title: Antibacterial activity of chlorhexidine after final irrigation with ethanol: CLSM and culture-based method analysis.
abstract: This study investigated the effect of 95% ethanol on the antibacterial properties of 2% chlorexidine (CHX) over monospecies biofilm (Enterococcus faecalis) through a culture-based method, and over multispecies biofilm using confocal laser scanning microscopy (CLSM). For monospecies model, E. faecalis biofilm was induced in 40 root canals. The irrigation procedures were: S-saline solution; S/CHX-saline solution + CHX; E-ethanol; and E/CHX-ethanol + CHX. Microbial sampling was performed at three periods: before (S1), immediately after (S2), and 72 h after the final flush (S3). For multispecies biofilm model, 28 sterilized bovine dentin blocks were fixed on a removable orthodontic device to allow intraoral biofilm development. Seven samples were used in each group. Statistical analysis was carried out by using the Kruskal-Wallis test and Dunn's test for multiple comparisons. There was a significant reduction in CFUs count immediately after the final flush (S2) in all experimental groups (P < 0.05). However, only S/CHX, E and E/CHX groups had CFU counts close to zero, without differences among them (P > 0.05). After 72h (S3), the S/CHX and E/CHX groups had CFU counts near zero (P > 0.05). The CFU count increased in S3 for S and E groups (P < 0.05). CLSM showed that the percentages of remaining live cells were similar in S/CHX, E, and E/CHX groups (P > 0.05). The S group had the highest percentage of live cells (P < 0.05). The 95% ethanol did not interfere in the antibacterial properties of 2% CHX over mono- and multispecies biofilms.
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande Do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Juliana Martins
authors.initials: JM
authors.lastname: Suman
authors.affiliation: Department of Restorative Dentistry, Araraquara Dental School, São Paulo State University, Araraquara, São Paulo, Brazil.
authors.forename: Milton Carlos
authors.initials: MC
authors.lastname: Kuga
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande Do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Ricardo Abreu
authors.initials: RA
authors.lastname: Da Rosa
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande Do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Manuela Favarin
authors.initials: MF
authors.lastname: Santini
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande Do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Grazziotin-Soares
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande Do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: Montagner
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande Do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Marcus ViníCius Reis
authors.initials: MV
authors.lastname: Só
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001641:Bicuspid / Q000187:drug effects / Q000382:microbiology; D018441:Biofilms / Q000187:drug effects*; D002417:Cattle; D002710:Chlorhexidine / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D018613:Microscopy, Confocal; D012388:Root Canal Irrigants / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D012388:Root Canal Irrigants; D000431:Ethanol; D002710:Chlorhexidine
keywords: biofilms; confocal microscopy; root canal irrigants