Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
J Endod. 2020 Sep;46(9S):S71-S80. doi: 10.1016/j.joen.2020.06.038.
The pulp-dentin complex is innervated by a high density of trigeminal neurons free nerve endings. These neuronal fibers are highly specialized to sense noxious stimuli such as thermal, mechanical, chemical, and biological cues. This robust alert system provides immediate feedback of potential or actual injury triggering reflex responses that protect the teeth from further injury. In the case of patients, pain is the most important experience that leads them to seek oral health care. The adequate removal of the etiology, such as caries, provides ample opportunity for the robust reparative and regenerative potential of the pulp-dentin complex to restore homeostasis. In addition to this elaborated surveillance system, evidence has accumulated that sensory neuronal fibers can potentially modulate various steps of the reparative and regenerative process through cellular communication processes. These include modulation of immunologic, angiogenic, and mineralization responses. Despite these orchestrated cellular events, the defense of the pulp-dentin complex may be overwhelmed, resulting in pulp necrosis and apical periodontitis. Regenerative endodontic procedures have evolved to restore the once lost function of the pulp-dentin complex. After these procedures, a large subset of successful cases demonstrates a positive response to sensitivity testing, suggesting reinnervation of the canal space. This process is likely mediated through cellular and noncellular release of neurotrophic factors such as brain-derived nerve growth factor. In addition, these newly recruited nerve fibers appear equipped to sense thermal stimuli through nonhydrodynamic mechanisms. Collectively, the significance of innervation in the normal physiology of the pulp-dentin complex and its role in regeneration need to be better appreciated to promote further research in this area that could potentially bring new therapeutic opportunities.
牙髓-牙本质复合体由高密度的三叉神经神经元无髓神经末梢支配。这些神经元纤维高度特化，能够感知有害刺激，如热、机械、化学和生物线索。这种强大的警报系统提供了潜在或实际损伤的即时反馈，触发反射反应，保护牙齿免受进一步损伤。在患者中，疼痛是导致他们寻求口腔保健的最重要的体验。充分去除病因，如龋齿，为牙髓-牙本质复合体的强大修复和再生潜力提供了充分的机会，以恢复内稳态。除了这个精细的监测系统之外，有证据表明，感觉神经元纤维可以通过细胞通讯过程潜在地调节修复和再生过程的各个步骤。这些包括对免疫、血管生成和矿化反应的调节。尽管发生了这些协调的细胞事件，但牙髓-牙本质复合体的防御可能会被压倒，导致牙髓坏死和根尖周炎。再生性牙髓治疗已发展为恢复牙髓-牙本质复合体曾经失去的功能。在这些程序之后，很大一部分成功的病例对敏感性测试表现出积极的反应，这表明管腔的再神经支配。这个过程可能是通过细胞和非细胞释放神经营养因子（如脑源性神经生长因子）来介导的。此外，这些新招募的神经纤维似乎能够通过非动力学机制感知热刺激。总的来说，神经支配在牙髓-牙本质复合体的正常生理学及其在再生中的作用需要得到更好的理解，以促进这一领域的进一步研究，这可能带来新的治疗机会。
