Association between Sleep Bruxism and Gastroesophageal Reflux

Objective: Sleep bruxism, defined as a stereotyped movement disorder or parasomnia, often causes abnormal tooth wear, masticatory muscle discomfort, and/or pain. Recently, several common features have been found separately on sleep bruxism and gastroesophageal reflux. The purpose of this study was to investigate the relationship between sleep bruxism and this reflux. Methods: Eight bruxism patients and 8 age- and sex- matched normal subjects participated in this study. Firstly, we measured the masticatory muscle activity (EMG), orofacial movements, and pH in the lower esophagus during sleep. Using the EMG and audiovisual data, we then scored bruxism episodes according to the research criteria of Lavigne et al. Acid reflux episodes were automatically scored. Secondly, we performed a randomized double-blind test to examine the effect of a secretory inhibitor of peptic regurgitation on sleep bruxism. The mean difference between groups was statistically analyzed. Results: Bruxism patients with a longer duration and higher frequency of bruxism episodes showed a significantly longer duration of acid reflux episodes than the normal subjects. The majority of bruxism episodes in all subjects occurred when the esophageal pH had decreased due to acid reflux. The frequency and duration of bruxism episodes after medication with a secretory inhibitor of peptic regurgitation were significantly lower and shorter, respectively, than those with the placebo medication. In fact, both parameters showed normal values after the secretory inhibitor of peptic regurgitation had been given. Conclusion: The results suggest that the occurrence of sleep bruxism is closely associated with acid reflux.