Biofeedback experiments with a submaximal jaw closing force

Abstract

Temporomandibular disorders are often accompanied with pain in the elevator muscles such as Mm. Masseterici and Mm. Temporales. In most experiments measurement of the closing force of these muscles was conducted with maximum bite force using EMG-devices. The experiments presented here were conducted using visual or audible biofeedback using force transducers. Visual feedback was presented on a computer screen using geometrical graphics. Audible feedback used two different signals, the frequency of these audio signals was modulated. The force was chosen between 5 and 30 N, which is near the forces actually used for chewing, but far less than maximum clenching force. The persons chosen for the experiments were divided into two groups: A group of younger persons did not wear any removable dentures, a group of older persons was wearing a total prosthesis of the upper and lower jaw. The results were processed statistically and graphically. The goal for the persons conducting the experiments was to select a closing force as near as possible to the given force which was shown using the biofeedback. The actual force used by the person was also shown. There were no statistically significant differences in the results using 5, 10 or 30 N as given force. Results showed that older edentulous patients can modulate the chewing force not as exactly as younger persons. Especially when using low closing forces (5 N) the edentulous persons showed less exactness in reaching the given closing force. The results of the experiments may be used to develop a test to determine the capability of older patients to perform exact closing (and chewing) movements.