Gutiérrez Mario Felipe, Miralles Rodolfo, Fuentes Aler, Cavada Gabriel, Valenzuela Saúl, Santander Hugo, Fresno María Javiera
Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile, Santiago, Chile.
Cranio. 2010 Jan;28(1):43-9. doi: 10.1179/crn.2010.006.
The aim of this study was to determine the effect of tooth clenching and grinding on anterior temporalis electromyographic (EMG) activity. The sample included 30 healthy subjects with natural dentition and bilateral molar support, 15 with bilateral canine guidance and 15 with bilateral group function. An inclusion criterion was that subjects have to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left and right anterior temporalis muscles. EMG activity was recorded during the following conditions: A. eccentric grinding from intercuspal position to the right lateral edge-to-edge contact position; B. clenching in right edge-to-edge lateral contact position; and C. concentric grinding from right lateral edge-to-edge contact position to intercuspal position. On the working side, EMG activity was not significantly different between conditions in both occlusal schemes. On the nonworking side, EMG activity was significantly higher during condition C than condition B in both occlusal schemes (mixed model with unstructured covariance matrix). When comparing by side, EMG activity was significantly higher during conditions A and B on the working side than on the nonworking side. However, there was no significant difference during condition C. EMG activity was significantly lower with canine guidance than group function on the working side (in all conditions) as well as during concentric grinding on the nonworking side. These results could explain muscular symptoms in the anterior temporalis muscles if the subject is experiencing parafunctional habits either while awake and/or sleep that exceed the individual's adaptation capability.
本研究的目的是确定紧咬牙和磨牙对颞肌前束肌电图（EMG）活动的影响。样本包括30名具有天然牙列和双侧磨牙支持的健康受试者，其中15名具有双侧尖牙引导，15名具有双侧组功能。纳入标准是受试者必须没有咀嚼系统任何功能障碍的体征和症状。将双极表面电极置于左右颞肌前束上。在以下条件下记录EMG活动：A.从牙尖交错位向右侧边缘对边缘接触位的非正中磨牙；B.在右侧边缘对边缘侧方接触位紧咬牙；C.从右侧边缘对边缘接触位向牙尖交错位的正中磨牙。在工作侧，两种咬合模式下各条件之间的EMG活动无显著差异。在非工作侧，两种咬合模式下条件C期间的EMG活动均显著高于条件B（采用具有非结构化协方差矩阵的混合模型）。按侧别比较时，工作侧条件A和B期间的EMG活动显著高于非工作侧。然而，条件C期间无显著差异。在工作侧（所有条件下）以及非工作侧正中磨牙期间，尖牙引导时的EMG活动显著低于组功能时。如果受试者在清醒和/或睡眠期间经历了超过个体适应能力的副功能习惯，这些结果可以解释颞肌前束的肌肉症状。
