 level. There was no significant change inthe scores for the control group. Post-treatment Bennett movement registrations (voluntary and induced) indicated a statistically significant increase of the movement at the 0.043 level. The control group showed no significant change. Furthermore, on all subjects studied in this investigation, the voluntary Bennett movement was always within the borders of the induced Bennett movement, suggesting that the subject's neuromusculature was an important component in registering the lateral side shift of the mandible.