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

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.

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.

Novel Therapeutic Options for Chagas Disease Based on Bioactive Compounds from Algae, Bacteria and Fungi Species.

Chagas Disease, also known as American trypanosomiasis, is a Neglected Tropical Disease that affects around seven million people, especially in Latin America. Noteworthy, there has been an increase in the numbers of case reports in non-endemic areas, such as North America, Europe, Japan, and Australia. The disease is a vector-borne disease caused by the pathogen Trypanosoma cruzi being transmitted by infected bugs. It is known that about forty percent of infected patients develop cardiac, digestive, or neurological alterations. There are only two drugs currently used for treatment, benznidazole and nifurtimox. However, both therapeutic regimens present several limitations, such as toxicity, mutagenicity and low efficiency during the chronic phase. Some reports in the literature point to the occurrence of parasite resistance. To overcome these limitations, the bioprospection of novel molecules as alternatives is one of the major goals to improve therapeutic success in this chronic disease. Bioprospecting active metabolites from natural resources might bring new hopes for disease control and parasite elimination. Here we summarize the most recent advances to identify and test Algae, Bacteria and Fungi-derived bioactive compounds with trypanocidal activity using experimental models, in vitro testing and in silico approaches.

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.

Nanoparticle-Mediated Drug Delivery: Blood-Brain Barrier as the Main Obstacle to Treating Infectious Diseases in CNS.

BACKGROUND: Parasitic infections affecting the central nervous system (CNS) present high morbidity and mortality rates and affect millions of people worldwide. The most important parasites affecting the CNS are protozoans (Plasmodium sp., Toxoplasma gondii, Trypanosoma brucei), cestodes (Taenia solium) and free-living amoebae (Acantamoeba spp., Balamuthia mandrillaris and Naegleria fowleri). Current therapeutic regimens include the use of traditional chemicals or natural compounds that have very limited access to the CNS, despite their elevated toxicity to the host. Improvements are needed in drug administration and formulations to treat these infections and to allow the drug to cross the blood-brain barrier (BBB). METHODS: This work aims to elucidate the recent advancements in the use of nanoparticles as nanoscaled drug delivery systems (NDDS) for treating and controlling the parasitic infections that affect the CNS, addressing not only the nature and composition of the polymer chosen, but also the mechanisms by which these nanoparticles may cross the BBB and reach the infected tissue. RESULTS: There is a strong evidence in the literature demonstrating the potential usefulness of polymeric nanoparticles as functional carriers of drugs to the CNS. Some of them demonstrated the mechanisms by which drugloaded nanoparticles access the CNS and control the infection by using in vivo models, while others only describe the pharmacological ability of these particles to be utilized in in vitro environments. CONCLUSION: The scarcity of the studies trying to elucidate the compatibility as well as the exact mechanisms by which NDDS might be entering the CNS infected by parasites reveals new possibilities for further exploratory projects. There is an urgent need for new investments and motivations for applying nanotechnology to control parasitic infectious diseases worldwide.

Synthesis and characterization of TPP/chitosan nanoparticles: Colloidal mechanism of reaction and antifungal effect on C. albicans biofilm formation.

In the present study chitosan (Chit) nanoparticles were synthetized by the ionic gelation process, using tripolyphosphate (TPP) as crosslinking agent. The TPP/Chit nanoparticle formation was evaluated by titrations, measuring electrical conductivity (k), zeta potential (ZP), hydrodynamic diameter (Dh), viscosity (η) and heat by isothermal calorimetry (ITC). The antifungal effects were evaluated by C. albicans time-kill assays, inhibition of C. albicans initial adhesion and biofilm formation in comparison with nystatin and chitosan. Conductometric titration exhibited a typical precipitation profile, with an inflection at molar ratio of [TPP]/[Chitmon] ≈ 0.3, suggesting a 1:3.3 stoichiometry. The highest Dh, ZP and η values were shown at the beginning of titrations, due to the intramolecular repulsion between Chit-Chit. With addition of TPP, the values showed gradual reduction, with an intermediary transition at [TPP]/[Chitmon] ≈ 0.16, which was attributed to the partial breakdown of interchain crosslinking and formation of discrete charged aggregates. After this point, reaction should occur by neutralization of these assemblies, causing new reduction in values of Dh, ZP and η until [TPP]/[Chitmon] ≈ 0.3, when they reached their lowest values. ITC experiment also showed the occurrence of two bindings (K1 = 3.6 × 103 and K2 = 7.7 × 104), which were entropy driven. Biological results showed lower C. albicans viability for TPP/Chit over 24 h compared with chitosan and nystatin at MIC and 2 MIC. Moreover, TPP/Chit showed 25-50% inhibition of C. albicans adhesion and biofilm formation. The results showed that TPP/Chit nanoparticles reduced the initial adhesion and biofilm formation of C. albicans and demonstrated potential for use in a formulation for the treatment of oral candidiasis.

