Efficacy of denture cleansers on Candida albicans adhesion and their effects on the properties of conventional, milled CAD/CAM, and 3D-printed denture bases.

OBJECTIVES: Evaluate the efficacy of denture cleaners on the adhesion of Candida albicans and their effects on the surface, optical, and mechanical properties of resins for conventional, milled, and 3D-printed denture bases. MATERIALS AND METHODS: A total of 240 resin samples were made, 120 for testing Candida albicans adhesion, optical stabilities (ΔE00), roughness (Ra), hydrophilicity (°), surface free energy (Owens-Wendt) and 120 samples for testing Candida albicans adhesion, surface microhardness (Knoop), flexural strength and modulus of elasticity in a three-point test, in which they were divided into 3 groups of denture resin (n = 40) and subdivided into 5 cleaners of dentures (n = 8). Data were evaluated by two-way ANOVA and Tukey's test for multiple comparisons (α = 0.05). RESULTS: Denture cleaners with an alkaline solution and dilute acid composition were those that showed the greatest effectiveness in reducing Candida albicans (P < 0.001), however 1% NaOCl significantly affected the properties of the resins (P < 0.05). Denture 3D-printed showed that the surface microhardness was significantly lower for all cleansers (P < 0.05). CONCLUSIONS: Listerine demonstrated superior efficacy in reducing Candida albicans with minimal effect on denture properties, whereas 1% NaOCl had a significant negative impact on the properties. The mechanical properties were significantly lower in 3D-printed resin than in other resins for all denture cleansers. CLINICAL RELEVANCE: Denture base materials are being sold to adapt to the CAD/CAM system, increasing the number of users of dentures manufactured with this system. Despite this, there is little investigation into denture cleaners regarding the adhesion capacity of microorganisms and the optical, surface and mechanical properties of dentures, thus requiring further investigation.

Anti-biofilm effectiveness of protocols for cleaning complete dentures in hospitalized patients: a randomized controlled trial.

BACKGROUND: Denture biofilm acts as a potential reservoir for respiratory pathogens, considerably increasing the risk of lung infections, specifically aspiration pneumonia, mainly 48h after hospital admission. The establishment of a straightforward, affordable, and applicable hygiene protocol in a hospital environment for the effective control of denture biofilm can be particularly useful to prevent respiratory infections or reduce the course of established lung disease. OBJECTIVES: To evaluate the anti-biofilm effectiveness of denture cleaning protocols in hospitalized patients. METHODOLOGY: The maxillary complete dentures (MCDs) of 340 hospitalized participants were randomly cleaned once using one of the following 17 protocols (n=20): brushing with distilled water, toothpaste, or neutral liquid soap (controls); immersion in chemical solutions (1% sodium hypochlorite, alkaline peroxide, 0.12% or 2% chlorhexidine digluconate), or microwave irradiation (650 W for 3 min) combined or not with brushing. Before and after the application of the protocols, the biofilm of the intaglio surface of the MCDs was evaluated using two methods: denture biofilm coverage area (%) and microbiological quantitative cultures on blood agar and Sabouraud Dextrose Agar (CFU/mL). Data were subjected to the Wilcoxon and Kruskal-Wallis tests (α=0.05). RESULTS: All 17 protocols significantly reduced the percentage area of denture biofilm and microbial and fungal load (P<0.05). The highest percentage reductions in the area of denture biofilm were observed for 1% hypochlorite solution with or without brushing and for 2% chlorhexidine solution and microwave irradiation only in association with brushing (P<0.05). The greatest reductions in microbial and fungal load were found for the groups that used solutions of 2% chlorhexidine and 1% hypochlorite and microwave irradiation, regardless of the association with brushing (P<0.05). CONCLUSIONS: A single immersion for 10 min in 1% sodium hypochlorite, even in the absence of brushing, proved to be a straightforward, rapid, low-cost, and effective protocol for cleaning the dentures of hospitalized patients.

Denture cleanser effect on resilient liners with distinct optical characteristics.

