Pulpal inflammation alters the physiological properties of intradental nerves in the adjacent teeth

刺激牙冠可引起牙髓血管扩张。这种血管扩张似乎是通过激活的细口径传入纤维终末释放神经肽来实现的。有人认为，当牙髓受到刺激时，牙髓中的血管扩张反应以轴突反射的形式沿着周围神经分支扩散。另一方面，电生理学和解剖学研究已经证实了支配多颗牙齿牙髓的分支神经。本研究的目的是研究刺激相邻牙齿是否会引起牙髓血流和牙内神经活动的变化，以证实支配两个牙髓的分支传入的存在。将芥子油或机械刺激应用于上颌第二前磨牙牙髓，记录同侧犬牙的牙髓血流和/或牙内神经活动。芥子油在第二前磨牙p…中的应用更多的ULP显著增加了尖牙的血流量。切断实验侧的眶下神经及其分支并不影响牙髓血流量的增加。骨膜旁注射不含血管收缩药的利多卡因可显著抑制芥子油对犬第二前磨牙牙髓血流量的增加。在某些情况下，在第二前磨牙牙髓应用芥子油的过程中和/或之后，在犬牙髓神经中记录到零星的放电或有时爆发的动作电位。部分犬记录到与机械刺激第二前磨牙髓同步放电的单髓神经单位，证实了支配双侧牙齿的分支传入神经的存在。这些结果表明，刺激第二前磨牙牙髓可能通过支配第二前磨牙和尖牙的分支传入纤维，在犬牙髓内诱发轴突反射相关的血管扩张和牙内神经放电。较少

Stimulation of the tooth crown induces vasodilation in the tooth pulp. This vasodilation seems to be mediated by the release of neuropeptides from the terminals of activated fine caliber afferent fibers. It has been suggested that the vasodilator response in the pulp spread as an axon reflex along the peripheral nerve branches when the tooth pulp is stimulated. On the other hand, branched dental nerves supplying the pulps of multiple teeth have been identified by electrophysiological and anatomical studies.The aims of this study were to investigate whether pulpal blood flow changes and intradental nerve activity can be induced by stimulation of an adjacent tooth to confirm the existence of branched afferents innervating both tooth pulps.Mustard oil or mechanical stimulation was applied to maxillary second premolar tooth pulps and pulpal blood flow and/or intradental nerve activity in the ipsilateral canine tooth were recorded in the cat. Mustard oil application to the second premolar p … More ulp significantly increased blood flow in the canine tooth. Sectioning of the infraorbital nerve and its branches on the experimental side did not affect this pulpal blood flow increase. The paraperiosteal injection of lidocaine without vasoconstrictor significantly inhibited the canine pulpal blood flow increase induced by mustard oil application to the second premolar pulp. Sporadic firing or sometimes bursts of action potentials in the canine pulp nerves were recorded during and/or after the mustard oil application to the second premolar pulp in some cases. Single pulp nerve units firing in synchrony with the mechanical stimulation of the second premolar pulp were recorded in some canines, which substantiated the existence of branched afferents innervating both teeth. These findings suggest that stimulation of the second premolar pulp may induce axon reflex-related vasodilation and intradental nerve firing in the canine pulp via branched afferent fibres innervating both the second premolar and canine teeth. Less