Antimicrobial effect and the mechanical and surface properties of a self-disinfecting and a chlorhexidine-incorporated Type IV dental stone.

STATEMENT OF PROBLEM: Stone casts are subject to contamination, but whether disinfectants incorporated into the stone are effective is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the antimicrobial activity and the mechanical and surface properties of self-disinfecting gypsum (SDG) and gypsum mixed with 2% chlorhexidine (GCHX). MATERIAL AND METHODS: Antimicrobial action was evaluated using the diffusion-disk technique on Streptococcus aureus and Candida albicans 1 hour and 24 hours after pouring the gypsum. The groups were SDG, GCHX, a positive control (PC) of gypsum mixed with distilled water, and a negative control (NC) of filter paper disk soaked with 2% chlorhexidine; n=8. Inhibition halos were measured using the ImageJ software program and statistically analyzed using the repeated measures mixed ANOVA with time×group interaction. Compressive strength (CS) in MPa and surface roughness (SR) in µm (parameters: Ra - roughness average; and Sa - 3-dimensional (3D) arithmetic mean of the surface profile) tests were performed to characterize the specimens (evaluated groups: SDG, GCHX, and PC; n=10). CS data were analyzed by a 2-way ANOVA with time×group interaction, and SR data by a 1-way ANOVA (α=.05). RESULTS: For S aureus, there were differences between GCHX and SDG at 1 hour and 24 hours (P<.05), but no significant differences were found for C albicans (P>.05). GCHX was better than PC, except for C albicans, and showed a reduction in CS when compared with PC and SDG (P<.05) at all time intervals. The SR of GCHX increased (Ra:1.76, Sa:2.08) when compared with PC (Ra:0.89, Sa:1.12) and SDG (Ra:1.03, Sa:1.35) (Ra: P<.004 and Sa: P<.001). CONCLUSIONS: The antimicrobial activity of GCHX against S aureus was better than that of SDG, but neither had an effect against C albicans. As for CS and SR, GCHX presented a decrease in properties when compared with PC and SDG but was within the American Dental Association #25 specification values.

Effects of hybrid inorganic-organic nanofibers on the properties of enamel resin infiltrants - An in vitro study.

This in vitro study aimed to evaluate the overall mechanical properties of resin infiltrants doped with bioactive nanofibers and their ability in inhibiting enamel demineralization or achieving remineralization of the adjacent enamel to white spots. A commercial resin infiltrant (ICON, DMG) was doped with hybrid inorganic-organic nanofibers and analyzed for degree of conversion (DC, n = 3) and surface hardness (SH, n = 6). Subsequently, enamel specimens (6 × 4 × 2 mm3) were prepared and submitted to a demineralizing/remineralizing process to produce a subsurface caries-like lesion. The specimens were treated with one of the following materials: ICON infiltrant, DMG (control); ICON + nanofibers of poly-lactic acid (PLA)-filled with silica (PLA-SiO2); ICON + nanofibers of (PLA)-filled with calcium incorporated into a silica network (SiO2-CaP). Then, the specimens were subjected to a pH-cycling demineralizing/remineralizing model for 7 days at 37 °C. The %ΔSH change (after treatment), %SH loss and %SH recovery (after pH-cycling regimen) were calculated after SH evaluation (n = 9/group). The Ca/P weight ratio before and after pH-cycling regimen was evaluated through SEM/EDX. The results of DC were analyzed through the T-test (p < 0.05). ANOVA followed by Tukey's test (p < 0.05) was performed for hardness and EDX. A significant SH increase was observed in the ICON/SiO2CaP group (p < 0.05). The ICON/PLA-SiO2 presented higher DC values than the control group (p = 0.043). All groups presented significant difference in %ΔSH (p < 0.05), although the specimens treated with ICON/SiO2CaP presented greater values. Regarding the %SHL and %SHR, the ICON/SiO2CaP and ICON/PLA-SiO2 were significantly different compared to the control group (p < 0.001). However, no difference was observed between the ICON/SiO2CaP and ICON/PLA-SiO2. The Ca/P ratio showed that the ICON/SiO2CaP and ICON/PLA-SiO2 after the pH-cycling regimen differed from sound enamel and modified infiltrants before pH-cycling. In conclusion, tailored hybrid nanofibers may be incorporated into enamel resin infiltrants without compromise the mechanical properties of such experimental materials. These latter can inhibit the demineralization of enamel and increase its hardness during pH-clycling challange.

