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STATEMENT OF PROBLEM: The optimal disinfection protocol that controls adverse effects and promotes effective antimicrobial action on removable prostheses is unclear. PURPOSE: This in vitro study investigated the effect of disinfectant solutions on the biological, physical, mechanical, and chemical properties of removable prosthesis materials. MATERIAL AND METHODS: Specimens of polymethyl methacrylate (PMMA) and cobalt chromium (Co-Cr) alloy were immersed in distilled water (PMMA) or artificial saliva (Co-Cr) as the control and in 0.25% sodium hypochlorite (NaOCl0.25%), 0.5% chloramine T (CT0.5%), and 0.15% Triclosan (TR0.15%). The antibiofilm activity was evaluated by microbial load and cell metabolisms of the mixed biofilm. Physical (color change, sorption, solubility, and surface roughness), mechanical (hardness, flexural, and impact strength), and chemical (corrosion) properties were analyzed before and after simulating a 5-year immersion. Laser confocal microscopy, scanning electron microscopy (SEM), and dispersive energy spectroscopy (EDS) complemented the analyses. The data were analyzed by using the Mann-Whitney U test, Kruskal-Wallis with Dunn posttests, 1-way ANOVA, and repeated measures ANOVA (α=.05). RESULTS: All solutions were effective against bacteria, but only NaOCl0.25% eliminated Candida spp. TR0.15%, and CT0.5% increased cell metabolisms. For interaction (time and solution), there was a reduction in PMMA hardness in the control and TR0.15%. Color, sorption, solubility, and flexural strength did not change. CT0.5% and TR0.15% were similar for impact resistance. CT0.5% caused the lowest roughness. NaOCl0.25% showed the greatest corrosive potential. Dark spots were seen under SEM in Co-Cr stored with NaOCl0.25% and TR0.15%. EDS indicated different proportions of oxygen, cobalt, chromium, and molybdenum. CONCLUSIONS: NaOCl0.25% had the best antimicrobial action. CT0.5% and TR0.15% have potential. Hardness and roughness changes were clinically acceptable, and the other properties remained unchanged. All the solutions caused color changes. NaOCl0.25% was unsatisfactory for use with Co-Cr, CT0.5% was intermediate, and TR0.15% was suitable.

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PURPOSE: To evaluate in situ the influence of sweat, oil, sunscreen, and disinfectant solution on the color stability, hardness, and roughness of elastomer for facial prostheses. MATERIALS AND METHODS: Standardized and intrinsically pigmented specimens remained in contact with human skin from the same person for 30 days, considering exposures (n = 36 per group), absent of exposition (Control, C); sweat and oiliness contact (SO); sweat and oiliness associated with sunscreen (SOS); 0.12% chlorhexidine digluconate immersion (CD0.12%); and all agents exposed (SOSCD). The main variables were color change (CIELab and National Standard Bureau system, NBS), Shore A hardness, and surface roughness, measured at baseline and 30 days. Qualitative analyses were performed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The data were analyzed by Kruskal-Wallis tests (color) and two-way ANOVA (hardness and roughness) with Sidak post-test (α = 0.05). RESULTS: CD0.12% (1.54 ± 0.49) and SOSCD (2.10 ± 1.03) had similar effects and caused the smallest color changes, considered mild and noticeable (NBS), respectively. SOS promoted the greatest color change (6.99 ± 1.43, NBS: large) and hardness (17.97 ± 0.56); SOS promoted intermediate roughness (3.48 ± 1.05) between SOSCD (2.25 ± 0.53), and two similar groups: C (4.46 ± 0.95), and CD0.12% (4.39 ± 1.26). The qualitative analysis showed an irregular, dense, dry, and whitish layer on the surface of the specimens exposed to sunscreen, which was reduced when in contact with 0.12% chlorhexidine digluconate. CONCLUSIONS: Endogenous and exogenous factors are capable of altering elastomer properties. The 0.12% chlorhexidine digluconate minimized the changes caused by sweat, oil, and sunscreen.

