Abstract
The purpose of this study was to find the shortest application period of Ca(OH)2 for dentin bridge formation after vital pulpotomy. It also aimed at evaluating the pulpal changes and dentin bridge formation after removal of Ca(OH)2 and necrotic tissue following vital pulpotomy. Rat molars were used and the period of application of Ca(OH)2 was for a one, seven, fourteen, or forty two days. The experiment lasted 42 days. Histopathological changes of the pulp and dentin bridge formation were observed. Statistical analysis was done using Fisher's exact probability method.
The results were as follows after the 42 day period of the experiment.
1) A dentin bridge was formed in teeth for which the duration of application period of Ca(OH)2 was one or seven days. The probability of dentin bridge formation was lower however, in teeth for which the duration of the application period was fourteen days. The dentin bridge formation was evident in teeth with fourteen days of application of Ca(OH)2.
2) Necrotic tissue was observed again at forty two days, even if the Ca(OH)2 and necrotic tissue were removed at one, seven or fourteen days during which the dentin bridge formation was not yet observable.
These findings suggest that the dentin bridge formation is best shown with a 14-day application period of Ca(OH)2, but removal of Ca(OH)2 and necrotic tissues at this time shows reformation of necrotic tissue. It is therefore suggested that clinical removal of Ca(OH)2 and necrotic tissues be done later when the dentin bridge formation is completed.
