Evaluation Of Removal of Calcium Hydroxide Mixed with Chlorhexidine and Detection of Precipitate

Introduction: Intracanal medication (ICM) helps to reduce the microorganisms responsible for endodontic infections and to control symptomatology. Objectives: To compare the effectiveness of different solutions - Sodium Hypochlorite 3% (NaOCl), Ethylene Diamin TetraAcetic Acid 17% (EDTA) and Citric Acid 10% (CA) - in removal of Calcium Hydroxide powder mixed with 2% Chlorhexidine gel (CH/CHX) and detection of precipitate. Materials and Methods: 45 single root teeth, 3 groups (n = 15), inserted in a silicone base, were instrumented with ProTaper Universal® files (Dentsply Sirona, Switzerland) up to F3 and divided in halves with a microtome. Two standardized grooves (coronal and apical) were filled with CH/CHX and, for their removal, NaOCl or EDTA or CA activated with E1- Irrisonic Helse Ultrasonic® tip (Helse, São Paulo, Brazil) were used. The grooves were photographed before and after application of CH/CHX. The remaining CH/CHX was evaluated using a scoring system (4 levels). Data were statistically analyzed using the Kruskal-Wallis test and the U-Mann-Whitney test with Bonferroni correction (p 0.05) and using the R system (version 3.4.2). Results: CA was higher than NaOCl and EDTA (p 0.05). There were no significant differences between the other groups (p> 0.05). Only and always, in the NaOCl group, an orange-brown precipitate was observed. Discussion: The presence of ICM may compromise the adhesion of the filling material to dentinal walls. In this sense, it's important to optimize their removal. A precipitate formation should be avoided. Conclusions: None of the solutions tested was able to completely remove the ICM; however, CA proved to be more effective than NaOCl and EDTA, and this difference was statistically significant. Clinical Implications: Removal of the ICM in test should rather be done with CA. The use of NaOCl should be avoided if the ICM contains Chlorhexidine. Keywords: calcium hydroxide, chlorhexidine digluconate, removal, EDTA, sodium hypochlorite, citric acid