Syringe irrigation: blending endodontics and fluid dynamics

Syringe irrigation remains a widely used irrigant delivery method during root canal treatment. An interdisciplinary approach involving well-established methods from the field of fluid dynamics can provide new insights into the mechanisms involved in cleaning and disinfection of the root canal system by this method. In addition to the equipment used clinically (syringes and needles), this chapter will also discuss the physical properties of commonly used irrigants, the flow developed inside the root canal system, irrigant refreshment, forces applied on the root canal wall, entrapment and removal of air bubbles, and the anatomical challenges faced by syringe irrigation. Essential background knowledge on fluid dynamics will also be provided

The Effect of Root Canal Irrigation with Combination of Sodium Hypo-chlorite and Chlorhexidine Gluconate on the Sealing Ability of Obturation Materials

OBJECTIVES: The aim of this study was to evaluate the effect of the precipitate that was formed by combining Sodium Hypochlorite (NaOCl) and Chlorhexidine Gluconate (CHX) on the sealing ability of root canal obturation materials. MATERIALS AND METHODS: The fluid filtration method was conducted on a total of 100 roots. Samples were randomly divided into two control (n=5) and three experimental groups (n=30). The samples in group 1 were irrigated with 1.5 mL of 2.5% NaOCl, and then the smear layers of the teeth were removed by 17% EDTA, while the specimens of group 2 were irrigated by 1.5 mL of 2.5% NaOCl and 1.5 mL of 2% CHX; after the smear layer removal, a final flush with 1.5 mL of 2.5% NaOCl was performed. The samples of group 3 were irrigated the same as group 1 but after the smear layer removal canals were irrigated again with 1.5 mL of 2.5% NaOCl and then a final flush with 1.5 mL of 2% CHX was performed. Teeth were obturated with gutta-percha and AH26 sealer and after seven days, microleakage was evaluated by the fluid filtration technique. The results were analyzed by the ANOVA and Tukey's test. RESULTS: The samples in group 3 had significantly greater microleakage compared to teeth in group 1, 2 (p<0.05), and the specimens in group 1 showed significantly less amount of microleakage than samples in group 2, 3 (p<0.05). CONCLUSION: The presence of the precipitate that is formed due to interaction between NaOCl and CHX has negative effect on the sealing ability of gutta-percha and AH26 sealer