Analysis of active chlorine releasing and pH of sodium hypochlorite solutions used in Endodontics

The use of a suitable irrigation solution and a correct root system shape effectively contributes to the success of endodontic treatment. Among the irrigating solutions used in Endodontics, sodium hypochlorite has been the most used because of many qualities. However, this substance must have chemical stability of its properties, by maintaining the potential of hydrogen (pH) and chlorine concentrations appropriately. Objective: The aim of this study was to evaluate active chlorine releasing and pH of some sodium hypochlorite solutions used in endodontic clinical practice. Material and methods: The solutions tested in this study were 0.5% Dakin, 1% Milton, 2% Chlorinated Soda, and household bleaches (Brilux®and Qboa®), which were opened at the same period and first used, with the same storage modus but with different manufacturing dates. The pH was measured with a digital device, and the active chlorine content was obtained through iodometric titration. Results:All solutions presented chlorine content not smaller than that informed in the flasks, ranging from 1% to 2.4%; pH was higher in all solutions, between 9 and 13. Conclusion: Based on the method applied and the results obtained, it was possible to conclude that sodium hypochlorite solutions used specifically in Dentistry (Dakin and Milton solutions and Chlorinated Soda), showed on the labels the hypochlorite content. On the other hand, household bleaches (Brilux® and Qboa®) showed the chlorine content. It was not possible to compare pH authenticity, due to lack of description on the label.