A vitro study of the effect of different methods of removing calcium hydroxide from root canals.

Abstract

Objective: To compare the efficiency of four methods for removing calcium hydroxide in root canals.

Methods: 80 mandibular single-tube permanent premolars were instrumented to ProTaper Universal F4. The teeth were split in two lengthwise, standardized grooves, and depressions were prepared on the wall of the root canal and filled with calcium hydroxide. The samples were randomly divided into 4 groups according to different rinsing methods, namely, syringe rinsing group (SYIG), sonic vibration group (SOIG), ultrasonic lancing Group (ULIG), and Er: YAG laser rinsing group (LAIG). The calcium hydroxide was removed from the root canal. The residual calcium hydroxide area percentage was calculated microscopically and photographed before and after rinsing. The removal effect of irregular areas (grooves and depressions) was evaluated by scoring.

Results: In the root canal crown, the clearance rate of SOIG, ULIG, and LAIG was better than that of SYIG. ULIG and LAIG had the best clearance rate (P < 0.05). In the middle root canal and root canal tip, the clearance rate of SOIG, ULIG, and LAIG was better than that of SYIG. Among them, LAIG had the best clearance rate (P < 0.05). There was no obvious difference in the clearance rate between SOIG and ULIG (P > 0.05). For the calcium hydroxide removal scores of different flushing techniques in grooves and depressions, LAIG was the best (P > 0.05).

Conclusions: None of the four methods can completely remove calcium hydroxide. However, LAIG has greater advantages than other washing methods, with higher cleaning efficiency.