The analyses of Extraordinary Excitability or Pain in the Jaw and Neck Muscles due to the Pulpal and/or Periodontal Diseases

患有牙髓和/或牙周病的患者有时会观察到颈部和/或颌部肌肉疼痛。有理由认为这些症状是由肌肉的异常兴奋性引起的。本研究的目的是阐明肌肉疼痛的机制。在一项临床研究中，分析了受试者颈部和颌部肌肉的肌电，在一项基础研究中，在动物实验中研究了导致这些症状的神经生理机制。研究结果如下：1.对正常人和颞下颌关节功能障碍(TMJD)患者的咬肌(MM)和胸锁乳突肌(SCMM)进行了双侧表面电极的肌电检测。(1)健康受试者和TMJD受试者在有节律地移动下颌骨时，SCMM的活动与MM的活动一致。(2)在正常受试者中，咀嚼时的SCMM活性与MM活性也是一致的。而在TMJD受试者中，前者在整个过程中相当活跃。咀嚼运动，与后一种运动不协调。用α-氯醛糖麻醉猫，观察其颈下肺泡神经支配神经元(IANDN)，并分析其对外周输入的反应特性。(1)碰撞实验证实部分IANN为脊髓丘脑神经元(iAND-STN)。(2)这些神经元似乎传递牙髓或牙周组织的感觉信息。(3)在非投射的IANDN上，颈部肌肉输入汇聚。结果提示，异常的三叉神经感觉输入可能会引起异常反射，从而引起颈肌兴奋。

Neck and/or Jaw muscle pain is sometimes observed in patients suffering from pulpal and/or periodontal diseases. It is reasonable to consider that these symptoms were caused by the extraordinary excitability of the muscles. The purpose of this research project was to elucidate the muscle pain mechanisms. In a clinical study, the electromyogram of neck and jaw muscle was analyzed in human subjects, and in a basic study, the neurophysiological mechanisms underlying these symptoms were studied in animal experiments. The conclusions were as follows :1. The electromyograms of the masseter muscle(MM)and the sternocleidomastoid muscle(SCMM)were obtained with surface electrodes on both sides in healthy subjects and temporo-mandibular joint dysfunction(TMJD)patients. (1)The SCMM activity corresponded to the MM one in healthy and TMJD subjects, when they moved the mandibular without food rhythmically. (2)In healthy subjects, the SCMM activity was also corresponded to the MM one in case of mastication. While, in TMJD subjects, the former was rather active during the whole stage. of masticatory movement, and showed no harmony with the latter.2. The cervical inferior alveolar nerve-driven neurons(IANDN)were searched for in cats anesthetized with alpha-chloralose, and their response properties were analyzed in respects to the peripheral inputs. (1)Some of the IANDNS were identified as the spino-thalamic neurons(IAND-STN)using collision test. (2)These neurons seemed to relay the sensory information from the tooth pulp or the periodontal tissue. (3)Onto the non-projection IANDN, neck muscle inputs were converged. It might be occurred that neck muscle sensory inputs'integrated into the trigeminal ones in the cervical spinal cord.These results suggest that extraordinary trigeminal sensory inputs may evoke the abnormal reflex resulting in the neck muscle excitation.