Does the bruxism ease the mental stress?

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11671932
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 補綴理工系歯学
• Research Institution: Okayama University
• Principal Investigator: NATSUAKI Nobukuni Okayama University, University Hospital of Dentistry, Research Associate, 歯学部・附属病院, 助手 (60294427)
• Co-Investigator(Kenkyū-buntansha): MINAGI Shogo Okayama University, Dental School, Associate Professor, 歯学部, 助教授 (80190693) ; NISHIGAWA Goro Okayama University, University Hospital of Dentistry, Assistant Professor, 歯学部・附属病院, 講師 (00172635)
• Project Period (FY): 1999 – 2000
• Keywords: bruxism / stress / hormone / EMG / urine / noradrenaline / sleep

Research Abstract

The purpose of this study was to examine the influence of the inhibition of the bruxism during sleep on the relationship between the EMG of the masseter and the concentration of the stress hormone in the urine.
Twelve subjects were selected in this study. The EMG of the masseter during sleep at night was recorded. Besides this recording, the urine was collected before sleeping and just after the rising. These practices were performed under the following three types of the condition. The first was the condition, which was free from the inhibition of the bruxism. The second was the conndition, which inhibit the bruxism using the appliance. The third was the condition, which was free from the inhibition of the bruxism using the dummy of the appliance. The number of the episode of the EMG burst per hour was computed in each of the three types of the condition. The urine hormone ratio (after rising/before sleep) was also calculated. The four hormones were examined in this study ( dopamine, noradrenaline, adrenaline). In each of the four hormones, the correlation between the number of the episode of the EMG burst and the urine hormone ratio was examined. If the correlation was observed in some kind of the hormone, then the correlation between the EMG and the urine hormone ratio was re-examined in that kind of hormone.
Noradrenaline indicated the high correlation between the EMG and the urine hormone ratio. On the contrary, other three kind of hormones indicated low correlation. Noradrenaline indicated high correlation between the EMG and the urine ratio under the two types of the condition, which was free from bruxism. On the contrary, noradrenaline indicated low correlation between the EMG and the urine ratio under the condition, which inhibit the bruxism.