Calcium hydroxide as a temporary filling of the post space in root-filled teeth

Objective. The purpose of this in vitro study was to evaluate whether the saline content of the calcium hydroxide paste used as a temporary filling in the post space of root-filled teeth would significantly affect the seal of the apical root fillings (gutta-percha and zinc oxide-eugenol based sealer) during a period of 1 month. Study design. Eighty extracted single-rooted and multirooted teeth were cut at the cemento-enamel junction. They were endodontically instrumented and filled with zinc oxide-eugenol based sealer and gutta-percha. A post space was immediately prepared on 70 teeth. The experimental teeth were then randomly divided into 4 groups: A, post space filled with calcium hydroxide paste (30 teeth); B, post space without calcium hydroxide paste (30 teeth); C, negative controls (10 teeth); and D, positive controls (10 teeth). The teeth were stored in a humidified chamber at room temperature for a month. After storage, the calcium hydroxide paste in the post spaces in group A was removed. All roots were coated with 2 layers of nail varnish and sticky wax externally, placed in a glass bottle containing methylene blue, and subjected to a vacuum for 15 minutes. The teeth were then stored for another week, sectioned in half longitudinally, and examined for dye penetration. The mean and standard deviation of dye penetrations for each group were calculated, and a Student t test was used to determine the statistical difference between the groups. Results. There was no significant difference in the coronal dye leakage of the apical root fillings between the post spaces filled with the calcium hydroxide paste and those without during a period of 1 month. Conclusions. The saline content in the calcium hydroxide paste placed in the post space as a temporary filling did not significantly affect the seal of the apical root fillings during a period of 1 month by using a dye leakage study.