Real time evaluation of awake bruxism behaviors in young asymptomatic students and its impact on the masticatory muscles.

STATEMENT OF PROBLEM: The relationship of awake bruxism with pain is still unclear.

PURPOSE: The purpose of this clinical study was to evaluate awake bruxism behavior for 1 week in healthy young adults with ecological momentary assessment, assess its relationship with masticatory muscle tenderness, and the participation of endogenous analgesia.

MATERIAL AND METHODS: A total of 150 healthy participants were provided with a smartphone application that sent 10 alerts at random intervals every day. The participants were instructed to report in real time which of the following awake bruxism behaviors best represented their current condition: relaxed jaw muscles, tooth contact, tooth clenching, tooth grinding, or jaw bracing. At baseline, participants underwent recordings of the pressure pain threshold and conditioned pain modulation of the masticatory muscles. Pressure pain threshold recording was also repeated on the last day of the study. A t test was used to compare the first and the last pressure pain threshold recording after 1 week with an ecological momentary assessment evaluation. The Pearson correlation test was performed to evaluate the correlation between variables (α=.05).

RESULTS: Overall compliance was 75.9%. The average frequency of relaxed jaw muscles was 54.5%, tooth contact 29.4%, jaw bracing 5.8%, tooth clenching 9.7%, and tooth grinding 0.6%. The average frequency of a distinct awake bruxism behavior was 45.5%. A statistically significant increase in pressure pain threshold values was found (P=.001; P=.001; P=.045 for right and left anterior temporalis and left masseter, respectively). No significant correlation was found between the frequency of awake bruxism behaviors, the pressure pain threshold, and conditioned pain modulation (P>.05).

CONCLUSIONS: The most prevalent behavior was tooth contact (29.4%). No relationship was found between awake bruxism behaviors and masticatory muscle tenderness or endogenous analgesia.