PURPOSE: To evaluate denture cleansing solutions regarding the surface roughness and color stability of two resilient liners with distinct optical characteristics used for the maximum recommended period of use. METHODS: The specimens of each resilient liner, transparent and white, were randomly distributed into groups (n= 15) of a daily 20-minute immersion simulation of 0.25%, 0.5% and 1% sodium hypochlorite (SH) and 4% acetic acid solutions. Surface roughness (Ra) and color stability (ΔE CIELab formula and NBS systems) were measured after 7, 14, 21, 30, 60, 90, 180, and 270 days. The factors of variations analyzed were material, solutions, and time of immersion. Statistical analysis used three-way ANOVA and Tukey tests (Ra), and repeated measure ANOVA (ΔE and NBS systems), P< 0.05. RESULTS: For Ra analysis, the variations occurred regardless of time and solution, as the white liner showed the greatest changes (P< 0.001). Regarding interactions between solution and time, in the period of 21 days until 270 days, Ra was equivalent for all solutions (P= 0.001). ΔE analysis showed a difference between solutions (P= 0.000) and interaction between time and solution (P= 0.000). For the transparent liner, the greatest changes were found for 1% SH after 60 days, however, at 270 days there was a color change equivalence with 0.5% SH, while 4% acetic acid solution showed intermediate values. For the white liner, 1% SH showed the highest color changes for all evaluated times, and the other evaluated solutions were similar after 270 days. For both resilient liners, 0.25% SH showed the smallest changes for the evaluated properties. CLINICAL SIGNIFICANCE: The changes found were dependent on the concentration of the solution used, as well as the length of exposure to the solution. In addition, the white resilient liner showed to be less susceptible to color changes. For both resilient liners, 0.25% sodium hypochlorite showed the least changes for the evaluated properties.

Effect of effervescent tablets on removable partial denture hygiene.

PURPOSE: To evaluate the effectiveness of five alkaline peroxide-based effervescent tablets in reducing both biofilms and the food layer adhered on the cobalt-chromium surface. METHODS: Cobalt-chromium metal alloy specimens were contaminated with Candida albicans, Candida glabrata, Streptococcus mutans and Staphylococcus aureus. After biofilm maturation, the specimens were immersed in Polident 3 Minute, Polident for Partials, Efferdent, Steradent, Corega Tabs or distilled water (control). Residual biofilm rates were determined by colony forming units counts and biofilm biomass. In parallel, to investigate the denture cleaning capability of effervescent tablets, artificially contaminated removable partial dentures were treated with each cleanser. Data were analyzed by Kruskal-Wallis followed by Dunn post hoc test or ANOVA followed by Tukey post hoc test (α= 0.05). RESULTS: None of the hygiene solutions reduced C. albicans biofilm. Efferdent and Corega Tabs promoted reduction of C. glabrata biofilm, while Steradent was favorable against S. aureus biofilm. For S. mutans, lower biofilm rates were observed after immersion in Polident for Partials and Steradent. The effervescent tablets showed good cleaning performance, removing an artificial layer with carbohydrates, proteins, and fats, however, they were not effective in removing aggregated mature biofilm. CLINICAL SIGNIFICANCE: The different effervescent tablets presented favorable antimicrobial activity against C. glabrata, S. mutans and S. aureus on cobalt-chromium surfaces and showed cleaning capability. However, for an appropriate biofilm control, a complementary method should be evaluated since none of the peroxide-based solutions reduced C. albicans biofilms or substantially removed aggregated biofilm.

Do denture cleansers influence the surface roughness and adhesion and biofilm formation of Candida albicans on acrylic resin? Systematic review and meta-analysis.

PURPOSE: To evaluate the influence of denture cleansers on the surface roughness, Candida albicans adhesion, and biofilm formation on denture base acrylic resins. STUDY SELECTION: Electronic databases and gray literature were searched using an individual search strategy. In vitro studies that evaluated the effects of immersion in denture cleansers on the surface roughness (µm) and antimicrobial activity (CFU/mL) on samples of heat-polymerized denture base acrylic resins were included. RESULTS: After screening, 17 studies were included, and a qualitative synthesis was performed. After assessing the risk of bias, only nine studies were included in the meta-analysis. The meta-analysis results showed that the evaluated solutions (0.5% sodium hypochlorite, 1% sodium hypochlorite, alkaline peroxide, and natural substances) did not influence the roughness of the acrylic resin. However, in the qualitative analysis, it was not possible to confirm an association between roughness and C. albicans adhesion and biofilm formation on the acrylic resin samples. CONCLUSION: Denture cleansers did not affect the surface roughness of denture base acrylic resins.

