T ABSTRACT www.fob.usp.br/jaos or www.scielo.br/jaos EFFICACY OF SODIUM HYPOCHLORITE AND CHLORHEXIDINE AGAINST Enterococcus faecalis ��� A SYSTEMATIC REVIEW Carlos ESTRELA1, Julio Almeida SILVA2, Ana Helena Gon��alves de ALENCAR3, Claudio Rodrigues LELES4, Daniel Almeida DECURCIO2 1- DDS, MSc, PhD, Chairman and Professor of Endodontics, Federal University of Goi��s, Goi��nia, GO, Brazil. 2- DDS, MSc, Professor of Endodontics, Federal University of Goi��s, Goi��nia, GO, Brazil. 3- DDS, MSc, PhD, Professor of Endodontics, Federal University of Goi��s, Goi��nia, GO, Brazil. 4- DDS, MSc, PhD, Professor of Prevention and Oral Rehabilitation, Federal University of Goi��s, Goi��nia, GO, Brazil. Correspondence address: Prof. Carlos Estrela - Centro de Ensino e Pesquisa Odontol��gica do Brazil (CEPOBRAS) - Rua C-245, Quadra 546, Lote 9, Jardim Am��rica - 74.290-200, Goi��nia, GO, Brazil - e-mail: estrela3@terra.com.br Received: December 05, 2007 - Modification: June 16, 2008 - Accepted: June 17, 2008 he efficacy of the sodium hypochlorite (NaOCl) and chlorhexidine (CHX) on Enterococcus faecalis was evaluated by systematic review and meta-analysis. The search strategies included search in electronic biomedical journal databases (MEDLINE, EMBASE, CENTRAL) and handsearching records, using different matches of keywords for NaOCl, CHX and Enterococcus faecalis. From 41 in vivo studies, 5 studies met the inclusion criteria. In a sample containing 159 teeth, E. faecalis was detected initially in 16 (10%) teeth by polymerase chain reaction (PCR) and 42 (26.4%) teeth by microbial culture techniques. After root canal disinfection, this species was observed in 11 (6.9%) teeth by PCR and 12 (7.5%) teeth by culture. Risk differences of included studies were combined as generic inverse variance data type (Review Manager Version 5.0 ��� Cochrane Collaboration, http://www.cc-ims.net, accessed 15 May 2008), taking into account the separate tracking of positive and negative cultures/PCR. The level of statistical significance was set at p0.05. In conclusion, NaOCl or CHX showed low ability to eliminate E. faecalis when evaluated by either PCR or culture techniques. Key words: E. faecalis. Sodium hypochlorite. Chlorhexidine. Irrigating solutions. Systematic review. INTRODUCTION The pathogenicity of endodontic microorganisms responsible for stimulating apical periodontitis creates the need for finding effective antimicrobial medicaments16. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) are the most frequently widely studied and employed antimicrobial agents for treatment of root canal infection2,5. These medicaments present chemical characteristics that are particularly responsible for their distinct results when compared1,6,20,23. These variations occur probably due to differences in methodology, biological indicators, concentrations, exposure time, the potential for different anatomical and treatment differences between patients1,6,20,23,27. The contemporary literature contains numerous reports on the antimicrobial efficacy of NaOCl and CHX in several experimental models - infected human teeth in vivo7,16-18,29,30, infected human teeth ex vivo4, infected dog���s teeth in vivo5,21, infected bovine teeth ex vivo10, biofilm model in membrane filters22,25, direct contact and agar diffusion test6,9. E. faecalis is an extensively evaluated biological indicator12,15,19,26,27. Some factors can explain the concern with this pathogen in endodontic infections. Its high prevalence in cases with post-treatment disease associated with virulence factors (aggregation substance, enterococcal surface proteins (Esp), gelatinase, cytolysin toxin, extracellular superoxide production, capsular polysaccharides, antibiotic resistance determinant) can facilitate the adherence of host cells and extracellular matrix, tissue invasions, immunomodulation effect and cause toxin- mediated damage19. Actual thinking has recommended the implementation of evidence-based dentistry, which valorizes studies involving the systematic review or meta-analysis. Systematic reviews use a strict methodological approach to search, select, evaluate, and analyze original data from primary sources. Good scientific evidence is mandatory to elaborate clinical decisions, yet few systematic reviews or meta- analysis have been developed in Endodontics14,21,28. 364 J Appl Oral Sci. 2008 16(6):364-8