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Specific products containing natural resources can contribute to the innovation of complete denture hygiene. OBJECTIVE: To conduct an in vitro evaluation of experimental dentifrices containing essential oils of Bowdichia virgilioides Kunth (BvK), Copaifera officinalis (Co), Eucalyptus citriodora (Ec), Melaleuca alternifolia (Ma) and Pinus strobus (Ps) at 1%. METHODOLOGY: The variables evaluated were organoleptic and physicochemical characteristics, abrasiveness (mechanical brushing machine) simulating 2.5 years, and microbial load (Colony Forming Units - CFU/mL), metabolic activity (XTT assay) and cell viability (Live/Dead® BacLight™ kit) of the multispecies biofilm (Streptococcus mutans: Sm, Staphylococcus aureus: Sa, Candida albicans: Ca and Candida glabrata: Cg). Specimens of heat-polymerized acrylic resins (n=256) (n=96 specimens for abrasiveness, n=72 for microbial load count, n=72 for biofilm metabolic activity, n=16 for cell viability and total biofilm quantification) with formed biofilm were divided into eight groups for manual brushing (20 seconds) with a dental brush and distilled water (NC: negative control), Trihydral (PC: positive control), placebo (Pl), BvK, Co, Ec, Ma or Ps. After brushing, the specimens were washed with PBS and immersed in Letheen Broth medium, and the suspension was sown in solid specific medium. The organoleptic characteristics were presented by descriptive analysis. The values of density, pH, consistency and viscosity were presented in a table. The data were analyzed with the Wald test in a generalized linear model, followed by the Kruskal-Wallis test, Dunn's test (mass change) and the Bonferroni test (UFC and XTT). The Wald test in Generalized Estimating Equations and the Bonferroni test were used to analyze cell viability. RESULTS: All dentifrices showed stable organoleptic characteristics and adequate physicochemical properties. CN, Ec, Ps, Pl and PC showed low abrasiveness. There was a significant difference between the groups (p<0.001) for microbial load, metabolic activity and biofilm viability. CONCLUSIONS: It was concluded that the BvK, Ec and Ps dentifrices are useful for cleaning complete dentures, as they have antimicrobial activity against biofilm. The dentifrices containing Bowdichia virgilioides Kunth showed medium abrasiveness and should be used with caution.

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OBJECTIVE: This study evaluated the surface roughness, wettability and adhesion of multispecies biofilms (Candida albicans, Staphylococcus aureus and Streptococcus mutans) on 3D-printed resins for complete denture bases and teeth compared to conventional resins (heat-polymerized acrylic resin; artificial pre-fabricated teeth). METHODOLOGY: Circular specimens (n=39; 6.0 mm Ø × 2.0 mm) of each group were subjected to roughness (n=30), wettability (n=30) and biofilm adhesion (n=9) tests. Three roughness measurements were taken by laser confocal microscopy and a mean value was calculated. Wettability was evaluated by the contact angle of sessile drop method, considering the mean of the three evaluations per specimen. In parallel, microorganism adhesion to resin surfaces was evaluated using a multispecies biofilm model. Microbial load was evaluated by determining the number of Colony Forming Units (CFU/mL) and by scanning electron microscopy (SEM). Data were subjected to the Wald test in a generalized linear model with multiple comparisons and Bonferroni adjustment, as well as two-way ANOVA (α=5%). RESULTS: The roughness of the conventional base resin (0.01±0.04) was lower than that of the conventional tooth (0.14±0.04) (p=0.023) and 3D-printed base (0.18±0.08) (p<0.001). For wettability, conventional resin (84.20±5.57) showed a higher contact angle than the 3D-printed resin (60.58±6.18) (p<0.001). Higher microbial loads of S. mutans (p=0.023) and S. aureus (p=0.010) were observed on the surface of the conventional resin (S. mutans: 5.48±1.55; S. aureus: 7.01±0.57) compared to the 3D-printed resin (S. mutans: 4.11±1.96; S. aureus: 6.42±0.78). The adhesion of C. albicans was not affected by surface characteristics. The conventional base resin showed less roughness than the conventional dental resin and the printed base resin. CONCLUSION: The 3D-printed resins for base and tooth showed less hydrophobicity and less adhesion of S. mutans and S. aureus than conventional resins.

