Antimicrobial activity of experimental chitosan solutions on acrylic resin and cobalt-chromium surfaces

Purpose: To evaluate the applica.on of chitosan as a cleanser in the control of biofilm forma.on on cobalt-chromium (Co-Cr) alloy and acrylic resin surfaces. Materials and Methods: In total, 172 Co-Cr discs and 172 acrylic resin discs (14 mm x 3 mm) were contaminated with Streptococcus mutans, Staphylococcus aureus, Candida albicans, or Candida glabrata and incubated for 48 hours. Then, specimens were randomly divided into groups and immersed in the following solu.ons for 15 minutes: solu.on without chitosan (WC/control); chitosan solu.on (CH: 5 mg/mL); chitosan nanopar.cle solu.on (CN: 3.8 mg/mL); and effervescent tablet (ET). Biofilm recovery rates (n = 9) were evaluated by coun.ng the colony-forming units (CFU/mL). Biofilm morphology was evaluated using scanning electron microscopy (SEM). Data were compared using the Kruskal-Wallis or ANOVA tests followed by the Tukey post hoc test. Results: For acrylic resin, ET showed the lowest number of CFU for S aureus and S mutans (P < .001). CH exhibited intermediate values for S mutans, S aureus, and C albicans; CN exhibited intermediate values for S mutans and S aureus. For C glabrata, there was no statistical difference between the solutions (P = .264). For Co-Cr, ET showed the highest level of antimicrobial action against all microorganisms (P <.001), and CH showed an intermediate level of action against S mutans and S aureus. Against C albicans and C glabrata, there was no significant difference among CH, CN, and WC. Conclusions: Although ET had a broader spectrum of antimicrobial action, CH showed promise as a denture cleanser.