抜歯創の治癒にともなう神経分布の消長に関する実験的研究

抄録

A total of 140 teeth was extracted from 37 dogs and pathonervehistological studies were conducted on the extraction wounds from the 1st day to the 70th day of extraction, and behavour (change) of the nerve tissues in the socket and its periphery during the healing process was studied in detail. Results are summarized as follows : 1. The healing process as studied in the present extraction wounds seemed to follow the usual pattern of wound healing. 2. Immediatly after extraction, nerve fibers in the extraction wounds and peripheral tissues suffered the so-called Wallers degeneration, which was most severe until 3rd day of operation, but the degeneration was not seen by the 7th day. 3. The regeneration of the nerve fiber started by the 3rd day, and became most vigorous by the 7th day. By the 5th day, large nerve plexus consisting of fine nerve fibers came to be formed around the bundles of the degenerated nerve fibers in the space between blood vessels at the bottom of socket. 4. By the 6th day after extraction, there were seen in the granulation tissue two distinct groups of nerve fiber bundles, one of which ascended along the wall and the other through the middle of the wound socket. 5. After the 10th day of extraction, both groups of the nerve fibers reached as high as the top of the socket, and several small bundles of nerve fibers and relatively large-sized single fibers were seen branching off in the midway to distribute in the granulation tissues and newly formed bony structure. 6. After the 30th day of extraction, large networks of blood vessel accompanying nerve fibers were seen to destribute in Haversian canals in the new bone as well as in the bone marrow, and by the 40th day the whole picture became indistinguishable from that of nerve distribution in the surrounding alveolar bone. 7. The whole process of nerve distribution in the healing of tooth extraction wound could be distinguished into the following 4 stages. 1. 1st day to 3rd day after extraction : degeneration stage 2. 3rd to 3rd week : regeneration stage 3. 3rd week to 1st month : readjustment stage 4. After 30th day : completion 8. The extremely fine nerve fibers that were observed in great abundance may be of vegetative origin, and these became sparse and finally disappeared with progress and completion of ossification in the tooth socket. 9. The nerve fibers of fairly large size which made appearance at around 7th day of the beginning of granulation when the granulation in the extraction socket was complete proved to be of sensory origin.