Research Article The Effect of Essential Oils and Bioactive Fractions on Streptococcus mutans and Candida albicans Biofilms: A Confocal Analysis Irlan Almeida Freires, 1 Bruno Bueno-Silva, 2 Lívia Câmara de Carvalho Galvão, 1 Marta Cristina Teixeira Duarte, 3 Adilson Sartoratto, 3 Glyn Mara Figueira, 3 Severino Matias de Alencar, 4 and Pedro Luiz Rosalen 1 1 Pharmacology, Anesthesiology and herapeutics, Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, 13414-903 Piracicaba, SP, Brazil 2 Department of Microbiology, Institute of Biomedical Sciences, University of S˜ ao Paulo, 05508-900 S˜ ao Paulo, SP, Brazil 3 Research Center for Chemistry, Biology and Agriculture, University of Campinas, 13083-970 Campinas, SP, Brazil 4 Department of Agri-Food Industry, Food and Nutrition, “Luiz de Queiroz” College of Agriculture, University of S˜ ao Paulo, 13418-900 Piracicaba, SP, Brazil Correspondence should be addressed to Pedro Luiz Rosalen; rosalen@fop.unicamp.br Received 28 December 2014; Revised 6 February 2015; Accepted 9 February 2015 Academic Editor: Gloria Brusotti Copyright © 2015 Irlan Almeida Freires et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. he essential oils (EO) and bioactive fractions (BF) from Aloysia gratissima, Baccharis dracunculifolia, Coriandrum sativum, Cyperus articulatus, and Lippia sidoides were proven to have strong antimicrobial activity on planktonic microorganisms; however, little is known about their efects on the morphology or viability of oral bioilms. Previously, we determined the EO/fractions with the best antimicrobial activity against Streptococcus mutans and Candida spp. In this report, we used a confocal analysis to investigate the efect of these EO and BF on the morphology of S. mutans bioilms (thickness, biovolume, and architecture) and on the metabolic viability of C. albicans bioilms. he analysis of intact treated S. mutans bioilms showed no statistical diference for thickness in all groups compared to the control. However, a signiicant reduction in the biovolume of extracellular polysaccharides and bacteria was observed for A. gratissima and L. sidoides groups, indicating that these BF disrupt bioilm integrity and may have created porosity in the bioilm. his phenomenon could potentially result in a weakened structure and afect bioilm dynamics. Finally, C. sativum EO drastically afected C. albicans viability when compared to the control. hese results highlight the promising antimicrobial activity of these plant species and support future translational research on the treatment of dental caries and oral candidiasis. 1. Introduction It has been long known that bioilms formed by Streptococcus mutans and Candida albicans are implicated in the establish- ment of dental caries and oral candidiasis, respectively, and constitute complex structures, oten composed of interactive microorganisms which are organized for increased metabolic eiciency, resistance to stress, and virulence [1] with a sophis- ticated quorum sensing system [2]. Extracellular polysaccharides (EPS) produced by S. mutans glycosyltransferases are the main constituents in the matrix of cariogenic bioilms and are recognized as critical virulence factors associated with dental caries [3]. An EPS- rich matrix creates highly adhesive, interconnected, and acidic environments, which ultimately leads to the clinical onset of cavitation through acid demineralization of the adjacent enamel [4]. he EPS matrix provides a three- dimensional scafold for bioilm development and assembly, which confers increased resistance to antimicrobials and cre- ates signaling pathways [3]. Bioilm formation on host tissues or medical devices mediated either by biotic (cell-surface proteins) or abiotic (surface hydrophobicity) factors also plays a role in the patho- genesis of yeast infections [5]. Hindawi Publishing Corporation Evidence-Based Complementary and Alternative Medicine Volume 2015, Article ID 871316, 9 pages http://dx.doi.org/10.1155/2015/871316