抄録
1. Electron microscope studies concerning the histologic nature of the dentinal canal, wall of the dentinal canal and odontoblast process are reported.
2. The dentinal canal is found immediately around the odontoblast process, that is, it exists between the odontoblast process and peri-process area, but no appreciable space is detected between them. Therefore, the diameter of the odontoblast process corresponds to that of the dentinal canal.
3. The peri-process area (corresponding to the ring-shaped area around the odontoblast process) is the thick, more highly mineralized wall of the dentinal canal than the rest of the dentin, encircling in its center the odontoblast process. The external diameter of the peri-process solid area is corresponding to the classically accepted dentinal canal. The peri-process solid area is distributed by innumerable fine fibrils of no cross-striations which extend toward the interior of the intertubular dentin matrix. From this point of view, the peri-process solid area is histologically different from the dentin matrix (so-called intertubular matrix) where there are found cross-striations peculiar to collagen fibrils.
4. The odontoblast process covered with some organic layer is intimately engirdled by the thick highly calcified wall of the dentinal canal.
