Department of Prosthetic Dentistry, Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto 1-7-1, Nagasaki, 852-8501, Japan.
Department of Oral Health Sciences, KU Leuven, Leuven, Belgium.
Odontology. 2021 Jan;109(1):29-40. doi: 10.1007/s10266-020-00516-w. Epub 2020 Apr 9.
To examine the effect of preloading eccentric exercise on pain sensitivity in healthy volunteers.
In 20 healthy volunteers, pain-related sensations (6 items: pain, unpleasantness, fatigue, stiffness, tension, and soreness during maximum biting), and pain intensities induced by repeated electrical stimuli on the masseter and the hand palm were evaluated using a visual analog scale (VAS) of 0-100 mm. Eccentric exercise (6 min-test) or gum chewing (6 min-control) was used as preloading exercise to evaluate the effect on pain sensitivities before and after low-level clenching (15 min) performed 2 days after the preloading exercise.
Eccentric exercise induced only low levels of pain-related sensations 2 days later. However, the time course of temporal summation induced by four repeated electrical stimuli on the masseter was influenced by the type of preloading exercise, i.e., temporal summation increased after the low-level clenching (P = 0.016) when preloading was done by the eccentric exercise, while no significant change was observed when preloading was done by the gum chewing.
Eccentric exercise may facilitate pain sensitivity induced by subsequent low-level clenching via the central nervous system. In addition, it was demonstrated that pain sensitivity after the low-level clenching could be influenced by the type of preloading exercise. These experimental results may suggest that eccentric exercise could act as one of the triggering factors in the mechanism by which tooth clenching leads to a chronic pain condition in susceptible individuals.
探讨预载偏心运动对健康志愿者痛觉敏感性的影响。
20 名健康志愿者采用视觉模拟评分法（VAS）评估 6 项痛觉相关感觉（最大咬牙时的疼痛、不适、疲劳、僵硬、紧张和酸痛）和咬肌及手掌反复电刺激引起的疼痛强度（0-100mm）。偏心运动（6min-测试）或咀嚼口香糖（6min-对照）作为预加载运动，在预加载运动 2 天后进行低水平咬牙（15min）之前和之后评估对疼痛敏感性的影响。
偏心运动仅在 2 天后引起低水平的痛觉相关感觉。然而，咬肌上 4 次重复电刺激引起的时间总和的时程受预加载运动类型的影响，即偏心运动预加载后，低水平咬牙后时间总和增加（P=0.016），而咀嚼口香糖预加载后则无明显变化。
偏心运动可能通过中枢神经系统促进随后低水平咬牙引起的痛觉敏感性。此外，还表明低水平咬牙后的疼痛敏感性可能受预加载运动类型的影响。这些实验结果可能表明，偏心运动可能是咬牙导致易感个体慢性疼痛状态的机制中的触发因素之一。