Effects of long-term cinnamaldehyde immersion on the surface roughness and color of heat-polymerized denture base resin.

STATEMENT OF PROBLEM: Cinnamaldehyde has been successfully used for the short-term disinfection of dentures; however, its long-term effects on the surface and color properties of denture base materials remain unknown. PURPOSE: The purpose of this in vitro study was to evaluate the effects of simulated immersion in cinnamaldehyde for up to 5 years on the surface roughness and color parameters of a heat-polymerized denture resin. MATERIAL AND METHODS: Eighty Ø10×5-mm disk-shaped specimens were prepared from microwave heat-polymerized polymethylmethacrylate (PMMA) and immersed in 4 solutions (n=20): TW-tap water (control), SH - 0.5% sodium hypochlorite, PX-alkaline peroxide, and CA-cinnamaldehyde (27 µg/mL). The immersion protocol simulated 104 cycles (3.5 months), 913 cycles (2.5 years), and 1825 immersion cycles (5 years) of a daily immersion cleaning protocol, with immersion times ranging from 10 to 20-minutes. Surface roughness (Sa) and the color parameters of CIELab (L∗ a∗ b∗, ΔEab), CIEDE2000 (ΔE00), and the National Bureau of Standards (NBS) were analyzed at baseline (t=0) and after the immersion cycles. The data were analyzed by 2-way analysis of variance (ANOVA) for repeated measures and the Tukey post hoc test (α=.01). RESULTS: Sa was significantly increased in all groups after 1825 cycles compared with baseline (P<.01), regardless of the solution. Only the time factor significantly affected ΔEab, ΔE00, and NBS parameters, which were below the perceptibility and acceptability thresholds. After a simulated 5-year immersion, the surface roughness and color values of CA-treated specimens were not statistically different from those of the other groups (P>.01). CONCLUSIONS: Cinnamaldehyde solution (27 µg/mL) produced minor effects on the surface roughness and color parameters of a heat-polymerized denture base resin similar to those of 0.5% sodium hypochlorite and alkaline peroxide after a 5-year simulated immersion.

Effect of local hygiene protocols on denture-related stomatitis, biofilm, microbial load, and odor: A randomized controlled trial.

STATEMENT OF PROBLEM: Denture stomatitis affects complete denture wearers and is frequently treated with antifungals drugs, as well as treating the denture with sodium hypochlorite. Whether the limitations of these treatments can be overcome with local hygiene protocols that do not damage the denture materials or adversely affect the patient is unclear. PURPOSE: The purpose of this randomized controlled trial was to evaluate the effect of denture hygiene protocols on complete denture wearers with denture stomatitis. MATERIAL AND METHODS: For this randomized, double-blind controlled clinical trial, 108 participants were assigned to parallel groups: 0.25% sodium hypochlorite (positive control) 0.15% Triclosan, denture cleaning tablets, or denture cleaning tablets plus gingival cleaning tablets. The participants were instructed to brush the dentures and the palate and immerse the denture in the solutions. The outcomes of denture stomatitis remission, biofilm removal, decrease of microbial load (colony-forming units), and odor level of the mouth and denture were measured at baseline and after 10 days. Descriptive analyses were used for sociodemographic characterization of the participants; the Pearson chi-square test was used to compare participant frequency with different degrees of denture stomatitis. The data were not normally distributed (Shapiro-Wilks test) or homogeneous (Levene test). So, the Kruskal-Wallis and Dunn post hoc tests and Wilcoxon test were used to compare the effects of solutions and time on the variables (α=.05). RESULTS: The frequency of the highest to lowest denture stomatitis scores was significantly different for the 0.15% Triclosan and denture cleaning tablets groups. No significant difference was found among the groups in terms of denture stomatitis scores, biofilm, or colony-forming unit count of Candida spp. or C. albicans and S. mutans; a significant reduction was found in these parameters. The 0.25% sodium hypochlorite and 0.15% Triclosan treatments caused a significant reduction in Gram-negative microorganisms; these 2 protocols, and the denture cleaning tablets showed a significant reduction in Staphylococcus spp.; all protocols had similar effects. Only the S. mutans count of the palate decreased after 10 days. The odor level of the mouth and the denture was not significantly different (P=.778). CONCLUSIONS: The evaluated protocols can be recommended for the hygiene of complete dentures, since they were effective for all the variables studied.

