[The effect of calcium hydroxide eugenol agents on pulp of primary teeth of young dogs. The view of early stages].

Eugenol has such effective anti-corrosion and pain-killing properties that it is widely used for dentistry clinically. We focused our attention on eugenol and made agents for pulpotomy which were mixtures of calcium hydroxide, eugenol and polyethylene glycol 4000 for a base. We attempted to use them for the pulpotomy of primary teeth of young dogs and observed the healing progress of the treated teeth during the early stages. The experiment utilized four young dogs whose primary teeth were pulpotomized by the usual method. Agents of the pulpotomy were mixed calcium hydroxide (1.0 g), eugenol (0.8 ml) and polyethylene glycol 4000 (1.2 ml). After 3 days and 7 days, these teeth were taken out to be made into histopathological specimens. We inspected them microscopically. The results obtained were as follows. 1) After 3 days, the amputated pulp which was in contact with the agents turned into necrotic layers. Degenerative, necrotic, and non-structural states were widely observed. Under the necrotic layers, there were hematoxyline dark stained layers. Also the hematoxyline dark stained layers separated from the proper pulp. In the proper pulp, there were no abnormalities. 2) After 7 days, the necrotic layers were atrophied. In the dark stained layers, the stained areas were darker than that of after 3 days and increased in degeneration. In the proper pulp, round cells appeared and with a chronic inflammatory appearance along with vacuole, atrophy and degeneration. It seemed to be affected by eugenol. Dentin bridges still has not yet formed.