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.

Effects of erosive challenge on the morphology and surface properties of luting cements / Efeito do desafio erosivo na morfologia e propriedades de superfície de agentes cimentantes

Introduction: Few studies investigated the surface properties of luting cements after erosive challenge. Objective: To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method: Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result: After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion: Erosive challenge with a cola drink affected the surface properties of all luting cements.

Introdução: Poucos estudos investigaram as propriedades de superfície de cimentos após desafio erosivo. Objetivo: Avaliar a rugosidade da superfície (Ra), dureza Vickers (VHN) e morfologia de superfície de 4 cimentos após desafio erosivo. Material e método: Vinte amostras de cada cimento foram preparadas (4×2mm) e divididas em grupo experimental (desafio erosivo) e controle (saliva artificial) (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) e Fosfato de Zinco (ZnP). O desafio erosivo foi realizado com quatro ciclos erosivos diárias (90s) em bebida à base de cola e 2h em saliva artificial durante 7 dias. As leituras de Ra e VHN foram realizadas antes e após erosão. A porcentagem de perda de dureza (%VHN) foi obtida depois da erosão. A morfologia de superfície foi analisada por microscopia eletrônica de varredura (MEV). Foram utilizados testes de ANOVA, Tukey e T-Student (α=0,05). Resultado: Após a erosão, foi observado aumento dos valores de Ra em todos os cimentos testados, e os grupos U200 e ZNP tiveram a maior %VHN. Após imersão em saliva, apenas os grupos U200 e ZnP tiveram aumento significativo nos valores de Ra e não houve diferenças significativas entre os grupos quanto à %VHN. A análise em MEV mostrou que os grupos Ketac e ZNP apresentaram superfícies rugosas e porosas, e o grupo U200 apresentou maior degradação da matriz comparado ao grupo ARC. Conclusão: O desafio erosivo com bebida a base de cola afetou as propriedades de superfície de todos os cimentos.

In vitro effects of erosive challenge on the surface properties of sealants

To assess in vitro the surface roughness (Ra), Vickers hardness (VHN) and surface morphology of resin and glass ionomer materials used for sealants after dynamic erosive challenge. Methods: Twenty specimens of each material were prepared and divided into experimental (erosive challenge) and control groups (n=10): Protect Riva (SDI), Opallis Flow (3M ESPE), Fluroshield (Dentsply), Filtek Z350 XT Flow (3M ESPE). The erosive challenge was performed 4 times per day (90 s) in cola drink and for 2 h in artificial saliva for 7 days. The control specimens were maintained in artificial saliva. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was evaluated by scanning electron microscopy (SEM). The data were analyzed by ANOVA, Tukey and paired t tests (á=0.05). Results: After erosion and saliva immersion, there was an increase in Ra values for all groups and Riva group showed the highest Ra values. After erosive challenge, Riva and Filtek groups showed significant decrease in VHN values, but Filtek group showed the greatest %VHN. For all groups there was inorganic particle protrusion and matrix degradation after erosion visualized by SEM images. Conclusions: Erosive challenge affected the surface properties of all materials used as sealants, particularly in the Riva and Filtek groups...

