Standardised indexes reduce the variability of masticatory muscles electromyographic values

In dentistry, Surface Electromyography (sEMG) is currently used in both clinical and research fields to study the electrical activity of the masticatory muscles, such as the anterior Temporals and Masseters, which are easily accessible. Due to biological and technical factors that can alter the capture of the sEMG signal, comparing recordings obtained from the same subject at different days, with electrode replacement, can be challenging, thus complicating inter- and intra-subject sEMG comparisons. In the present study, sEMG activity of the masticatory muscles during maximum teeth clenching was simultaneously recorded using two different electrode configurations (A and B) to simulate different electrodes positioning as may occur between appointments. Raw sEMG signals and standardised indexes based on acquisitions from configurations A and B were compared. The position of the electrodes significantly affected the sEMG raw potentials of the masticatory muscles during maximum teeth clenching, while standardised indexes were not influenced by electrode positioning.