Evaluation of chemical interactions of maleic acid with sodium hypochlorite and chlorhexidine gluconate

Introduction

The elimination of microorganisms from the root canal system necessitates the use of combination of irrigating solutions to enhance their antimicrobial property. The combination of irrigants and their interaction sometimes could be detrimental to the outcome of the root canal therapy. The purposes of this study were (1) to evaluate the interaction between 7% maleic acid (MA) and 2% chlorhexidine gluconate solution (CHX) and to find out the availability of individual irrigant and (2) to determine the free available chlorine content when 7% MA was mixed with 2.5% sodium hypochlorite (NaOCl) solution.

Methods

Interaction between MA and CHX was assessed by high-performance liquid chromatography. Available chlorine content in NaOCl was evaluated by the standard iodine/thiosulfate titration method.

Results

It was observed that more than 90% free MA and CHX were available when MA was combined with CHX. It was also observed that there was no precipitate formation when 7% MA was mixed with 2% CHX. Available chlorine content decreased significantly in the MA/NaOCl mixture.

Conclusions

There were no adverse interactions or precipitate formation observed when MA was combined with CHX, but the available chlorine content was reduced when NaOCl was mixed with MA.