Iida T, Overgaard A, Komiyama O, Weibull A, Baad-Hansen L, Kawara M, Sundgren P C, List T, Svensson P
Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Matsudo, Japan; Section of Clinical Oral Physiology, Department of Dentistry, Aarhus University, Aarhus, Denmark.
J Oral Rehabil. 2014 Feb;41(2):93-100. doi: 10.1111/joor.12128. Epub 2014 Jan 7.
In electromyographic (EMG) and functional magnetic resonance imaging (fMRI) studies, muscle and brain activity was compared during low levels of tooth clenching using a novel biting device to control bite force. A total of 21 healthy subjects performed motor tasks, comprising tooth clenching at 5, 10 and 20 N. During all measurements, subjects kept the novel bite device between the anterior teeth during tooth clenching. The EMG study (n = 15) characterised jaw muscle activity for the three motor tasks and demonstrated significant differences in root mean square (RMS) EMG amplitude between 5-, 10- and 20-N tooth clenching (F = 46.21, P < 0.001). There were no differences in variability of muscle activity between the three tooth-clenching levels. In an fMRI pilot study (n = 6), statistical comparisons were used to identify brain regions with significant activation in the subtraction of baseline from 5- or 20-N tooth-clenching activity. 5- and 20-N tooth clenching significantly and bilaterally activated the sensorimotor cortex, supplementary motor area, cerebellum and basal ganglia (P < 0.05, corrected for multiple comparisons). However, activation of each brain region did not differ significantly between two tooth-clenching tasks. Based on these preliminary findings, we propose that the novel biting device may be useful in further fMRI studies on controlled jaw muscle activation patterns in different craniofacial pain conditions. In addition, our fMRI result suggests that there are no significant differences in brain activity within low levels of tooth clenching with controlled force.
在肌电图（EMG）和功能磁共振成像（fMRI）研究中，使用一种新型咬合力控制装置，比较了在轻度紧咬牙时肌肉和大脑的活动。共有21名健康受试者执行运动任务，包括以5 N、10 N和20 N的力紧咬牙。在所有测量过程中，受试者在紧咬牙时将新型咬合力控制装置置于前牙之间。EMG研究（n = 15）对这三项运动任务的颌面部肌肉活动进行了特征分析，并显示在5 N、10 N和20 N紧咬牙时均方根（RMS）EMG振幅存在显著差异（F = 46.21，P < 0.001）。在三种紧咬牙水平之间，肌肉活动的变异性没有差异。在一项fMRI预试验研究（n = 6）中，通过统计比较来确定在从5 N或20 N紧咬牙活动中减去基线时具有显著激活的脑区。5 N和20 N紧咬牙均显著且双侧激活了感觉运动皮层、辅助运动区、小脑和基底神经节（P < 0.05，经多重比较校正）。然而，在两项紧咬牙任务之间，每个脑区的激活没有显著差异。基于这些初步发现，我们认为这种新型咬合力控制装置可能有助于进一步开展fMRI研究，以探究不同颅面部疼痛状况下控制颌面部肌肉激活模式。此外，我们的fMRI结果表明，在控制咬合力的轻度紧咬牙水平下，大脑活动没有显著差异。
