International Endodontic Journal, 33, 494 – 504, 2000 © 2000 Blackwell Science Ltd 494 Blackwell Science, Ltd Cleaning effectiveness of root canal irrigation with electrochemically activated anolyte and catholyte solutions: a pilot study A. M. Solovyeva 1 & P. M. H. Dummer 2 1 Faculty of Stomatology, St. Petersburg I.P. Pavlov’s State Medical University, St. Petersburg, Russia CIS; and 2 Department of Adult Dental Health, University of Wales College of Medicine, Cardiff, UK Abstract Solovyeva AM, Dummer PMH. Cleaning effectiveness of root canal irrigation with electrochemically activated anolyte and catholyte solutions: a pilot study. International Endodontic Journal, 33, 494 – 504, 2000. Aim The aim of this study was to evaluate the potential of electrochemically activated (ECA) anolyte and catholyte solutions to clean root canals during conventional root canal preparation. Methodology Twenty extracted single-rooted human mature permanent teeth were allocated randomly into four groups of five teeth. The pulp chambers were accessed and the canals prepared by hand with conventional stainless steel endodontic instruments using a double- flared technique. One or other of the following irrigants was used during preparation: distilled water, 3% NaOCl, anolyte neutral cathodic (ANC) (300 mg L –1 of active chlorine), and a combination of anolyte neutral cathodic (ANC) (300 mg L –1 of active chlorine) and catholyte. The teeth were split longitudinally and the canal walls examined for debris and smear layer by scanning electron microscopy. SEM photomicrographs were taken separately in the coronal, middle and apical parts of canal at magni- fication of ×800 to evaluate the debridement of extra- cellular matrix and at a magnification of ×2500 to evaluate the presence of smear layer. Results Irrigation with distilled water did not remove debris in the apical part of canals and left a continu- ous and firm smear layer overlying compressed low- mineralized predentine. All chemically active irrigants demonstrated improved cleaning potential compared to distilled water. The quality of loose debris elimina- tion was similar for NaOCl and the anolyte ANC solution. The combination of anolyte ANC and catholyte resulted in improved cleaning, particularly in the apical third of canals. The evaluation of smear layer demonstrated that none of the irrigants were effect- ive in its total removal; however, chemically active irrigants affected its surface and thickness. Compared to NaOCl, the ECA solutions left a thinner smear layer with a smoother and more even surface. NaOCl enhanced the opening of tubules predominantly in the coronal and middle thirds of canals, whereas combination of ANC and catholyte resulted in more numerous open dentine tubules throughout the whole length of canals. Conclusions Irrigation with electrochemically activated solutions cleaned root canal walls and may be an alternative to NaOCl in conventional root canal treatment. Further investigation of ECA solutions for root canal irrigation is warranted. Keywords: cleaning, debridement, electrochemically activated solutions, root canal. Received 22 November 1999; accepted 6 January 2000 Introduction Elimination of microorganisms from the root canal system is one of the objectives of root canal treatment (Byström et al. 1987) and has a substantial effect on the outcome (Lin et al. 1992, Sundqvist et al. 1998). Unfortunately, microorganisms may remain after conven- tional canal preparation, either within the dentine tubules (Peters et al. 1995), embedded in the smear layer (Huque et al. 1998) or bound within the apical dentine plug (Nair et al. 1990, Abou-Rass & Bogen 1998). It is generally believed that mechanical enlargement Correspondence: Professor Paul Dummer, Department of Adult Dental Health, Dental School, University of Wales College of Medicine, Heath Park, Cardiff CF14 4JX, UK (fax: +44 (0)29 20742479; e-mail: dummer@cardiff.ac.uk).