Complete denture hygiene solutions: antibiofilm activity and effects on physical and mechanical properties of acrylic resin.

BACKGROUND: Appropriated denture hygiene is a predictive factor for longevity of rehabilitation treatment and maintenance of the oral mucosal health. Although, disinfectant solutions are commonly used as denture cleansers, the impact of these solutions on acrylic resin-based dentures remain unclear. OBJECTIVE: To evaluate, in vitro, the antibiofilm activity of complete denture hygiene solutions and their effects on physical and mechanical properties of acrylic resin. METHODOLOGY: For antibiofilm activity measurement acrylic resin specimens were contaminated with Candida albicans, Candida glabrata and Streptococcus mutans. After biofilm growth, the specimens were assigned to the hygiene solutions: Distilled water (Control); 0.2% Sodium hypochlorite (SH); Efferdent Power Clean Crystals (EPC) and 6.25% Ricinus communis (RC). The viability of microorganisms was evaluated by agar plate counts. In parallel, physical, and mechanical properties of the acrylic resin were evaluated after simulating a 5-year period of daily immersion in the previously mentioned solutions. The changes in surface roughness, color, microhardness, flexural strength, impact strength, sorption and solubility were evaluated. Data were compared by ANOVA followed by the Tukey test or Kruskal-Wallis followed by the Dunn test depending on the distribution (α=0.05). RESULTS: Regarding antibiofilm action, SH eliminated all microorganisms while EPC and RC exhibited moderate action against S. mutans (p=0.001) and C. glabrata (p<0.001), respectively. Relative to effects on the physical and mechanical properties of the acrylic resin, RC led to higher values of color change (p=0.030), hardness (p<0.001), surface roughness (p=0.006) and flexural strength (p<0.001). Moreover, RC induced the highest values of changes in solubility (p<0.001). EPC promoted greater changes in surface morphology, whereas immersion in SH retained the initial appearance of the acrylic resin surface. All hygiene solutions reduced the impact strength (p<0.05). CONCLUSION: SH presented the most effective antibiofilm activity. In addition, changes on properties were observed after immersion in RC, which were considered within acceptable limits.

Antimicrobial activity of effervescent denture tablets on multispecies biofilms.

PURPOSE: To investigate the impact of peroxide-based solutions in reducing viability and metabolic activity of multispecies biofilms on denture base acrylic resin surfaces and for removing them from these surfaces. BACKGROUND: Denture cleansers are effective in reducing monospecies biofilm; however, studies evaluating their action on multispecies biofilms are scarce. MATERIALS AND METHODS: Sixty-nine denture base acrylic resin specimens (Ø 15 × 3 mm) were sterilised then contaminated with Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa to form multispecies biofilms. Biofilms were grown for 24 hours; subsequently, specimens were immersed in three different cleansing solutions (n = 9): nitradine (NI), fixodent (FX) and phosphate-buffered saline (Control), according to the respective manufacturer's instructions. After applying the hygiene protocols, viability of microorganisms was evaluated by counting colony-forming units and assessing metabolic activity. Moreover, biofilm removal capacity was estimated based on extension of cell-covered areas visualised in fluorescent microscopy micrographics. RESULTS: Microbial counts were solution-dependent; NI was effective against all microorganisms (P < .05). FX exhibited moderate antimicrobial action, reducing P aeruginosa (P < .05) and S aureus (P < .05) viability by approximately 2 logs. Both peroxide-based solutions reduced metabolic activity (P < .001) and biofilm-covered areas on specimen surfaces (P < .001). CONCLUSION: Under the experimental conditions tested, these results demonstrated that peroxide-based solutions had favourable antimicrobial activity but promoted no broad elimination of aggregated multispecies biofilm. NI might be more suitable as complementary chemical agent for controlling multispecies denture biofilm.

