International Comparative Study on Pain Cognition and Pain Sensitivity in the Orofacial Region

Research Project

Project/Area Number	13470413
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	補綴理工系歯学
Research Institution	OKAYAMA UNIVERSITY
Principal Investigator	YATANI Hirofumi Okayama Univ., Grad. schl. of Med. and Dent., Professor, 大学院・医歯学総合研究科, 教授 (80174530)
Co-Investigator(Kenkyū-buntansha)	MAEKAWA Kenji Okayama Univ., Grad. schl. of Med. and Dent., Assoc. Prof., 大学院・医歯学総合研究科, 講師 (20304313)
Project Period (FY)	2001 – 2002
Project Status	Completed (Fiscal Year 2002)
Budget Amount *help	¥9,200,000 (Direct Cost: ¥9,200,000) Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000) Fiscal Year 2001: ¥8,300,000 (Direct Cost: ¥8,300,000)
Keywords	Perception threshold / Pain threshold / gender difference / laterality / Hot stimulation / Cold stimulation / Current stimulation / CPT / 電流知覚閾値 / 三叉神経 / 正中神経 / 疼痛閾値 / 国際比較 / 侵害刺激 / 感情的反応 / 温熱刺激 / 電気刺激
Research Abstract	The purpose of this study was to compare of the pain threshold in the trigeminal nerve region between healthy male and female volunteers. 1. Measurements of current perception and pain thresholds in the trigeminal nerve region 1) The test-retest reliability of current perception threshold measurements Intra-class correlations for the trigeminal nerve following 2,000, 250, and 5 Hz stimulation were 0.62, 0.80, and 0.86, respectively. Reliability was therefore favorable for all three frequencies. 2) Gender differences of current perception and pain thresholds Irrespective of stimulation frequencies, the current perception threshold was significantly lower in females than in males, whereas the mean current pain threshold was lower, but not significant, in females than in males. 2. Measurements of thermal perception and pain thresholds in the trigeminal nerve region 1) Gender differences of perception threshold for hot and cold stimuli The mean perception thresholds for hot and cold stimuli were lower in females than in males but the gender differences were not significant. Since the p-values were slightly bigger than 0.05, it is anticipated the differences would be significant in bigger samples. 2) Gender differences of pain threshold for hot and cold stimuli There were no gender differences in pain threshold for hot and cold stimuli. These results suggest that, compared to healthy-males, healthy females are more sensitive to tactile or pressure sensations, and that the gender differences on the pain threshold with pain-related nerve fibers such as A δ and C fibers can be ignored. The gender difference of patient population with orofacial pain might be explained by not the peripheral mechanism, but the central mechanism of pain perception.