Lilja J
Acta Odontol Scand. 1980;38(5):285-91. doi: 10.3109/00016358009033595.
Earlier ultrastructural investigations of human teeth have revealed differences in the innervation between crown and root dentin. In the present investigation, an intradental comparison of human teeth was made to estimate the sensitivity to different stimuli applied to two cavities, one in the buccal cusp and the other half-way between the cervix and the apex of the tooth. It was found that the pain produced by the different stimuli in the cuspal cavity was described as "sharp" or shooting, while the same stimuli applied to the root cavity provoked "dull" pain, often of a longer duration. Gentle stimuli, such as dry absorbent paper, only produced pain in the cuspal cavities. Ultrastructural examination revealed no nervous elements in the vicinity of the ground surface of the tested cavities in the crown or in the root. Odontoblastic cells including nuclei, were a common finding in the dentinal tubules of both the roots and the cusps, indicating aspiration of these cells. In some cases, in the cuspal areas, accompanying nerve-fibres had also been aspirated. The conclusion of the present investigation is that there are differences in sensibility between crown and root dentin. These differences are observed in both intensity and modality, supporting earlier findings of morphological discrepancies in the innervation of the coronal and root dentin.
早期对人类牙齿的超微结构研究揭示了牙冠和牙根牙本质在神经支配方面的差异。在本研究中，对人类牙齿进行了牙内比较，以评估对施加于两个龋洞的不同刺激的敏感性，一个龋洞位于颊尖，另一个位于牙颈部和根尖之间的中点。结果发现，在尖部龋洞中，不同刺激产生的疼痛被描述为“尖锐”或刺痛，而施加于根部龋洞的相同刺激则引发“钝痛”，且通常持续时间更长。轻柔的刺激，如干燥吸水纸，仅在尖部龋洞中产生疼痛。超微结构检查显示，在牙冠或牙根测试龋洞的表面附近未发现神经元件。包括细胞核在内的成牙本质细胞在牙根和牙尖的牙本质小管中均常见，表明这些细胞被吸出。在某些情况下，在牙尖区域，伴随的神经纤维也被吸出。本研究的结论是，牙冠和牙根牙本质在敏感性上存在差异。这些差异在强度和形式上均有观察到，支持了早期关于牙冠和牙根牙本质神经支配形态差异的研究结果。