Complete denture hygiene solutions: antibiofilm activity and effects on physical and mechanical properties of acrylic resin

Abstract Appropriated denture hygiene is a predictive factor for longevity of rehabilitation treatment and maintenance of the oral mucosal health. Although, disinfectant solutions are commonly used as denture cleansers, the impact of these solutions on acrylic resin-based dentures remain unclear. Objective To evaluate, in vitro, the antibiofilm activity of complete denture hygiene solutions and their effects on physical and mechanical properties of acrylic resin. Methodology For antibiofilm activity measurement acrylic resin specimens were contaminated with Candida albicans, Candida glabrata and Streptococcus mutans. After biofilm growth, the specimens were assigned to the hygiene solutions: Distilled water (Control); 0.2% Sodium hypochlorite (SH); Efferdent Power Clean Crystals (EPC) and 6.25% Ricinus communis (RC). The viability of microorganisms was evaluated by agar plate counts. In parallel, physical, and mechanical properties of the acrylic resin were evaluated after simulating a 5-year period of daily immersion in the previously mentioned solutions. The changes in surface roughness, color, microhardness, flexural strength, impact strength, sorption and solubility were evaluated. Data were compared by ANOVA followed by the Tukey test or Kruskal-Wallis followed by the Dunn test depending on the distribution (α=0.05). Results Regarding antibiofilm action, SH eliminated all microorganisms while EPC and RC exhibited moderate action against S. mutans (p=0.001) and C. glabrata (p<0.001), respectively. Relative to effects on the physical and mechanical properties of the acrylic resin, RC led to higher values of color change (p=0.030), hardness (p<0.001), surface roughness (p=0.006) and flexural strength (p<0.001). Moreover, RC induced the highest values of changes in solubility (p<0.001). EPC promoted greater changes in surface morphology, whereas immersion in SH retained the initial appearance of the acrylic resin surface. All hygiene solutions reduced the impact strength (p<0.05). Conclusion SH presented the most effective antibiofilm activity. In addition, changes on properties were observed after immersion in RC, which were considered within acceptable limits.

Determination of the effective anticandidal concentration of denture cleanser tablets on some denture base resins.

Although the effectiveness of chemical cleansing against Candida albicans biofilm has been shown, the effective concentration of denture cleanser tablets has not been studied. The aim of this study was to assess the effect of three denture materials against Candida albicans biofilm and to determine effective concentrations of denture cleanser tablets. The surface-roughness of Acron-hi™, QC-20™ and Deflex™ (n=45 per resin) resins was standardized by using a profilometer and their contact angle or surface free energy was calculated. C. albicans biofilm was formed on all three resins and were treated with Polident 3 min™, Corega™ and Fittydent™ cleanser solutions at various concentrations and both resin-biofilm and cleanser-biofilm interest were determined by using a MTT protocol according to the European Committee on Antimicrobial Susceptibility Testing's antifungal susceptibility testing (AFST-EUCAST). Scanning electron microscopy was used to compare the efficacy of different resin materials against C. albicans biofilm. Anticandidal activity and surface free energy statistical parameters were calculated by using 3-way and 1-way ANOVA, respectively (p<0.05). Polident 3 min™ and Corega™ tablets significantly inhibited (p<0.05) the proliferation of C. albicans against all denture resins at 27-37 mg/mL. Scanning electron microscopy results indicated that there was no significant difference among resin specimens regarding biofilm formation on dentures. We failed to find a significant relationship between surface free energy and the anticandidal effect of resin types. However, the polarity value of the resins was statistically associated with their anticandidal activity. The polarity of the resins, the concentrations of tablets and the chemical content of the cleanser may directly affect C. albicans biofilm formations. Polident 3 min™ and Corega™ tablets should be suggested for patients who use any denture resin types, whereas the Fittydent™ tablet should only be proposed for those who use Deflex™, when two tablets are dropped into 150 mL water.

In Vitro Effectiveness of a Terpenic Denture Cleanser on Old Biofilm Surfaces.

PURPOSE: To assess the effects of terpenic denture cleanser on denture biofilm removal using scanning electron microscopy (SEM). MATERIALS AND METHODS: The internal surface biofilm of four maxillary dentures was elucidated with Caristop-revelador Dual Tone, and 40 blue-stained specimens (0.6 cm × 0.4 cm × 2 mm) were obtained. These specimens were randomly assigned to one of the following four groups of 10 specimens each: control, Eci Clean, Fitty Dent, and terpenic denture cleanser. The period of immersion in each solution was 12 hours. Biofilm removal was evaluated using SEM, and morphologically varying areas of the SEM images were quantified with Imaris software. The data were analyzed using Kolmogorov-Smirnov, t-tests, ANOVA, and Tamhane's tests (p = 0.05). RESULTS: Data revealed that terpenic denture cleanser removed significantly more biofilm than any other treatment examined in this study. The t-tests revealed significant differences in the clean area that resulted from the use of the terpenic cleanser compared with the clean area that resulted from the use of Eci Clean (p = 0.013). Fitty Dent was the least effective and left dirty acrylic resin. The average areas with few removed layers were 59.3%, 43.3%, and 9.5% in Fitty Dent, Eci Clean, and terpenic cleanser groups, respectively. Tamhane's tests indicated that the Eci Clean and Fitty Dent groups were significantly different from the 0.5% terpenic cleanser group (p = 0.008). CONCLUSION: The terpenic denture cleanser was effective in removing denture biofilm.

