Stress release on mastication

• Project/Area Number: 17592042
• 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: Tokyo Dental College
• Principal Investigator: SAKURAI K. Tokyo Dental College, Dept.of Dentistry, Professor, 歯学部, 教授 (20153950)
• Co-Investigator(Kenkyū-buntansha): TAKAGI I. Tokyo Dental College, Dept.of Dentistry, Assistant Professor, 歯学部, 助手 (70349538) ; TAHARA Y. Tokyo Dental College, Dept.of Dentistry, Assistant Professor, 歯学部, 助手 (50385150) ; 石井 治仲 東京歯科大学, 歯学部, 助手 (00366171)
• Project Period (FY): 2005 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥3,000,000 (Direct Cost: ¥3,000,000); Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000); Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
• Keywords: mastication / stress / salivary cortisol / mental sweating / skin blood flow

Research Abstract

The purpose of this study was to clarify the effect of limited chewing side on stress release.
As stress loading, the subjects were required to perform mental calculation. They were required to chew for 10 min during stress loading. Chewing conditions were set to without, with habitual (non-limited chewing side) and with unilateral (limited chewing side preference) chewing. Salivary cortisol levels, mental sweating of thumb and skin blood flow of index finger were measured to evaluate stress level.
Change in mental sweating between before and during chewing showed a significant increase with unilateral chewing. There was a significant difference between without and with unilateral chewing, with the increase in mental sweating with unilateral chewing being greater than that without chewing. However, change in skin blood flow and salivary cortisol levels showed no significant differences among the 3 chewing conditions. Change in salivary cortisol levels between after stress loading and after 10 min rest from stress loading showed a significant reduction with habitual chewing. There were a significant difference between without and with habitual chewing, with habitual and with unilateral chewing.
This study showed that there were a significant difference in stress release between with habitual chewing and with unilateral chewing, and suggesting that habitual chewing is effective in stress release. No significant difference was observed in stress release between without and with unilateral chewing. Sympathetic hyperactivity with unilateral chewing showed to be greater than that without chewing.
This suggests that activity of sympathetic nerve and endocrine system is increased by chewing on limited chewing side and non-chewing side preference.