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Abstract Specific products containing natural resources can contribute to the innovation of complete denture hygiene. Objective: To conduct an in vitro evaluation of experimental dentifrices containing essential oils of Bowdichia virgilioides Kunth (BvK), Copaifera officinalis (Co), Eucalyptus citriodora (Ec), Melaleuca alternifolia (Ma) and Pinus strobus (Ps) at 1%. Methodology: The variables evaluated were organoleptic and physicochemical characteristics, abrasiveness (mechanical brushing machine) simulating 2.5 years, and microbial load (Colony Forming Units - CFU/mL), metabolic activity (XTT assay) and cell viability (Live/Dead® BacLight™ kit) of the multispecies biofilm (Streptococcus mutans: Sm, Staphylococcus aureus: Sa, Candida albicans: Ca and Candida glabrata: Cg). Specimens of heat-polymerized acrylic resins (n=256) (n=96 specimens for abrasiveness, n=72 for microbial load count, n=72 for biofilm metabolic activity, n=16 for cell viability and total biofilm quantification) with formed biofilm were divided into eight groups for manual brushing (20 seconds) with a dental brush and distilled water (NC: negative control), Trihydral (PC: positive control), placebo (Pl), BvK, Co, Ec, Ma or Ps. After brushing, the specimens were washed with PBS and immersed in Letheen Broth medium, and the suspension was sown in solid specific medium. The organoleptic characteristics were presented by descriptive analysis. The values of density, pH, consistency and viscosity were presented in a table. The data were analyzed with the Wald test in a generalized linear model, followed by the Kruskal-Wallis test, Dunn's test (mass change) and the Bonferroni test (UFC and XTT). The Wald test in Generalized Estimating Equations and the Bonferroni test were used to analyze cell viability. Results: All dentifrices showed stable organoleptic characteristics and adequate physicochemical properties. CN, Ec, Ps, Pl and PC showed low abrasiveness. There was a significant difference between the groups (p<0.001) for microbial load, metabolic activity and biofilm viability. Conclusions: It was concluded that the BvK, Ec and Ps dentifrices are useful for cleaning complete dentures, as they have antimicrobial activity against biofilm. The dentifrices containing Bowdichia virgilioides Kunth showed medium abrasiveness and should be used with caution.

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Abstract Studies evaluating the roughness, wettability and microbial adhesion of 3D-printed resins for complete denture bases and teeth are scarce. Objective This study evaluated the surface roughness, wettability and adhesion of multispecies biofilms (Candida albicans, Staphylococcus aureus and Streptococcus mutans) on 3D-printed resins for complete denture bases and teeth compared to conventional resins (heat-polymerized acrylic resin; artificial pre-fabricated teeth). Methodology Circular specimens (n=39; 6.0 mm Ø × 2.0 mm) of each group were subjected to roughness (n=30), wettability (n=30) and biofilm adhesion (n=9) tests. Three roughness measurements were taken by laser confocal microscopy and a mean value was calculated. Wettability was evaluated by the contact angle of sessile drop method, considering the mean of the three evaluations per specimen. In parallel, microorganism adhesion to resin surfaces was evaluated using a multispecies biofilm model. Microbial load was evaluated by determining the number of Colony Forming Units (CFU/mL) and by scanning electron microscopy (SEM). Data were subjected to the Wald test in a generalized linear model with multiple comparisons and Bonferroni adjustment, as well as two-way ANOVA (α=5%). Results The roughness of the conventional base resin (0.01±0.04) was lower than that of the conventional tooth (0.14±0.04) (p=0.023) and 3D-printed base (0.18±0.08) (p<0.001). For wettability, conventional resin (84.20±5.57) showed a higher contact angle than the 3D-printed resin (60.58±6.18) (p<0.001). Higher microbial loads of S. mutans (p=0.023) and S. aureus (p=0.010) were observed on the surface of the conventional resin (S. mutans: 5.48±1.55; S. aureus: 7.01±0.57) compared to the 3D-printed resin (S. mutans: 4.11±1.96; S. aureus: 6.42±0.78). The adhesion of C. albicans was not affected by surface characteristics. The conventional base resin showed less roughness than the conventional dental resin and the printed base resin. Conclusion The 3D-printed resins for base and tooth showed less hydrophobicity and less adhesion of S. mutans and S. aureus than conventional resins.