Determination of the effective anticandidal concentration of denture cleanser tablets on some denture base resins

Abstract Objective Although the effectiveness of chemical cleansing against Candida albicans biofilm has been shown, the effective concentration of denture cleanser tablets has not been studied. The aim of this study was to assess the effect of three denture materials against Candida albicans biofilm and to determine effective concentrations of denture cleanser tablets. Material and methods The surface-roughness of Acron-hi™, QC-20™ and Deflex™ (n=45 per resin) resins was standardized by using a profilometer and their contact angle or surface free energy was calculated. C. albicans biofilm was formed on all three resins and were treated with Polident 3 min™, Corega™ and Fittydent™ cleanser solutions at various concentrations and both resin-biofilm and cleanser-biofilm interest were determined by using a MTT protocol according to the European Committee on Antimicrobial Susceptibility Testing's antifungal susceptibility testing (AFST-EUCAST). Scanning electron microscopy was used to compare the efficacy of different resin materials against C. albicans biofilm. Anticandidal activity and surface free energy statistical parameters were calculated by using 3-way and 1-way ANOVA, respectively (p<0.05). Results Polident 3 min™ and Corega™ tablets significantly inhibited (p<0.05) the proliferation of C. albicans against all denture resins at 27-37 mg/mL. Scanning electron microscopy results indicated that there was no significant difference among resin specimens regarding biofilm formation on dentures. We failed to find a significant relationship between surface free energy and the anticandidal effect of resin types. However, the polarity value of the resins was statistically associated with their anticandidal activity. Conclusions The polarity of the resins, the concentrations of tablets and the chemical content of the cleanser may directly affect C. albicans biofilm formations. Polident 3 min™ and Corega™ tablets should be suggested for patients who use any denture resin types, whereas the Fittydent™ tablet should only be proposed for those who use Deflex™, when two tablets are dropped into 150 mL water.

Antimicrobial action and long-term effect of overnight denture cleansers.

PURPOSE: To evaluate two denture cleansers for overnight soaking (0.5% sodium hypochlorite and peroxide alkaline) regarding efficacy against Candida spp. biofilms (randomized clinical trial) and their effects on the physical properties of a denture base acrylic resin simulating a period of 5 years of use (laboratory study). The Candida spp. were identified and their resistance to main antifungal agents was evaluated. METHODS: 32 complete denture wearers were instructed to brush their dentures three times a day and to soak them (≥8 hours) in: control - water (C); alkaline peroxide (AP); or 0.5% sodium hypochlorite (SH). According to a randomized sequence, each solution was used for three alternate periods of 7 days. The antimicrobial action was performed by counting the colony forming units (CFU) of Candida spp. For collection of the biofilm, each upper complete denture was placed in a Petri dish, the internal surface was brushed (Tek brush) with saline solution for 2 minutes and the suspension was transferred to a test tube. After dilutions (10 0 to 10-3), aliquots of 50 µL were seeded inside Petri dishes containing Candida Chromagar. After incubation, the colonies were counted and the values of CFU/mL calculated. Data were transformed in log10 (CFU +1) and analyzed by the Friedman test (α= 0.05) followed by Wilcoxon and Bonferroni tests (α= 0.05). Each of the different species identified perfunctorily has been confirmed through the identification of yeasts kit. The resistance to antifungal agents (amphotericin B, nystatin, flucytosine, econazole, ketoconazole, miconazole and fluconazole) was also evaluated. Adverse effects were estimated on heat-polymerized resin specimens, simulating a 5-year period of overnight use. Acrylic resin specimens were randomly distributed into three groups: C: Control (distilled water); AP: alkaline peroxide; and SH: 0.5% sodium hypochlorite. Color change, surface roughness and flexural strength were evaluated at baseline and after immersion procedures. Data were compared by Kruskall-Wallis followed by Dunn's test (color change and surface roughness) and one-way ANOVA (flexural strength) (α= 0.05). RESULTS: There was a reduction of Candida spp. counts after using both solutions (AP and SH). The Candida spp. most often isolated was C. albicans, followed by the C. glabrata. Only 24.7% of isolate strains were resistant to at least one of the tested antifungals, highlighting azole compounds. Immersion in AP [ 5.73 (5.45-5.91)] caused significantly higher color change, with lower ΔE values for C [1.12 (1.15-1.37) ] followed by SH [3.70 (3.51-3.98) ]. The NBS values were classified as "slight" for C (1.12) group and " considerable" for AP (5.27) and SH (3.40). No solution altered surface roughness significantly. Flexural strength (in MPa) was significantly lower for C (64.59), AP (63.96 ± 12.98) and SH (62.84 ± 8.62) when compared to a group without any immersion (109.12 ± 8.37). CLINICAL SIGNIFICANCE: Both solutions tested presented antimicrobial action against Candida spp. and may be useful for denture biofilm control, but should be used with caution as an overnight immersion solution since they may damage denture bases in the long-term. Candida was most frequently isolated at baseline and after using the products. Only 24.7% of isolate strains were resistant to at least one of the tested antifungals, especially with azole compounds.

