Interaction of blood flow and nerve function in the dental pulpitis

牙髓中有丰富的神经和血管。这些神经和血管彼此密切相关。特别是在感觉神经轴突密集支配的牙髓中，由于p物质等血管舒张神经肽的释放，容易发生由感觉神经介导的反顺性血管舒张。这种血管舒张反应增加了牙髓内压力和紊乱的静脉血液流出。结果，牙髓陷入循环紊乱。牙髓中还存在由α -肾上腺素受体介导的交感血管收缩系统，而不存在由β -肾上腺素受体介导的血管舒张系统。牙髓中明显缺乏副交感神经血管扩张系统，尽管口腔-面部区域的许多其他组织都有这些系统。牙髓缺乏副交感神经血管扩张可能被认为是牙髓血流调节的一个特征；由于牙髓具有封闭和低顺应性的系统，它可能有利于避免循环障碍。(2)我们设计了一种通过监测牙髓血流来评估人类牙髓活力的新方法。牙髓血流量是通过激光传输来测量的，激光从牙齿的颊面传输，从腭面接收。这个仪器不是评估牙髓的敏感性，而是评估牙髓本身的活力。此外，它不会给病人带来痛苦，因此是客观的。这一新系统有望用于口腔疾病的诊断。

(1) The dental pulp is rich in both nerves and blood vessels. These nerves and vessels are closely related to each other. Particularly in the dental pulp, which is densely innervated by sensory nerve axons, antidromic vasodilatation mediated via sensory nerves easily occurs as a result of the release of vasodilator neuropeptides such as substance P.Such vasodilator responses increase intra-pulpal pressure and disturbvenous blood outflow. Consequently, the dental pulp falls into circulatory disturbance.A sympathetic vasoconstriction system mediated via alpha-adrenoceptors also exists in the dental pulp, whereas a vasodilator system mediated via beta-adrenoceptors is absent.Parasympathetic vasodilator systems are apparently lacking in the dental pulp, although many other tissues in the oro-facial region have these systems. The lack of parasympathetic vasodilatation in the dental pulp may be considered a characteristic feature of the regulation of pulpal blood flow ; it may be beneficial for the dental pulp, with its enclosed and low-compliance system, to avoid circulatory disturbances. (2) We designed a new method for the assessment of human tooth pulp vitality by monitoringpulpal blood flow. Pulpal blood flow is measured by means of a transmitted laser light, which is transmitted from the buccal surface of the tooth and received from the palatalsurface. This apparatus does not assess sensitivity of the dental pulp, but pulp vitality itself. Further, it causes no pain to the patient and is therefore objective. This new system is expected to be useful in the diagnosis of oral diseases.