Komiyama Osamu, Wang Kelun, Svensson Peter, Arendt-Nielsen Lars, De Laat Antoon, Uchida Takashi, Kawara Misao
Department of Clinical Oral Physiology, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba 271-8587, Japan.
J Prosthodont Res. 2009 Apr;53(2):89-94. doi: 10.1016/j.jpor.2008.10.001. Epub 2008 Dec 30.
The purpose of this study was to characterize the relation between stimulus intensity, masseteric exteroceptive suppression (ES), and sensory perception as a possible quantitative or qualitative tool in the diagnosis of the masticatory system for prosthodontic treatment.
From 12 males and 12 females (22-41 years), surface EMG was recorded from the left masseter muscle. Visual feedback allowed the subjects to maintain a constant clenching level of 30% maximal voluntary contraction. Thirteen fixed stimulus intensities from 5 to 35 mA in 2.5 mA increments were applied at random. A computer program calculated the duration of ES, based on the 50% level of the mean pre-stimulus EMG. The stimulation intensity at which early (ES1) or late (ES2) exteroceptive suppressions appeared first and at which subjects answered as being painful were defined as the reflex threshold (RT1 or RT2) and pain threshold (PT), respectively. The relation between sensory perception and ES was evaluated using stimulus-response (S-R) curve analysis.
Significant differences were found between PT and RT1, and between RT1 and RT2 (P<0.001). After S-R curve analysis, the maximum duration of ES1 and ES2 was estimated at 9.6 ms and 33.5 ms, and appearance was rated as 6.2 and 4.0 on numeric rating scale (NRS), saturation was 7.6 and 6.9, and slope was 7.0 and 11.2, respectively.
All parameters for changes in ES following increasing incremental stimulus intensity could be analyzed. The construction of S-R curves in relation to sensory perception and ES parameters characterized the difference between ES1 and ES2.
本研究旨在描述刺激强度、咬肌外感受性抑制（ES）与感觉知觉之间的关系，作为一种可能的定量或定性工具，用于口腔修复治疗咀嚼系统的诊断。
选取12名男性和12名女性（年龄22 - 41岁），记录左侧咬肌的表面肌电图。视觉反馈使受试者保持30%最大自主收缩的恒定紧咬水平。以2.5 mA的增量随机施加13种固定刺激强度，范围从5 mA到35 mA。计算机程序根据刺激前肌电图平均值的50%水平计算ES的持续时间。早期（ES1）或晚期（ES2）外感受性抑制首次出现的刺激强度以及受试者回答有疼痛的刺激强度分别定义为反射阈值（RT1或RT2）和疼痛阈值（PT）。使用刺激 - 反应（S - R）曲线分析评估感觉知觉与ES之间的关系。
PT与RT1之间以及RT1与RT2之间存在显著差异（P<0.001）。经过S - R曲线分析，ES1和ES2的最大持续时间估计分别为9.6 ms和33.5 ms，在数字评分量表（NRS）上的出现评分为6.2和4.0，饱和度为7.6和6.9，斜率分别为7.0和11.2。
可以分析随着刺激强度增加ES变化的所有参数。与感觉知觉和ES参数相关的S - R曲线构建表征了ES1和ES2之间的差异。