Antimicrobial activity of complete denture cleanser solutions based on sodium hypochlorite and Ricinus communis: a randomized clinical study

ABSTRACT To preserve oral health and to maintain the prosthetic devices, it is important not only to improve the properties of commonly known hygiene products, but also to investigate new materials with antimicrobial action. Objectives This study evaluated the antimicrobial activity of sodium hypochlorite (0.25% and 0.50%) and 10% Ricinus communis’ solutions against specific microorganisms. Material and Methods Sixty four maxillary complete denture wearers were instructed to brush their dentures three times a day and to soak them (20 min/day) in the solutions: SH1: 0.25% sodium hypochlorite; SH2: 0.5% sodium hypochlorite; RC: 10% R. communis oil; and C: 0.85% saline (control). The solutions were used for 7 days in a randomized sequence. Following each period of use, there was a 1-week washout period. Antimicrobial activity was determined by Colony Forming Units (CFU) counts of Streptococcus mutans, Candida spp., and gram-negative microorganisms. For collecting biofilm, the internal surface of maxillary dentures was brushed with saline solution, and biofilm suspension obtained. After dilutions (100 - 10-3), aliquots were seeded in Mitis salivarius, CHROMagar Candida®, and MacConkey agar for detecting S. mutans, Candida spp., or gram-negative microorganisms, respectively. After incubation, colonies were counted, and CFU/mL values were calculated. Then, transformation - log10 (CFU+1) - data were analyzed using the Friedman test (α=0.05). Results showed significant differences between the solutions (p<0.001). Results All three solutions showed antimicrobial activity against S. mutans. Against Candida spp., RC and SH1 solutions showed similar effect while SH2 showed superior activity. SH1 and SH2 solutions showed antimicrobial action against gram-negative microorganisms. The Candida species most frequently isolated was C. albicans, followed by C. tropicalis and C. glabrata. Conclusions The 0.5% sodium hypochlorite solution was the most effective and might be used to control denture biofilm. C. albicans was the most frequently isolated Candida sp.

Antimicrobial action of sodium hypochlorite and castor oil solutions for denture cleaning - in vitro evaluation.

The objective of this in vitro study was to evaluate the antimicrobial action of sodium hypochlorite (0.25% and 0.50%) and 10% castor oil solutions against specific microorganisms, by counting Colony Forming Units (CFU) of clinically important bacteria and Candida species. Acrylic resin specimens (n = 320; Lucitone 550) were obtained from square metal matrices (10 x 10 x 2 mm), sterilized by microwave (650W, for 6 minutes) and contaminated by Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Bacillus subtilis, Escherichia coli, Streptococcus mutans, Enterococcus faecalis and Candida glabrata. The specimens were immersed for 20 minutes in one of the following hygiene solutions (n = 10/each): A - 0.25% Sodium hypochlorite; B - 0.5% Sodium hypochlorite; C - 10% Castor oil solution; and D (Control) - saline. Adhered cells were suspended and inoculated into a selective solid medium (37ºC for 24 h). The Student's t-test (α = 0.05) was performed to compare log10(CFU+1)/mL between Groups C and D. The results showed that sodium hypochlorite (0.25% and 0.5%) completely eliminated all detectable microorganisms. The castor oil solution eliminated B. subtilis and reduced counts for other strains. Differences between C and D were significant (p < 0.05) for all species except for E. faecalis. Both sodium hypochlorite solutions (0.25% and 0.5%) were effective in eliminating all microorganisms evaluated, and may be useful as cleaning solutions for complete dentures. The castor oil solution provided moderate efficacy and performed differently on the tested species, with the strongest effect on B. subtilis and with non-significant action on E. faecalis.

