Orange-brown precipitate: A threat to the success of endodontic treatment – an in vitro study

Abstract

AIM: The aim of the present study was to evaluate the effect of various intermediate irrigating solutions in the removal of orange-brown precipitate formed due to alternative use of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) root canal irrigants. METHODS: The root canals of 50 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F3. The roots were randomly divided into five experimental groups specified by the intermediate irrigant used; Group 1: No intermediate irrigant used (control), Group 2: Saline, Group 3: 7% maleic acid (MA), Group 4: 4% sodium thiosulfate, and Group 5: 70% isopropyl alcohol (n = 10). After final irrigation with CHX, the specimens were evaluated for the presence/absence of orange-brown precipitate under stereomicroscope. RESULTS: Mean precipitate for all experimental groups was calculated using ANOVA F test which showed orangebrown precipitate (parachloroanaline) in all groups except Group 4 and Group 5 which were highly significant (p < 0.001) at all the levels of root canal. Intergroup pairwise comparison was done using Tukey’s post hoc test. CONCLUSION: About 7% MA is effective in minimizing the formation of orange-brown precipitate when used as intermediate irrigant between NaOCl and CHX. However, the precipitate was not observed with 4% sodium thiosulfate and 70% isopropyl alcohol.