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OBJECTIVE: To assess the association between risk factors for developing denture stomatitis (DS) and oral health-related quality of life (OHRQoL) in complete denture wearers. METHODOLOGY: Participants of both sexes, wearing complete dentures, were classified using the modified Newton classification for the absence or the severity of DS and allocated to groups Normal or zero, IA, IB, II, and III. Lifestyle, oral and denture history, and medication use were assessed using specific questionnaires; clinical parameters such as anatomical characteristics of support were evaluated with the Kapur classification; salivary flow (SF) was calculated by the volume of unstimulated saliva per minute; and microbial load was determined by counting colony forming units (CFU) of target microorganisms present in the biofilm collected from dentures and palate. OHIP-EDENT assessed the OHRQoL. Kendall's tau_b and Spearman tests were applied with a significance level of 5%. RESULTS: 184 patients (143 female and 41 male) aged 65.5 ± 6.8 years were evaluated. Positive correlations were found for sex (women; p=0.013, r=0.16), individuals who started to consume alcoholic beverages as a young adult (18-27 years) (p=0.008, r=0.22), CFU of Candida spp. (p<0.001, r=0.27 denture; p<0.001, r=0.31 palate); Candida albicans (p=0.004, r=0.22 denture; p=0.003, r=0.25 palate), and Candida glabrata (p=0.004, r=0.22 denture; p=0.001, r=0.27 palate). Moreover, negative correlations with DS were found for CFU of Staphylococcus spp. (p=0.004, r=-0.20 palate) and enterobacteria (p=0.002, r=-0.24 palate), as well as a negative correlation between SF (p=0.009, r=-0.193) and DS. The CFU of Staphylococcus spp. and enterobacteria on the palate significantly correlated with OHRQoL. CONCLUSION: Being female, consuming alcoholic beverages as a young adult, CFU of Candida spp., Candida albicans, Candida glabrata, and salivary flow may be the most significant risk factors for DS. The microbial load of Staphylococcus spp. and enterobacteria seems to influence the quality of life for complete denture wearers.

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To assess the effect of hygiene protocols and time on the physical-mechanical properties and colony-forming units (CFU) of Candida albicans, Staphylococcus aureus, and Streptococcus mutans on 3D-printed denture resins (SmartPrint and Yller) with extrinsic pigmentation compared to conventional resin (CR). The protocols were evaluated: brushing (B), brushing and immersion in water (W), 0.25% sodium hypochlorite (SH), and 0.15% triclosan (T), simulating 0, 1, 3, and 5 years. The data were analyzed by ANOVA with repeated measurements, ANOVA (Three-way) and Tukey's post-test, generalized linear model with Bonferroni adjustment, and ANOVA (Two-way) and Tukey's post-test (α = 0.05). The protocols influenced color (p = 0.036) and Knoop hardness (p < 0.001). Surface roughness was influenced by protocols/resin (p < 0.001) and time/resin (p = 0.001), and flexural strength by time/protocols (p = 0.014). C. albicans showed interactions with all factors (p = 0.033). Staphylococcus aureus was affected by protocols (p < 0.001). Streptococcus mutans exhibited no count for SH and T (p < 0.001). Yller resin showed more color changes. The 3D-printed resins displayed lower microhardness, increased roughness, and decreased flexural strength compared to CR with all protocols in a simulated period of 5 years. The indication of printed resins should be restricted to less than 3 years.

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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.

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PURPOSE: To determine the effectiveness of palatal brushing in the treatment of denture-related erythematous stomatitis (DES) in complete denture wearers. METHODS: This two-parallel-arm RCT was conducted in three university clinics in Brazil, Canada, and Chile. Participants (n=77) were randomly allocated to receive (i) instructions for palatal brushing and standard oral/denture hygiene ("intervention"); or (ii) standard oral/denture hygiene instructions only ("control"). Data collection was carried out at the baseline and at 3 and 6 months after intervention. Outcomes included the magnitude of oral Candida carriage and the degree of inflammation of denture-bearing tissues. Groups were compared using generalized estimating equations and chi-square test (α=0.05). RESULTS: Palatal inflammation levels were reduced significantly in the "intervention" compared to "control" group at 6 months (intervention: 70%, control: 40%; chi-square, p=0.04). There was no between-group significant difference in the Candida count from denture and palatal biofilms; however, a subgroup analysis restricted to baseline Candida carriers showed further reduction with the intervention at 6 months. No adversity was observed by trialist or reported by participants. CONCLUSIONS: Including palatal brushing in oral instructions for denture wearers has positive impact on DES-related mucosal inflammation. Thus, our findings endorse the inclusion of palatal brushing in standard oral hygiene instructions to treat DES.

