Objectives:

A randomized clinical trial comparing the effects of a 4- and 8-week consecutive use of contingent electrical stimulation on self-reported pain, jaw muscle activity, and threshold intensity in teeth grinding during sleep, over 6 months.

Methods:

This randomized clinical trial studied 48 patients diagnosed with bruxism and masticatory myofascial pain according to established methods. Patients were randomly allocated to Group I - 4-week contingent electrical stimulation (n=24), and Group II - 8-week contingent electrical stimulation (n=24). The primary outcomes assessed were the number of electromyographic events per hour of sleep, numerical rating scale pain scores, and threshold intensity when grinding. Analysis of variance models was used to compare results at a 5% significance level.

Results:

There was a statistically significant (p<0.05) decrease in pain level (-71.7% and -71.2%, respectively) and grinding mean intensity (-37.4% and -44.9%, respectively) at the 6-month follow-up for Group I. Contingent electrical stimulation reduced pain and the threshold intensity of grinding at night in patients with masticatory myofascial pain with definitive sleep bruxism, with a positive correlation (p<0.05) between the two primary outcomes.

Conclusions:

The results of this study suggest that both the 4- and 8-week contingent electrical stimulation protocols are effective in reducing patient symptoms related to sleep bruxism.

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