Electromyographic evaluation of the effect of hard and soft stabilizing appliances on masseter and anterior temporalis muscles in asymptomatic individuals

Background/Aim: Stabilization appliances have traditionally been used for the treatment of temporomandibular disorders and bruxism. The aim of this study was to evaluate the effect of two appliances (hard and soft) with different thicknesses on the electromyographic (EMG) activities of masseter and anterior temporalis muscles. Material and Methods: 30 healthy subjects have been divided into two groups of 15, according to the appliance material used (soft, hard). For each subject in both groups, two appliances have been prepared with 3 mm and 6 mm thickness. EMG recordings of bilateral masseter and anterior temporalis muscles were taken for each appliance. Results: The results showed that, the decrease in average EMG values during maximum voluntary clenching with a 3-mm and 6-mm-thick hard appliance was statistically significant compared with the average EMG of maximum voluntary clenching in the intercuspal position. The increase in average EMG values during maximum voluntary clenching with a soft appliance of 3 mm and 6 mm thickness was statistically significant. Conclusions: The hard stabilization appliances decrease the activity of the masseter and temporalis muscles, while the soft appliances increase the activity of the masseter and temporalis muscles.