Efficacy of essential oil of cinnamon for the treatment of oral candidiasis: A randomized trial.

AIM: It was analyzed the efficacy of mouthwash and spray containing essential oil (EO) of Cinnamomum zeylanicum Blume for the treatment of oral candidiasis. METHODS AND RESULTS: A randomized, controlled, and blinded clinical trial was conducted with 36 individuals (probabilistic sample) with oral candidiasis who were divided into two treatment groups: C. zeylanicum (0.5 mg/mL), n = 18; nystatin (100,000IU/mL), n = 18. The efficacy of the products was evaluated by two parameters: (a) clinical evolution recorded by calibrated examiners (Kappa = 0.822) according to Newton's classification and (b) reduction of colony-forming units/mL. Mycological and clinical parameters were analyzed before and at 15 days after treatment. Clinical examination of the mucosa showed that C. zeylanicum (p < 0.0339) and nystatin (p < .0139) had efficacy, resulting in a reduction of signs and symptoms (Mann-Whitney test). Mycological analysis showed that C. zeylanicum caused a reduction of 61% and 33% of Candida spp., isolates oral mucosa and dentures, respectively. Candida tropicalis strains were eliminated after C. zeylanicum, in both sites. The participants reported a pleasant taste and few product-related complaints. CONCLUSION: C. zeylanicum EO and nystatin exhibited clinical efficacy, according to the Newton classification, and reducing in Candida spp. The clinical trial has been registered (Registration number: NBR-33s6 × 5, ensaiosclinicos.gov.br).

Chitosan/PCL nanoparticles can improve anti-neoplastic activity of 5-fluorouracil in head and neck cancer through autophagy activation.

Head and neck squamous cell carcinoma (HNSCC), a prevalent cancer worldwide, has a high incidence of loco-regional dissemination, frequent recurrence, and lower 5-year survival rates. Current gold standard treatments for advanced HNSCC rely primarily on radiotherapy and chemotherapy but with limited efficacy and significant side effects. In this study, we characterized a novel 5-fluorouracil (5-FU) carrier composed of chitosan solution (CS) and polycaprolactone (PCL) microparticles (MPs) in HNSCC preclinical models. The designed MPs were evaluated for their size, morphology, drug entrapment efficiency (EE%) and in vitro drug release profile. The anti-cancer activity of 5-FU-loaded particles was assessed in HNSCC human cell lines (CAL27 and HSC3) and in a preclinical mouse model (AT84) utilizing cell proliferation and survival, cell motility, and autophagy endpoints. The results demonstrated a 38.57 % in 5-FU entrapment efficiency associated with reduced 5-FU in vitro release up to 96 h post-exposure. Furthermore, CS-decorated PCL MPs were able to promote a significant inhibition of cancer cell proliferation based on the metabolic and colony formation assays, in comparison to controls. In contrast, CS-decorated PCL MPs did not influence the pharmacological efficacy of 5-FU to inhibit in vitro cancer cell migration. Last, cell protein analysis revealed a significant increase of autophagy and cell death evaluated by LC3-II expression and PARP1 cleavage, respectively. In summary, these results support the potential utility of CS-decorated PCL MPs as an effective 5-FU-delivery carrier to improve HNSCC therapeutic management.

Current Applications of Biopolymer-based Scaffolds and Nanofibers as Drug Delivery Systems.

BACKGROUND: The high surface-to-volume ratio of polymeric nanofibers makes them an effective vehicle for the release of bioactive molecules and compounds such as growth factors, drugs, herbal extracts and gene sequences. Synthetic polymers are commonly used as sensors, reinforcements and energy storage, whereas natural polymers are more prone to mimicking an extracellular matrix. Natural polymers are a renewable resource and classified as an environmentally friendly material, which might be used in different techniques to produce nanofibers for biomedical applications such as tissue engineering, implantable medical devices, antimicrobial barriers and wound dressings, among others. This review sheds some light on the advantages of natural over synthetic polymeric materials for nanofiber production. Also, the most important techniques employed to produce natural nanofibers are presented. Moreover, some pieces of evidence regarding toxicology and cell-interactions using natural nanofibers are discussed. Clearly, the potential extrapolation of such laboratory results into human health application should be addressed cautiously.