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Abstract Objective To assess the association between risk factors for developing denture stomatitis (DS) and oral health-related quality of life (OHRQoL) in complete denture wearers. Methodology Participants of both sexes, wearing complete dentures, were classified using the modified Newton classification for the absence or the severity of DS and allocated to groups Normal or zero, IA, IB, II, and III. Lifestyle, oral and denture history, and medication use were assessed using specific questionnaires; clinical parameters such as anatomical characteristics of support were evaluated with the Kapur classification; salivary flow (SF) was calculated by the volume of unstimulated saliva per minute; and microbial load was determined by counting colony forming units (CFU) of target microorganisms present in the biofilm collected from dentures and palate. OHIP-EDENT assessed the OHRQoL. Kendall's tau_b and Spearman tests were applied with a significance level of 5%. Results 184 patients (143 female and 41 male) aged 65.5 ± 6.8 years were evaluated. Positive correlations were found for sex (women; p=0.013, r=0.16), individuals who started to consume alcoholic beverages as a young adult (18-27 years) (p=0.008, r=0.22), CFU of Candida spp. (p<0.001, r=0.27 denture; p<0.001, r=0.31 palate); Candida albicans (p=0.004, r=0.22 denture; p=0.003, r=0.25 palate), and Candida glabrata (p=0.004, r=0.22 denture; p=0.001, r=0.27 palate). Moreover, negative correlations with DS were found for CFU of Staphylococcus spp. (p=0.004, r=-0.20 palate) and enterobacteria (p=0.002, r=-0.24 palate), as well as a negative correlation between SF (p=0.009, r=-0.193) and DS. The CFU of Staphylococcus spp. and enterobacteria on the palate significantly correlated with OHRQoL. Conclusion Being female, consuming alcoholic beverages as a young adult, CFU of Candida spp., Candida albicans, Candida glabrata, and salivary flow may be the most significant risk factors for DS. The microbial load of Staphylococcus spp. and enterobacteria seems to influence the quality of life for complete denture wearers.

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Denture-related stomatitis (DRS) is frequent oral inflammation in complete denture wearers. This study evaluated the effect of a hygiene protocol on DRS remission, local inflammatory factors, and hemodynamic responses. Thirty-three individuals were enrolled in the study. The outcomes were measured before and after 10 days of a hygiene protocol treatment consisting of brushing the palate with a soft brush and water and denture brushing with a denture-specific brush and mild soap, as well as immersion of the denture for 20 min in a 0.25% sodium hypochlorite solution. Data were analyzed by paired Wilcoxon for biofilm removal and CFU count of microorganisms. The paired T test was used to assess salivary MUC 1, cytokines, and arterial pressure (p < 0.05). A significant difference was found in the DRS degree (p < 0.001), biofilm (p < 0.001), microbial load of Candida spp. (p < 0.001), Gram-negative (p < 0.004), Staphylococcus spp. (p < 0.001), and S. mutans (p < 0.001) of the denture, and S. mutans (p < 0.001) of the palate after use of the protocol. The salivary flow (p = 0.2) and pH (p = 0.97) did not change; there was an increase of MUC 1 (p = 0.049) and a decrease in IL-6 (p = 0.038), IL-2 (p = 0.04), IL-10 (p = 0.041), and IFNγ (p = 0.04). There was also a decrease in systolic (p = 0.012) and mean arterial pressure (p = 0.02). The current hygiene protocol reduced the inflammation degree of DRS and promoted an improvement of local inflammatory factors and a reduction in the systolic arterial pressure of the patients.

