A text-book of dental histology and embryology, including laboratory directions . l tubules. Fig. 162 g «5f£ Nerve fibers in pulp from a human molar. (About 500 X) The sensitiveness of the dentine, in view of these obser-vations, is due to the presence of living fibrils, connectedwith living odontoblasts which are in physiologic connec-tion with nerve fibers. It is interesting to note that this isthe only instance in which a connective-tissue cell is inter-mediate between the outside world and the nerve fiber. In 216 DENTAL PULP all other instances an epithelial cell is intermediate betweenthe
A text-book of dental histology and embryology, including laboratory directions . l tubules. Fig. 162 g «5f£ Nerve fibers in pulp from a human molar. (About 500 X) The sensitiveness of the dentine, in view of these obser-vations, is due to the presence of living fibrils, connectedwith living odontoblasts which are in physiologic connec-tion with nerve fibers. It is interesting to note that this isthe only instance in which a connective-tissue cell is inter-mediate between the outside world and the nerve fiber. In 216 DENTAL PULP all other instances an epithelial cell is intermediate betweenthe environment and the nervous system. The sensitivenessof the dentine is therefore due to the irritability of the cyto-plasm of the fibril, transmitted through the continuity ofcytoplasm to the odontoblasts and their reaction upon thesurrounding nerve fibers. The irritation to the fibril maybe either traumatic, chemical, or thermal. For instance, saltis sprinkled on exposed living dentine, and a sharp sensa-tion of pain is the result. It may be supposed that chemical Fig. 163. Roses diagram of nerves and bloodvessels of the pulp. changes are set up in the cytoplasm of the fibril which excitechanges in the cytoplasm of the odontoblasts. These reactupon the cytoplasm of the nerve fiber, and so are transmittedto the nerve centre, being recognized, in consciousness, as asensation of pain. In the same way traumatic irritationcaused, for instance, by the cutting of dentine with a steelinstrument sets up changes in the fibril in the same is impossible to conceive of any vital activity of cyto-plasm otherwise than as a form of chemical action or molec-ular or atomic movement of its substance. THE NERVES OF THE DENTAL PULP 217 Certain clinical facts are well explained by these structuralfacts. It is often noted in the preparation of cavities thatthe dentine is most sensitive at the dento-enamel would be expected when it is recalled that at the dento-enamel junc
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectteeth, bookyear1912
