Efficacy of various solutions in preventing orange-brown precipitate formed during alternate use of sodium hypochlorite and chlorhexidine: An in vitro study

AIM: The study evaluated the effectiveness of three intermediate endodontic irrigating solutions in eliminating the residual sodium hypochlorite (NaOCl), thus preventing the formation of the orange-brown precipitate when 2% chlorhexidine (CHX) is used as the final irrigant. MATERIALS AND METHODS: A total of 40 extracted human maxillary anterior teeth were selected, disinfected, and decoronated to obtain a standardized length of 10 mm. The teeth were prepared with Protaper universal rotary files until size F4 using 2.5% NaOCl as an irrigant during instrumentation. The teeth were then randomly divided into four groups of 10 samples each based on the irrigating solutions used during final wash sequence as follows: Group A - (2.5% NaOCl and 2% CHX), Group B - (2.5% NaOCl followed by 70% Isopropyl Alcohol and 2% CHX), Group C - (2.5% NaOCl followed by 6.25% sodium metabisulfite and 2% CHX), and Group D - (2.5% NaOCl followed by 3.86% sodium Thiosulfate and 2% CHX). The roots were sectioned longitudinally and the canal surface was evaluated under dental operating microscope (×16) for the presence of orange-brown precipitate. The results were tabulated as per scoring criteria and statistically analyzed. STATISTICAL ANALYSIS USED: One-way ANOVA test and post hoc Tukey's test. RESULTS: The lowest mean score was observed in Group C, followed by Group D and Group B, respectively. In comparison, there was a statistically significant (P < 0.001) difference in results between Group C and the other experimental groups. However, there was no statistically significant difference between Group B and Group D. CONCLUSION: Sodium metabisulfite was found to be very effective in preventing the formation of orange-brown precipitate.