Physical properties and antibacterial activity of herbal tinctures of calendula (Calendula officinalis L) and cashew tree (Anacardium occidentale L)

Objective: To evaluate in vitro the pH, Brix and antibacterial activity of herbal tinctures of calendula (Calendula officinalis L.) and cashew tree (Anacardium occidentale L.) against the following bacterial strains: Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 10557), Streptococcus salivarius (ATCC 9758), Enterococcus faecalis (ATCC 29212) and Eikenella corrodens (ATCC 23834). Material and Method: The strains were reactivated in agar Brain Heart Infusion (BHI) and seeded in blood agar with BHI. Susceptibility tests were performed and the strains were incubated in microaerophilia (37 °C) for 48 h. Chlorhexidine at 0.12% was used as a positive control and distilled water as a negative control. Dilution of the tinctures was carried out from 1:1 (pure form) to 1:64 in alcohol 70%, which is found in their composition, in order to evaluate a possible influence of alcohol on the antibacterial activity of the tinctures. O Bx readings were made by refractometry using an Abbe refractometer and the pH was measured using a digital pH meter. Results: The calendula tincture had pH=5.43 and 18 °Brix and cashew tree tincture had pH=7.2 and 17 °Brix. The cashew tree tincture did not presentantibacterial activity against S. oralis, but it inhibited the growth of all other bacteria up to the 1:64 dilution. The calendula tincture presented antibacterial activity against S. oralis up to 1:16 dilution (6.5 mm halo diameter); against S. mutans and S. salivarius up to 1:32 dilution (7 and 7.5 mm halo diameter, respectively); and against E. faecalis and E. corrodens up to 1:64 dilution. Alcohol 70% did not show any antibacterial activity against the bacterial strains. Conclusion: The tinctures of calendula and cashew tree have soluble solids, have different pH values and present a significant antibacterial activity against several bacterial strains, except for the cashew tree tincture against S. oralis, which was ineffective...

Avaliação da atividade antibacteriana das tinturas de Hamamelis virginiana L. e Stryphnodendron rotundifolium Mart. frente a bactérias bucais / Evaluation of the antibacterial activity of Hamamelis virginiana L. andStryphnodendron rotundifolium Mart. tinctures against oral bacteria

Objetivo: Avaliar, in vitro, a atividade antibacteriana dastinturas de Hamamélis (Hamamelis virginiana L.) eBarbatimão (Stryphnodendron rotundifolium Mart.) sob as bactérias Streptococcus mutans (ATCC 25175),Streptococcus oralis (ATCC 10557) e Streptococcussalivarius (ATCC 9758). Materiais e Metodos: Utilizou-se aclorexidina 0,12% como controle positivo. Água destilada e álcool 70% foram escolhidos como controles negativos.Efetivou-se a diluição das tinturas desde 1:1 (forma pura)até 1:64 (D6) em álcool 70%, o qual está presente na fórmula das tinturas fitoterápicas. O meio de cultura bacteriana utilizado foi o Brain Heart Infusion (BHI), havendo as emeadura em placas de petri com auxílio de swabs.Realizou-se o teste de suscetibilidade e, em seguida, foram incubadas a 37°C, em microaerofilia, por 48 horas. O estudo foi realizado em duplicata e os halos foram mensurados como auxílio de um paquímetro manual. Resultados: O controle positivo apresentou halos de inibição de 16, 15, e 16 mmpara S. mutans, S. oralis e S. salivarius, respectivamente.Nenhuma das tinturas avaliadas, em quaisquer formas,diluídas ou puras, obteve halos de inibição para estas bactérias bucais. A água destilada e o álcool também não promoveram atividade. Conclusão: As tinturas da Hamamélise Barbatimão não apresentam atividade antibacteriana sobreS. mutans, S. oralis e S. salivarius.

