A Pilot Study on the Estimation of Bite Force Using Electromyograms of the Masticatory Muscles.

It has not been established how electromyographic (EMG) data of masticatory muscles can estimate bite force (BF) during daily activities at home, such as eating and bruxism, utilising the EMG-BF correlation. This study aimed to investigate the relationship between actual BF and BF estimated using corresponding EMG data and additional information on BF and EMG measured on a separate day. Participants were 16 volunteers. The unilateral masseteric EMG was recorded during clenching tasks at 10 levels of force up to maximum voluntary clenching (MVC) twice on separate days (Day 1, Day 2). BF was simultaneously measured using a pressure-sensitive occlusal film. The regression equation between the BF and EMG amplitude was calculated on Day 1. Estimated BF on Day 2 was calculated using information on the EMG amplitude on Day 2 (EMG-amp), Day 1 BF at the MVC, and Day 1 regression equation. Actual value of BF showed a small correlation coefficient with EMG-amp, whereas strong correlations were observed with the estimated values additionally using information of Day 1 BF at the MVC. The estimated BF additionally using information of Day 1 regression equation adjusted by the ratio of EMG at the MVC on Day 1 to that of Day 2 showed the smallest error, indicating the power to estimate BF using corresponding EMG data became further improved. The obtained findings suggest the possibility of the clinical method estimating BF using corresponding EMG data with the additional information of EMG and BF on a separate day.