Cytokine Regulation from Human Peripheral Blood Leukocytes Cultured In Vitro with Silver Doped Bioactive Glasses Microparticles.

Bioactive glasses (BG) applications include tissue engineering for bone regeneration, coating for implants, and scaffolds for wound healing. BG can be conjugated to ions like silver, which might add some antimicrobial properties to this biomaterial. The immunomodulatory activity of ion-doped bioactive glasses particles was not investigated before. The aim of this work was to evaluate the cytotoxic and immunomodulatory effect of BG and silver-doped bioactive glass (BGAg) in human peripheral blood cells. BG and BGAg samples belonging to the system 58SiO2 •(36-x)CaO·6P2O5 ·xAg2O, where x = 0 and 1 mol%, respectively, were synthesized via sol-gel method and characterized. Cytotoxicity, modulation of cytokine production (TNF-α, IL-1ß, IL-6, IL-4, and IL-10), and oxidative stress response were investigated in human polymorphonuclear cells (PMNs) and peripheral blood mononuclear cells (PBMCs) cultures. Cell viability in the presence of BG or BGAg was concentration-dependent. In addition, BGAg presented higher PBMCs toxicity (LC50 = 0.005%) when compared to BG (LC50 = 0.106%). Interestingly, interleukin4 was produced by PBMCs in response to BG and BGAg in absence of phytohemagglutinin (PHA) and did not modulate PHA-induced cytokine levels. Subtoxic concentrations (0.031% for BG and 0.0008% for BGAg) did not change other cytokines in PBMCs nor reactive oxygen species (ROS) production by PMN. However, BG and BGAg particles decreased zymosan-induced ROS levels in PMN. Although ion incorporation increased BG cytotoxicity, the bioactive glass particles demonstrated a in vitro anti-inflammatory potencial. Future studies are needed to clarify the scavenger potential of the BG/BGAg particles/scaffolds as well as elucidate the effect of the anti-inflammatory potential in modulating tissue growth in vivo.

Anticandida and antibiofilm activities of extract from Schinopsis brasiliensis Engl. against Candida spp

Abstract The pathogenic nature of infections caused by Candida spp. underscores the necessity for novel therapeutic agents. Extracts of Schinopsis brasilienses Engl are / a promising source of agents with antifungal effects. This study aimed to assess the antifungal potential of the leaf extract of S. brasilienses. The antifungal activity was evaluated by determining the minimum inhibitory concentrations and fungicide concentrations (MIC and MFC). The antibiofilm potential was assessed by counting colony-forming units/mL. The study examined the inhibition kinetics of fungal growth and potential synergism between gallic acid or the extract and nystatin using the Checkerboard method. Cytotoxicity was evaluated through the MTT assay. The extract exhibited antifungal effect against all tested strains, with MIC and MFC ranging from 31.25-250 μg/mL. Gallic acid, the main isolated compound, displayed a MIC of 2000 μg/mL. The extract of S. brasilienses at 31.25 μg/mL inhibited the formation of biofilm by C. albicans and significantly reduced the mass of mature biofilm after 24 and 48 h (p < 0. 05). At a concentration of 125 μg/mL, the extract demonstrated significant inhibition of fungal growth after 6 hours. The combination of gallic acid or extract with nystatin did not exhibit synergistic or antagonistic effect. Furthermore, the extract did not induce cytotoxicity to a human cell line. The extract of S. brasiliensis demonstrates antifungal activity against Candida, generally exhibiting fungicidal action and capacity to inhibit biofilm formation as well as reduce mature biofilms. Additionally, the extract showed low cytotoxicity to human cells.

Effect of chitosan nanoparticles on the inhibition of Candida spp. biofilm on denture base surface.

