Comparative evaluation of intermediate solutions in prevention of brown precipitate formed from sodium hypochlorite and chlorhexidine gluconate

Abstract

Objectives: To evaluate intermediate treatments between sodium hypochlorite and chlorhexidine gluconate irrigations for the prevention of a toxic brown precipitate in root canal therapy. Materials and Methods: Thirty-nine premolars were irrigated with 6% sodium hypochlorite and divided into either: No intermediate treatment; Dry paper points; three different irrigations with 17% ethylenediaminetetraacetic acid, deionized water, or 5% sodium thiosulfate. 2% chlorhexidine gluconate was the final irrigant in all groups. Sectioned teeth were analyzed for brown precipitate intensity and area using stereomicroscopy and components related to para-chloroaniline using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Results: Stereomicroscopy showed that 5% STS significantly reduced brown precipitate intensity and area as compared with no intermediate irrigation (p