Frisardi G, Ravazzani P, Tognola G, Grandori F
Dipartimento di Neurofisologia del Dolore, Università La Sapienza, Roma, Italy.
J Oral Rehabil. 1997 Dec;24(12):920-8. doi: 10.1046/j.1365-2842.1997.00577.x.
This investigation is focused on the analysis of the masseter responses evoked by means of magnetic and electric stimulation of the cortex and root of the trigeminal system of 20 healthy subjects. Moreover, in order to determine jaw elevation in centric occlusion, the analysis also focused on the motor response of the trigeminal bilateral roots evoked simultaneously using two stimulators. The masseter responses show a high level of symmetry in both latency and amplitude. The difference between the hinge axis in natural centric occlusion (CO) and in centric relation (CR) as determined by electric and magnetic transcranial stimulation is lesser than 2.5 mm. This is due to two main factors: (i) the response is evoked from the trigeminal motor neural pool involving all the masticatory muscles and hence simulating the natural 'muscular coactivation'; (ii) there is no manual manipulation to guide the jaw into the centric relation (CR). This method could be of some help for diagnosis in patients suffering from TMJ dysfunction who have lost stereognostic control over the jaw and display obvious signs of deviation during closure of the mandible.
本研究聚焦于对20名健康受试者的三叉神经系统皮层及神经根进行磁刺激和电刺激所诱发的咬肌反应进行分析。此外，为确定正中咬合时的下颌抬高情况，该分析还着重于使用两个刺激器同时诱发的双侧三叉神经根的运动反应。咬肌反应在潜伏期和幅度方面均呈现出高度对称性。通过电刺激和磁刺激经颅刺激所确定的自然正中咬合（CO）和正中关系（CR）中的铰链轴之间的差异小于2.5毫米。这主要归因于两个因素：（i）反应是由涉及所有咀嚼肌的三叉神经运动神经池诱发的，因此模拟了自然的“肌肉共同激活”；（ii）没有手动操作来引导下颌进入正中关系（CR）。该方法对于患有颞下颌关节功能障碍且对下颌失去立体定向控制并在闭口时表现出明显偏斜迹象的患者的诊断可能会有所帮助。