Candida albicans adherence to denture base material: chemical disinfection and the effect of acquired salivary pellicle formation.

PURPOSE: The aim of this study was to evaluate the effect of 1% sodium hypochlorite (H1%) and 4% chlorhexidine gluconate (CG4%) on the adhesion of Candida albicans to denture base acrylic resins, as well as to verify the effect of the acquired salivary pellicle (ASP) formation on this process. MATERIALS AND METHODS: A total of 300 acrylic specimens were immersed in distilled water (control) (n = 100), H1% (n = 100), or CG4% (n = 100) for 30 days. Twenty specimens were used in each experimental period (0, 1, 7, 15, 30 days). At the end of disinfection testing periods, 10 specimens of each group were exposed to human whole saliva to simulate ASP formation, and then all specimens were incubated with C. albicans ATTC 90028. Microorganism adhesion was analyzed by fluorescence microscopy, after staining with Acridine orange. RESULTS: In the 30(th) disinfection cycle in relation to baseline, the H1% or CG4%, without ASP formation, reduced the C. albicans adhesion by approximately 80%; however, with ASP, this reduction after disinfection with H1% was higher (88%). The presence of ASP resulted in higher reduction of adhered fungal cells in comparison to resin without ASP, at the 1(st) H1% or CG4% disinfection cycle, as well as at 30(th) H1% disinfection cycles. CONCLUSIONS: Our results suggest that the presence of saliva might influence the adhesion of C. albicans and improve the effectiveness of methods to reduce fungal adhesion.

Antimicrobial activity of complete denture cleanser solutions based on sodium hypochlorite and Ricinus communis - a randomized clinical study.

UNLABELLED: To preserve oral health and to maintain the prosthetic devices, it is important not only to improve the properties of commonly known hygiene products, but also to investigate new materials with antimicrobial action. Objectives This study evaluated the antimicrobial activity of sodium hypochlorite (0.25% and 0.50%) and 10% Ricinus communis' solutions against specific microorganisms. MATERIAL AND METHODS: Sixty four maxillary complete denture wearers were instructed to brush their dentures three times a day and to soak them (20 min/day) in the solutions: SH1: 0.25% sodium hypochlorite; SH2: 0.5% sodium hypochlorite; RC: 10% R. communis oil; and C: 0.85% saline (control). The solutions were used for 7 days in a randomized sequence. Following each period of use, there was a 1-week washout period. Antimicrobial activity was determined by Colony Forming Units (CFU) counts of Streptococcus mutans, Candida spp., and gram-negative microorganisms. For collecting biofilm, the internal surface of maxillary dentures was brushed with saline solution, and biofilm suspension obtained. After dilutions (100 - 10-3), aliquots were seeded in Mitis salivarius, CHROMagar Candida, and MacConkey agar for detecting S. mutans, Candida spp., or gram-negative microorganisms, respectively. After incubation, colonies were counted, and CFU/mL values were calculated. Then, transformation - log10 (CFU+1) - data were analyzed using the Friedman test (α=0.05). Results showed significant differences between the solutions (p<0.001). RESULTS: All three solutions showed antimicrobial activity against S. mutans. Against Candida spp., RC and SH1 solutions showed similar effect while SH2 showed superior activity. SH1 and SH2 solutions showed antimicrobial action against gram-negative microorganisms. The Candida species most frequently isolated was C. albicans, followed by C. tropicalis and C. glabrata. CONCLUSIONS: The 0.5% sodium hypochlorite solution was the most effective and might be used to control denture biofilm. C. albicans was the most frequently isolated Candida sp.