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PURPOSE: This randomized controlled trial compared four denture hygiene protocols in terms of patient satisfaction, oral health-related quality of life (OHRQoL), and salivary parameters in complete denture wearers with denture stomatitis. MATERIAL AND METHODS: For this randomized, double-blind, controlled clinical trial, 108 participants were assigned to soak their dentures in one of the following solutions: (1) 0.25% sodium hypochlorite (positive control), (2) 0.15% Triclosan, (3) denture disinfecting tablets, or (4) denture disinfecting tablets plus palatine mucosa brushing solution. The outcomes of patient satisfaction, OHRQoL, and salivary parameters (salivary flow rate and pH) were measured at baseline and after 10 days. The Kruskal-Wallis and Dunn tests (between groups), and Wilcoxon test (between times) were used to compare the results. (α = 0.05). RESULTS: After the hygiene protocols, and when compared with baseline, the overall patient satisfaction, maxillary denture satisfaction, maxillary denture comfort, and maxillary denture retention were ameliorated. A significant improvement was noted in OHRQoL in 3 of 4 domains evaluated (orofacial pain and discomfort, masticatory discomfort and disability, and psychological disability and discomfort). The salivary flow rate (unstimulated and stimulated) and salivary pH were not significantly affected at the times evaluated. CONCLUSIONS: Complete denture wearers may feel more satisfied with their complete dentures when treated for denture stomatitis. The tested treatments lead to similar improvement in terms of patient satisfaction and OHRQoL.

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OBJECTIVE: This study evaluated the effect of different glucose concentration on biofilm formation of Candida albicans and Candida glabrata strains isolated from diabetic and non-diabetic individuals. METHODS: The study was divided into two stages: (I) selection and identification of 48 C. albicans and C. glabrata strains by polymerase chain reaction followed by restriction fragment length polymorphism analysis (PCR/RFLP); (II) evaluation of biofilm formation by means of viability rates (colony-forming units), biofilm dry matter (mg) and biofilm-covered areas (µm2). Statistical comparisons were performed through nonparametric analysis of longitudinal data in factorial experiments with pairwise comparisons using Friedman Conover's test (α = 0.05). RESULTS: All the Candida spp. had their identifications confirmed by PCR/RFLP. C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed higher viability rates than strains from non-diabetic individuals. No difference was observed on viability of C. glabrata biofilm. Regarding biofilm dry matter, C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed lower amount in weight than strains from non-diabetic individuals. In C. glabrata strains, this result was only observed in biofilms cultivated with no glucose supplementation. With regard to biofilm-covered areas, only glucose supplementation and non-diabetic condition showed a positive effect on C. albicans biofilm development, and no condition affected C. glabrata biofilm formation. CONCLUSION: The strain type (C. albicans and C. glabrata) isolated from diabetic and non-diabetic individuals influenced on biofilm formation, but glucose supplementation did not.

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Some studies have demonstrated a high prevalence of Candida species in patients with tuberculosis (TB). This is most likely due to long-term antimicrobial therapy. To date, no longitudinal studies addressed the effects of anti-TB treatment on the fungal burden and virulence of Candida spp. This study investigated the prevalence and virulence of Candida spp. in the oral cavity of 30 TB patients at different stages of treatment through a cohort study. These results were compared with those of 60 systemically healthy individuals in a cross-sectional study. Oral rinse samples from TB patients were collected before 45 and after 120 days of treatment. In the control group, the biological samples were collected only once. Candida spp. were identified by restriction fragment length polymorphism (RFLP) assays, and the following virulence factors were studied: phospholipase C and proteinase production, as well as Candida spp. biofilm and hyphae formation. The clinical diagnosis of TB and its treatment time were associated with the greater fungal burden (p < 0.0001), presence of non-albicans Candida (NAC) species (p = 0.0003), and increased virulence factors when compared with the Candida spp. isolated from systemically healthy individuals. The results showed that anti-TB treatment time was responsible for the increased fungal burden and isolation of NAC in TB patients (p = 0.0233). The increased prevalence, quantification, and virulence of Candida spp. isolated from the oral cavity of TB patients highlight the greater risk of oral lesions and cases of systemic dissemination in these patients.

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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.

