Association between nocturnal bruxism and gastroesophageal reflux.
OBJECTIVE
To examine the relationship between nocturnal bruxism and gastroesophageal reflux.


METHODS
Controlled descriptive study and double-blind, placebo-controlled, clinical study.


METHODS
Portable pH monitoring, electromyography, and audio-video recordings were conducted during the night in the subjects' home.


METHODS
Ten patients with bruxism and 10 normal subjects were matched for height, weight, age, and sex. They did not have symptoms of gastroesophageal reflux disease.


METHODS
Medication with a proton pump inhibitor (ie, a gastric-acid-inhibiting drug).


RESULTS
The bruxism group showed a significantly higher frequency of nocturnal rhythmic masticatory muscle activity (RMMA) episodes (mean +/- SD: 6.7 +/- 2.2 times per hour) and a higher frequency and percentage of time of gastroesophageal reflux episodes with a pH less than 4.0 and 5.0 (0.5 +/- 0.9 and 3.6 +/- 1.6 times per hour and 1.3% +/- 2.5% and 7.4% +/- 12.6%, respectively) than the control group (RMMA episodes: 2.4 +/- 0.9 times per hour; gastroesophageal reflux episodes: 0.0 +/- 0.0 and 0.1 +/- 0.3 times per hour and 0.0% +/- 0.0% and 0.0% +/- 0.0%, respectively). In the bruxism group, 100% of the gastroesophageal reflux episodes with a pH less than 3.0 and 4.0 included both an RMMA episode and an electromyographic burst, the duration of which was approximately 0.5 to 1.0 seconds, probably representing swallowing of saliva. The majority of gastroesophageal reflux episodes with a pH of 4.0 to 5.0 also included both an RMMA episode and an electromyographic burst in the control and bruxism groups (100% +/- 0.0% vs 70.7% +/- 16.5%), again probably due to swallowing of saliva. The remaining minority of gastroesophageal reflux episodes with a pH of 4.0 to 5.0 contained only an electromyographic burst (swallowing of saliva). The frequency of RMMA episodes after the release of the medication from the proton pump inhibitor, which increased the gastric and esophageal pH, was significantly lower than that after administration of the placebo in the control and bruxism groups (1.0 +/- 0.6 vs 1.9 +/- 3.2 times per hour, and 3.7 +/- 1.9 vs. 6.0 +/- 2.2 times per hour, respectively).


CONCLUSIONS
Nocturnal bruxism may be secondary to nocturnal gastroesophageal reflux, occurring via sleep arousal and often together with swallowing. The physiologic link between bruxism and the increase in salivation needs to be investigated.
Miyawaki
Shouichi
S
Department of Orthodontics and Dentofacial Orthopedics, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
Tanimoto
Yuko
Y
Araki
Yoshiko
Y
Katayama
Akira
A
Fujii
Akihito
A
Takano-Yamamoto
Teruko
T
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D000897:Anti-Ulcer Agents / Q000494:pharmacology / Q000627:therapeutic use; D001562:Benzimidazoles / Q000494:pharmacology / Q000627:therapeutic use; D002012:Bruxism / Q000150:complications*; D004576:Electromyography; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000188:drug therapy; D006801:Humans; D008297:Male; D008410:Masticatory Muscles / Q000502:physiology; D009853:Omeprazole / Q000031:analogs & derivatives; D054328:Proton Pump Inhibitors; D064750:Rabeprazole
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D001562:Benzimidazoles; D054328:Proton Pump Inhibitors; D064750:Rabeprazole; D009853:Omeprazole