CASE REPORT Outcome of endodontic treatment with chlorhexidine gluconate as main irrigant: A case series Hair Salas, DDS, MSc, PhD 1 ; Gaya C.S. Vieira, DDS, MSc, PhD 2 ; Ivo Palomino, DDS, MSc 1 ; Javier Valero, DDS, MSc 1 ; Juan Pacheco-Yanes, DDS, MSc 3 ; Andrea F. Campello, DDS, MSc, PhD 2 ; and Alejandro R. P erez, DDS, MSc, PhD 2 1 School of Dentistry of the Catholic University of Santa Maria, Arequipa, Per u 2 Department of Endodontics and Dental Research, Iguac ßu University (UNIG), Nova Iguac ßu, Brazil 3 Post-graduation Program in Dentistry, Est acio de S a University, Rio de Janeiro, Brazil Keywords apical periodontitis, chlorhexidine gluconate, outcome, post-treatment apical periodontitis, vital teeth. Correspondence Hair Salas, Urb. Santo Domingo L-2 II etapa JLB y Rivero, Arequipa, Per u. Email: hairsalas71@hotmail.com doi: 10.1111/aej.12401 (Accepted for publication 16 February 2020.) Abstract This study evaluated the overall endodontic therapy success using 0.12% or 2% chlorhexidine gluconate as main irrigant. Seventy-two teeth diagnosed as vital, necrotic or previously treated teeth with apical periodontitis that were consecutively treated by orthograde therapy. All cases were followed clinically and radiographically for at least 1-year period. Success was established in teeth without signs or adverse clinical symptoms and complete or incomplete radio- graphic healing. Failure was determined in teeth with any sign or adverse clin- ical symptoms and a new, unchanged or enlarged radiographic periapical lesion. The data were analysed using chi-square and Fischer’s exact tests. The overall success rate for teeth undergoing vital pulp was 84.6%, 76.2% as for the necrotic teeth and 84% for the retreatment cases. No significant differences were observed between groups (P > 0.05). Cases treated with CHX as main irrigant showed a high overall endodontic therapy success rate. Introduction Apical periodontitis is an infectious disease caused by the colonisation of microorganisms in the root canal system ((1,2)). The success of endodontic therapy depends on the effective control of infection, and in this regard, chemomechanical preparation plays a pivotal role in the reduction of bacterial load to levels compatible with the tissues repair ((3)). Mechanical preparation associated with an inert solution has shown to significantly decrease the number of bacterial cells in the root canal ((4,5)); however, in most cases, microorganisms persist after preparation ((4,6)), evidencing the importance of using an irrigant with antimicrobial action. Sodium hypochlorite (NaOCl) is the most frequently used root canal irrigant in endodontics ((7)) because it has a great tissue-dissolving ability ((8)) and excellent antimicrobial activity ((9)). However, NaOCl has an irri- tating potential of periapical tissues, especially at high concentrations ((10,11)). Thus, chlorhexidine gluconate (CHX) has been proposed as a substitute for NaOCl. CHX cannot dissolve pulp tissue ((12)) but has an excellent antimicrobial ability ((13)) and substantivity that main- tain an antibacterial effect for extended periods of time ((14)). Since microbial reduction has shown to be a strong predictor of the outcome ((15,16)), several clinical stud- ies have compared the antimicrobial effectiveness of NaOCl and CHX showing inconsistent results ((13,17– 19)). A recent systematic review concluded that informa- tion on this topic is scarce and clinical studies comparing overall success with both solutions are necessary ((20)). Ng, Mann ((21)) showed a significantly lower success rate when CHX was used as an additional step to optimise disinfection in cases with persistent exudate, inflamma- tion, pain or sinuous tract. Another recent study com- pared the success of endodontic therapy in teeth with post-treatment apical periodontitis using as the main irri- gant the CHX or NaOCl and no significant differences were observed between the groups ((22)). To the best of our understanding, there are no studies evaluating the final treatment outcome in teeth with absence and presence of apical periodontitis using CHX as the main irrigant. Therefore, this case series study © 2020 Australian Society of Endodontology Inc 1 Aust Endod J 2020