Byers M R, Swift M L, Wheeler E F
Department of Anesthesiology, University of Washington, Seattle.
Proc Finn Dent Soc. 1992;88 Suppl 1:73-82.
The reactions of sensory nerves to restorative procedures can be classified as immediate, early and late. For each of these, the neural response depends upon the severity of pulpal injury and the stages of inflammation and healing. Immediate responses in the first few minutes include destruction of nerve fibers in the injured dentin and pulp, hypersensitivity of surviving fibers, release of neuropeptides into the pulp and neurogenic inflammation. Early responses occur during the first few days after cavity preparation, with nerve fibers sprouting in the surviving pulp and gaining increased axonal transport and neuropeptide contents. Sensory fibers containing calcitonin gene related peptide (CGRP) greatly outnumber those with substance P (SP); but both types grow toward the surviving odontoblasts and associated pulp tissue surrounding the lesion. Later during subsequent weeks the nerve fibers accompany granulation tissue as it replaces acute inflammation; and nerve sprouting subsides when inflammation is reduced and when reparative dentin covers the injury site. An important response to tooth injury that may regulate nerve sprouting reactions is the increased production of nerve growth factor (NGF) by pulpal fibroblasts near the lesion. The timing of the nerve sprouting reactions suggests that they may contribute to tooth hypersensitivity after restorative procedures.
感觉神经对修复性治疗的反应可分为即刻反应、早期反应和晚期反应。对于每一种反应，神经反应取决于牙髓损伤的严重程度以及炎症和愈合的阶段。最初几分钟的即刻反应包括损伤牙本质和牙髓中神经纤维的破坏、存活纤维的超敏反应、神经肽释放到牙髓以及神经源性炎症。早期反应发生在窝洞制备后的最初几天，存活牙髓中的神经纤维发芽，轴突运输和神经肽含量增加。含有降钙素基因相关肽（CGRP）的感觉纤维数量远多于含有P物质（SP）的纤维；但这两种类型的纤维都向存活的成牙本质细胞和病变周围的相关牙髓组织生长。在随后的几周内，随着肉芽组织取代急性炎症，神经纤维也随之生长；当炎症减轻且修复性牙本质覆盖损伤部位时，神经发芽消退。对牙齿损伤的一种重要反应，可能调节神经发芽反应的是病变附近牙髓成纤维细胞神经生长因子（NGF）产量的增加。神经发芽反应的时间表明，它们可能导致修复性治疗后牙齿过敏。
