ABSTRACT
Objective: To study the effect of different wetness degrees in the root canal on the canal sealing. Methods: 160 root canal prepared single rooted teeth were divided into 4 groups (n = 40) by the root canal wetness degree (water content, V): (1) 0. 250 ～0. 299, (2) 0. 300 ～ 0. 599, (3) 0. 600 ～ 0. 899 and (4) 0. 900 ～ 1. 199 respectively. 80 teeth were divided into 4 groups (n = 20) for dye leakage test and another 80 for bacterial microleakage test. Zinc oxide paste (ZOP) and AH-Plus (AH-P) with vertical condensation of warm gutta-percha were respectively used to seal the canals in each group of the samples (n = 10) . The length of in vitro tooth dye penetration was measured by stereomicroscope; the time (days) of turbidity in the bacterial leakage model observed and compared. Results: Of all the canals sealed by ZOP or AH-P with the increase of the wetness the dye infiltration length increased significantly (P ＜0. 05) and the days in which the faecal intestine ball infiltrated into the lower chamber of the model was gradually decreased (P ＜0. 05) . Conclusion: The increase of root canal moisture may reduce the sealing of the root canal.