Immediate effect of an elastomeric oral appliance on the neuromuscular coordination of masticatory muscles : a pilot study in healthy subjects

To compare the electromyographic characteristics of masticatory muscles with and without a new elastomeric oral device proposed for masticatory muscle training, 10 healthy subjects aged 23 to 32 were examined. Surface electromyography of masseter and temporal muscles was performed during maximum teeth clenching without and with the device and during unilateral chewing with either gum or the device. During clenching, a significant increment of the overall muscular activity was promoted by the occlusal device in comparison with the intercuspal teeth clenching (P=0·05). Muscular standardised activity during device chewing was significantly higher than that during gum chewing (P=0·005), and it was more evenly distributed between working and balancing sides (P=0·023 right side, P=0·039 left side), and between masseter and temporal muscles (right side test, P=0·014). No significant differences were found for the global neuromuscular co-ordination, the masticatory symmetry and the chewing frequency. Clenching and chewing with the analysed occlusal prostheses was performed with a relative increment of muscular activity. These findings may be the basis for the training effect proposed for this device.