Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process.

Fernanda Faot,Yuri Wanderley Cavalcanti,Wander José Da Silva,Luciana De Rezende Pinto,Altair Antoninha Del Bel Cury,Martinna De Mendonça E Bertolini

doi:10.1186/1472-6831-14-77

Fernanda Faot, Yuri Wanderley Cavalcanti + Show 4 more

Open Access

https://doi.org/10.1186/1472-6831-14-77

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Abstract

BackgroundIt is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface.MethodsC. albicans biofilms were developed for 72 h on PMMA resin specimens (n = 168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey’s Honestly Significant Difference (HSD) test (α = 0.05).ResultsImmediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p < 0.01). However, after 48 h, both CT groups (CT5 and CT8) showed biofilm recolonization (p < 0.01). Residual biofilm recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p < 0.01).ConclusionCitric acid denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this CT did not prevent biofilm recolonization.

Highlights

It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; the efficacy of citric acid denture cleansers is uncertain
48 h after treatments, C. albicans CFU counts were detected in the viable cell quantification, demonstrating that residual biofilms could recolonize the poly(methyl methacrylate) (PMMA) surface specimens
In the present study, we evaluated the efficacy of citric acid denture cleanser for removing or killing the C. albicans biofilm formed on the surface of PMMA specimens

Summary

Introduction

It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; the efficacy of citric acid denture cleansers is uncertain. Denture cleansing solutions have antimicrobial properties, as demonstrated by many studies [7,8,9,10,11,12]; none of these methods seem to effectively remove the biofilm and prevent recolonization on the denture surface [6,7] Another type of denture cleanser contains citric acid and is available as a concentrated solution, which can be used daily (1:5 dilution) or weekly (1:8 dilution) after proper dilution (as indicated by the manufacturer). This mechanism allows citric acid to break calcium bridges and subsequently disrupt the biofilm matrix, which may lead to anti-biofilm activity [14,15]

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