A PHYSIOLOGICAL STUDY ON THE CHEMICAL STIMULATION OF DENTAL PULP NERVE AND AN ETIOLOGICAL STUDY ON THE PAIN WITH PULPAL DISEASES.

本研究结合疼痛性牙髓刺激引起周围神经和中枢神经系统反应性改变的基础动物实验和口面部及头颈部疼痛与牙髓疾病关系的临床研究，对牙髓疼痛性疾病的发生机制进行了初步探讨。实验结果如下：（1）芥子油涂抹于大鼠磨牙牙髓后，可引起大鼠下颌肌静息肌电活动增加，尤其是同侧咬肌的肌电活动有明显变化。(2)芥子油刺激同侧犬牙髓，可增强猫颈髓（C2/C3）神经元对电刺激下牙槽神经（IANDN）的反应性，即在芥子油作用后，IANDN神经元兴奋性随时间延长而增强，皮肤感受野扩大。提示芥子油刺激牙髓可激活中枢致敏机制。(3)芥子油化学刺激牙髓可使牙周膜机械感受性一级纤维对压力刺激的兴奋性增加，并产生致敏作用，这种致敏作用可能通过轴突反射引起的神经源性炎症介导。(4)对因牙髓病引起的口面部及头颈部剧烈疼痛患者的临床检查表明，这些疼痛与所谓的感染根管系统密切相关，这些结果表明，用芥子油化学刺激牙髓神经提供了一种有效的方法牙髓炎性改变与疼痛关系的实验研究。

We performed a combined study of basic animal experments on the alteration of peripheral and central nervous system responsiveness with painful pulpal stimulation and clinical research on the relationship between the oro-facial, head and neck pain and the pulpal diseases. The results obtained are as follows ;(1) A small fiber exciant and inflammatory agent, mustard oil, applied to the rat molar tooth pulp, produced an increase activities in resting EMG of the rat jaw muscles, and a significant change especially in the ipsilateral masseter muscle.(2) Chemical conditionong stimulation of mustard oil to the ipsilateral canine tooth pulp enhenced the responsiveness of the cat cervical spinal cord (C2 of C3) neurons responding to the electrical stimulation to the inferior alveolar nerve (IANDN) ; that is, a temporal increase of the excitability as well as an expansion of cutaneous receptive field was observed in the IANDNs during the post-application periods of mustard oil. These results suggested that the mustard oil pulpal stimulation could activate the central sensitization mechanisms.(3) Chemical stimulation of the tooth pulp with mustard oil increased the excitability of the single periodontal mechanoreceptive primary fiber responding to the pressure stimulation to the canine tip, and produced the sensitization, which might be mediated by the neurogenic inflammation due to the axon reflex.(4) A clinical examination of the patients suffering from the severe pain in the oro-facial, head and neck region with respect to the pulpal diseases revealed that these kinds of pain were closely related with so-called infected root canal system, and that some of them were thought to be classified into the ideopathic pain groups.These results indicated that the chemical stimulation of the tooth pulp nerve with mustard oil provided useful methods in the experimental study on the relationship between the pulpal inflammatory changes and their related pain.