Objective: To evaluate the in vitro the antibacterial activity ofthe Hamamelis (Hamamelis virginiana L.) and Barbatimão(Stryphnodendron rotundifolium Mart.) tinctures againstStreptococcus mutans (ATCC 25175), Streptococcus oralis(ATCC 10557) and Streptococcus salivarius (ATCC 9758).Material and Methods: Chlorhexidine (0.12%) was used aspositive control. Distilled water and 70% alcohol were chosenas negative controls. The dilution of the tinctures was carriedout from 1:1 (pure form) to 1:64 (D6) in 70% alcohol, which isfound in the tinctures formula. The culture medium Brain Heart Infusion (BHI) was used, and microorganisms were inoculatedon petri plates using swabs. Plates were incubated at 37 ºC,in microaerophilia, for 48 hours. Tests were performed induplicate and halos were measured using a manual caliper.Results: The positive control showed inhibition halos of 16,15, and 16 mm on S. mutans, S. oralis and S. salivarius,respectively. None of the tinctures evaluated, in any form(diluted or pure), were found to show inhibition halos onthese oral bacteria. Distilled water and 70% alcohol did not exhibit activity. Conclusion: The tinctures of Hamamelis and Barbatimão did not demonstrated antibacterial activity on S.mutans, S. oralis and S. salivarius.

In vitro antibacterial and non-stick activity of extracts from leaves of Psidium guineense Sw. and Syzygium cumini (L.) Skeels on oralmicroorganisms / Atividade antibacteriana e antiaderente in vitro dos extratos das folhas de Psidium guineense Sw. e Syzygium cumini (L.) Skeels sobre microrganismos orais

Objective: This study determined the Minimum Inhibitory Concentration and the Minimum Inhibitory Concentration of Adherence of hydroalcoholic extracts of the leaves of strawberry guava (Psidium guineense Sw.) and of the jambolan (Syzygium cumini (L.) Skeels) against Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 10557), Streptococcus parasanguis (ATCC 903), Streptococcus salivarius (ATCC 7073), Streptococcus sp (ATCC 15300), and Lactobacillus casei (ATCC 9595). Methods: Strains were seeded on blood agar plates to determine the Minimum Inhibitory Concentration by the agar-diffusion technique. The inclined tubes technique was used for Minimum Inhibitory Concentration of Adherence evaluation in the presence of 5% of sucrose, in Mueller-Hinton broth. The same procedures were accomplished with the 0.12% chlorhexidine digluconate (positive control). Assays were performed in duplicate. The plates and the tubes were maintained in microaerophillia at 37ºC for 24 hours. Results: The Minimum Inhibitory Concentration obtained for strawberry guava extract ranged from 275 to 1100 mg.ml-1. Jambolan values were 242.5 to 485 mg.mL-1; and 0.12% chlorhexidine digluconate were 75x10-3 to 9x10-3 mg.ml-1. The Minimum Inhibitory Concentration of Adherence reported the following values : strawberry guava (1.81 to 28.94 mg.ml-1); jambolan (1.60 to 12.76 mg.ml-1) and 0.12% chlorhexidine didigluconate (4.93 x10-4 to 19.70 x10-4 mg.ml-1). Conclusion: It was concluded that the hydroalcoholic extracts from the leaves of P. guineense Sw. and S. cumini (L.) Skeels presented antimicrobial and nonstick effect on the tested lineages; further studies are needed to confirm these extracts to be natural antibacterial agents for use in controlling dental caries.

Objetivo: Determinar a Concentração Inibitória Mínima e a Concentração Inibitória Mínima de Aderência dos extratos hidroalcoólicos das folhas do araçá (Psidium guineense Sw.) e do jambolão (Syzygium cumini (L.) Skeels) frente à Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 10557), Streptococcus parasanguis (ATCC 903), Streptococcus salivarius (ATCC 7073), Streptococcus sp (ATCC 15300) e Lactobacillus casei (ATCC 9595). Métodos: As cepas foram semeadas em placas de ágar sangue para determinação da CIM pela técnica de ágar-difusão. Utilizou-se a técnica dos tubos inclinados para avaliação da Concentração Inibitória Mínima de Aderência ao vidro, na presença de 5% de sacarose, em caldo Mueller-Hinton. Os mesmos procedimentos foram realizados com o digluconato de clorexidina à 0,12% (controle positivo). Os ensaios foram realizados em duplicata. As placas e os tubos foram mantidos em microaerofilia a 37ºC por 24 horas. Os dados foram analisados descritivamente. Resultados: As Concentrações Inibitórias Mínimas obtidas para o extrato do araçá variaram de 275 a 1100 mg.ml-1. Para o extrato do jambolão apresentaram valores de 242,5 a 485 mg.ml-1. E quanto ao digluconato de clorexidina à 0,12% foram de 9x10-3 a 75x10-3 mg.ml-1. Quanto às Concentrações Inibitórias Mínimas de Aderência, registrou-se os seguintes valores: araçá (1,81 a 28,94 mg.ml-1); jambolão (1,60 a 12,76 mg.ml-1) e digluconato de clorexidina à 0,12% (4,93x10-4 a 19,70x10-4 mg.ml-1). Conclusão: Conclui-se que os extratos hidroalcoólicos das folhas de P. guineense Sw. e S. cumini (L.) Skeels apresentaram efeito antimicrobiano e antiaderente sobre as linhagens testadas, sendo necessários estudos complementares que confirmem ser estes extratos alternativas de antibacterianos naturais no controle da cárie dentária.