OBJECTIVES: Chitosan nanoparticles (ChNPs) have antifungal effects, however there is a lack of information about the effects of ChNPs against Candida biofilm on denture base surface. This study investigated the ChNPs effect against C. albicans biofilm adhesion and formation, and against Candida spp. biofilm on heat-cured acrylic resin. DESIGN: The ChNPs were synthetized (3800 µg/mL) and characterized by infra-red spectrophotometry and transmission electron microscopy. The minimum inhibitory/fungicidal concentrations (MIC/MFC) against Candida spp. were determined. The time-kill assay and changes on C. albicans micromorphology were evaluated. The % inhibition of ChNPs on C. albicans biofilm formation and reduction were investigated using 1 min and 8 h exposure. Candida biofilm was developed on resin surfaces and ChNPs were applied every 8 h for 5 days. After, fungal cells were counted (CFU/mL) and the surface roughness (Ra) and vickers microhardness (HV) of resin were analysed. For all experiments, sodium hypochlorite (NaOCl) was used as control. Data were analyzed by ANOVA, Tukey and paired t-tests (α = 0.05). RESULTS: The MIC80% of ChNPs was 30.1 µg/mL. ChNPs at 4 MIC showed complete inhibition in the time-kill assays. Blastoconidia cells were predominant after ChNPs application. The % inhibition ChNPs on C. albicans was proportional to its concentration, regardless of the exposure time. ChNPs decreased the CFU/mL of Candida spp. and showed lower alteration of HV and Ra values of resin surface compared to NaOCl. CONCLUSIONS: The ChNPs inhibited C. albicans biofilm, reduced Candida biofilm on resin and caused small changes in roughness and hardness of acrylic resin surface.

SARS-CoV-2 and Saliva as a Diagnostic Tool: A Real Possibility

Abstract Covid-19 is a respiratory disease caused by the SARS-CoV-2 virus. The high rate of contagion and the spread of the virus in the population make the early detection of the pathogen the means for the adequate targeting of infection control measures. WHO directs sample collection on upper respiratory specimens, including nasopharyngeal and oropharyngeal swab or wash in ambulatory patients, as well as lower respiratory specimens: sputum and/or endotracheal aspirate or bronchoalveolar lavage, in addition to citing blood and feces. Among the various sample collection methods, saliva has been investigated and reported as a potential source for diagnosis. Thus, we propose to evaluate the current scenario, based on recent publications on the perspective of detecting SARS-CoV-2 in saliva as a diagnostic method for Covid-19. The detection of SARS-CoV-2 through saliva seems to be very promising, although obstacles such as the technique and the location of the collection and the sample size of the research carried out so far may present a limitation for its use. The current scenario presents saliva as a reliable method for the detection of SARS-CoV-2, due to the ease of obtaining the samples, the possibility of self-collection, low cost because there is no need to use specific equipment, in addition to reducing the risk of transmission for health professionals.

Anti-Biofilm and Hemolytic Effects of Cymbopogon citratus (Dc) Stapf Essential Oil

Abstract Objective: To perform chemical analysis and to evaluate the anti-biofilm and hemolytic effect of the essential oil of Cymbopogon citratus. Material and Methods: Gaseous chromatography coupled to mass spectrometer was performed for chemical characterization of the essential oil. To verify the antimicrobial action, the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) were determined. From MIC, MBC and MFC data, concentrations were established to verify the anti-biofilm effect and for the hemolysis test on human erythrocytes. A multispecies biofilm was developed in vitro and mouthwash applications were simulated to determine the inhibition of biofilm formation or its removal. Results were analyzed through ANOVA statistical test, complemented by the Tukey test, considering a significance level of 5% Results: The major component of the essential oil is citral. MIC verified for Streptococcus mutans was 1mg / mL, while for Candida albicans, it was 125 μg/mL, presenting microbicidal effect for both microorganisms tested. The essential oil was able to inhibit biofilm formation (p<0.001), presenting non-toxic hemolysis percentage in concentration below 500 μg/mL Conclusion: The essential oil of Cymbopogon citratus is antimicrobial, antibiofilm and non-toxic to human erythrocytes, representing a natural product with potential for use in Dentistry.