Electron microscopic study on nerve terminals during dentin bridge formation after pulpotomy in dog teeth.

This study was designed to examine the relation between pulpal nerves and the differentiation of pulpal cells into preodontoblasts and odontoblasts during the healing process after pulpotomy. A total of 36 upper and lower teeth obtained from six adult dogs were used. The pulp chamber was opened with a sterile diamond bur, the coronal pulp was exposed, and the whole surface of the amputated pulp was capped with calcium hydroxide. The interval between pulpotomy and extraction was 5, 7, 10, 15, 20, 30, 40, 50, and 60 days, and then specimens were examined ultrastructurally. Close contact between fibroblast-like cells/osteoblast-like cells and nerve terminals at the calcification front was observed in the early healing process after pulpotomy, suggesting a close relation between nerve fibers and pulpal cell differentiation.