Torabinejad and Babjri28 reported that the American Dental Association has adopted the concept of evidence-based healthcare, which requires the judicious integration of systematic assessments of clinically relevant scientific evidence. Previous studies using in vitro experimental models have confirmed the antimicrobial efficacy of NaOCl and CHX against E. faecali6,23, while others using different study designs have not found same results4,5,7,16-18,29,30. Relevant clinical questions based on evidence regarding the resistance of E. faecalis to NaOCl or CHX should be further discussed. Therefore, the aim of this study was to review findings on the antibacterial efficacy of NaOCl or CHX against E. faecalis in endodontic infection using systematic review and meta-analysis. MATERIALS AND METHODS Literature Review This study was designed using an analysis of longitudinal studies from a quantitative systematic review. Prospective studies were selected towards the efficacy of NaOCl and CHX against E. faecalis identified in endodontic infections before and after root canal preparation. English-language articles were retrieved from electronic biomedical journal databases and handsearching records. The following databases were searched on January 2nd, 2007: MEDLINE (without filter, from 1966 to January 2nd, 2007), EMBASE (without filter, from 1980 to January 2nd, 2007), Cochrane Oral Health Group Trials Register and Cochrane Central Register of Controlled Trials (CENTRAL). For the electronic search strategy, the following terms were used as keywords in several combinations: 1. faecalis and sodium hypochlorite OR, 2. faecalis and chlorhexidine OR, 3. faecalis and root canal infections OR, 4. faecalis and endodontics infections OR, 5. faecalis and root canal irrigants OR, 6. faecalis and irrigating solution OR, 7. faecalis and endodontics irrigants OR, 8. faecalis and intracanal irrigants. A systematic review was conducted according to the guidelines of the Cochrane Collaboration, which recommend the search for the largest possible number of articles. Handsearching was conducted by the review of the reference lists of the eligible clinical trials and the review of author���s personal databases of trial reports in an attempt to identify any other relevant studies. Inclusion and Exclusion Criteria The selected articles were identified from titles and abstracts by two independent reviewers, considering the tabulated inclusion and exclusion criteria.. The inclusion criteria were studies in humans, studies related to the efficacy of NaOCl or CHX against E. faecalis, nonsurgical root canal treatment performed during the study, subjects with a noncontributory medical history, microbiological samples collected before and after root canal preparation, English- language articles. The exclusion criteria were in vitro and animal studies, studies related to the efficacy of intracanal irrigants and medications other than NaOCl or CHX, studies without collection of microbiological samples before or immediately after root canal preparation, non-English- language articles, studies abstract only or no abstract, literature reviews, studies involving primary teeth, case reports, studies related only to microbial identification or studies involving microorganisms other than E.faecalis. Full-text reprints were obtained from all relevant and potentially relevant studies, which seemed to meet the inclusion criteria and from those that had insufficient data in the title and abstract to make a clear decision. Meta-Analysis The design of this meta-analysis was based on the guidelines of the Cochrane Collaboration and on the methodology of previous study21. Chi-square test was used to analyze the differences between the studies. The essential analysis of antibacterial efficacy was risk difference (difference in the ratio of positive bacterial identification TABLE 1- Studies included related to the efficacy of the NaOCl and CHX against E. faecalis (n - number of samples, IET- initial endodontic treatment, RCP ��� root canal preparation) 365 EFFICACY OF SODIUM HYPOCHLORITE AND CHLORHEXIDINE AGAINST Enterococcus faecalis ��� A SYSTEMATIC REVIEW