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BACKGROUND: Understanding the behavior of Candida spp. when exposed to denture disinfectants is essential to optimize their effectiveness. Changes in the virulence factors may cause increased resistance of Candida spp. to disinfectant agents. OBJECTIVE: To evaluate the microbial load, cellular metabolism, hydrolytic enzyme production, hyphae formation, live cell and biofilm quantification of Candida albicans, Candida tropicalis and Candida glabrata after exposure to disinfectant solutions. METHODOLOGY: Simple biofilms were grown on heat-polymerized acrylic resin specimens, and divided into groups according to solutions/strains: distilled water (control); 0.25% sodium hypochlorite (NaOCl 0.25% ); 10% Ricinus communis (RC 10%); and 0.5% Chloramine T (CT 0.5%). The virulence factors were evaluated using the CFU count (microbial load), XTT method (cell metabolism), epifluorescence microscopy (biofilm removal and live or dead cells adhered), protease and phospholipase production and hyphae formation. Data were analyzed (α=0.05) by one-way ANOVA/ Tukey post hoc test, Kruskal-Wallis test and Wilcoxon test. RESULTS: NaOCl 0.25% was the most effective solution. CT 0.5% reduced the number of CFUs more than RC 10% and the control. RC 10% was effective only against C. glabrata. RC 10% and CT 0.5% decreased the cellular metabolism of C. albicans and C. glabrata. Enzyme production was not affected. Hyphal growth in the RC 10% and CT 0.5% groups was similar to that of the control. CT 0.5% was better than RC 10% against C. albicans and C. tropicalis when measuring the total amount of biofilm and number of living cells. For C. glabrata, CT 0.5% was equal to RC 10% in the maintenance of living cells; RC 10% was superior for biofilm removal. CONCLUSIONS: The CT 0.5% achieved better results than those of Ricinus communis at 10%, favoring the creation of specific products for dentures. Adjustments in the formulations of RC 10% are necessary due to efficacy against C. glabrata. The NaOCl 0.25% is the most effective and could be suitable for use as a positive control.

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Denture dentifrices must be effective and not deleterious to prosthetic devices. This study formulated and evaluated dentifrices based on oils of Copaifera officinalis, Eucalyptus citriodora, Melaleuca alternifolia, Pinus strobus, and Ricinus communis. Organoleptic characteristics (appearance, color, odor, taste), physicochemical properties (pH, density, consistency, rheological, abrasiveness, weight loss, and surface roughness) and antimicrobial (Hole-Plate Diffusion-HPD)/anti-biofilm (Colony Forming Units-CFU) action against Staphylococcus aureus, Streptococcus mutans, and Candida albicans were evaluated. Formulations were compared with water (negative control) and a commercial dentifrice (positive control). The data were analyzed by Kruskal-Wallis and Dunn tests (α = 0.05). The organoleptic and physicochemical properties were adequate. All dentifrices promoted weight losses, with high values for C. officinalis and R. communis, and an increase in surface roughness, without differing from each other. For antimicrobial action, C. officinalis and E. citriodora dentifrices were similar to positive control showing effectiveness against S. mutans and C. albicans and no dentifrice was effective against S. aureus; regarding the anti-biofilm action, the dentifrices were not effective, showing higher CFU counts than positive control for all microorganisms. The dentifrices presented satisfactory properties; and, although they showed antimicrobial action when evaluated by HPD, they showed no effective anti-biofilm action on multispecies biofilm.

RESUMEN

The use of bacteriophages for the treatment of bacterial infections has been extensively studied. Nonetheless, the stress response regarding bacteriophage infection and the expression of virulence factors of Pseudomonas aeruginosa after phage infection is poorly discussed. In this study, we evaluated biofilm formation capacity and expression of virulence factors of P. aeruginosa after bacteriophage infection. Biofilm growth rates, biofilm morphology, pyocyanin production and elastase activity were evaluated after 2, 8, 24 and 48 h of co-cultivation with bacteriophages that was recently characterized and showed to be infective towards clinical isolates. In parallel, quantitative real-time polymerase chain reactions were carried out to verify the expression of virulence-related genes. Bacteriophages promoted substantial changes in P. aeruginosa biofilm growth at early co-culture time. In addition, at 8 h, we observed that some cultures developed filaments. Although bacteriophages did not alter both pyocyanin and protease activity, changes on the expression level of genes related to virulence factors were detected. Usually, lasI, pslA, lasB and phzH genes were upregulated after 2 and 48 h of co-culture. These results highlight the need for extensive investigation of pathways and molecules involved in phage infection, since the transcriptional changes would suggest a response activation by P. aeruginosa.

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