Avaliação microestrutural do esmalte bovino exposto a bebidas lácteas fermentadas e propriedades físico químicas / Microstructural evaluation of bovine enamel exposed to fermented dairy beverages and analysis of their physical-chemical properties

Objetivo: Analisar o padrão de desmineralização do esmalte bovino submetido à ação de bebidas lácteas fermentadas frente a variações de tempo e avaliar as propriedades físico-químicas destes componentes da dieta líquida. Método: Analisaram-se seis marcas de bebidas lácteas, utilizando-se refrigerante a base de cola e água destilada como controle positivo (CP) e negativo (CN), respectivamente. Avaliou-se o pH por meio de pHmêtro digital enquanto a concentração de sólidos solúveis totais (°Brix) foi mensurada por um refratômetro específico de campo. Por meio de um viscosímetro capilar aferiu-se a viscosidade cinemática. Analisou-se a ação das bebidas sobre o esmalte em Microscopia Eletrônica de Varredura (MEV) após exposição às soluções nos intervalos de tempo: 5, 15 e 30 minutos, sendo as alterações microestruturais classificadas em escores, de acordo com o grau de desmineralização promovido na estrutura dentária. Resultados: Os valores de pH variaram de 2,59 (CP) a 6,24 (CN), estando as demais bebidas lácteas fermentadas abaixo do pH 3,92. Os valores de °Brix oscilaram de 0° a 19° Brix e a viscosidade variou de 2,41 mm²/s a 7,26 mm²/s. Alterações sugestivas de erosão foram evidentes nos espécimes submetidos ao CP e ao produto de menor pH. A maioria das bebidas registrou dissoluções iniciais a partir de 15 minutos, correspondendo a alterações Grau 1 (leve alteração microestrutural). Conclusão: As bebidas lácteas revelaram-se potencialmente erosivas e cariogênicas, apresentando valores de pH críticos para dissolução do esmalte, bem como presença de sólidos solúveis totais e expressiva variação de viscosidade. A análise morfológica pela MEV da superfície dentária revelou alterações microestruturais de leve a acentuada, de acordo com o tempo de exposição às bebidas.

Objective: The aim of this study was to analyze the pattern of demineralization of bovine enamel subjected to the action of fermented dairy beverages after different times and to evaluate their physical-chemical properties. Method: Six brands of dairy beverages were analyzed, having cola-type soft drink and distilled water as positive (PC) and negative (NC) controls, respectively. The pH was evaluated using a digital pH-meter and the soluble solids content (°Brix) was measured using a specific refractometer. A capillary viscometer measured the kinematic viscosity. The action of the beverages on enamel was analyzed by scanning electron microscopy (SEM) after exposure to solutions at the following time intervals: 5, 15 and 30 minutes. The microstructural alterations were scored according to the degree of demineralization observed on tooth structure. Results: The pH values ranged from 2.59 (PC) to 6.24 (NC), while the pH of the fermented dairy beverages was below 3.92. The soluble solids content values ranged from 0° to 19° Brix and viscosity ranged from 2.41 to 7.26 mm²/s. Changes suggestive of erosion were evident in the specimens submitted to the PC and to the beverage with the lowest pH. Most beverages promoted initial enamel dissolution after 15 minutes, corresponding to grade 1 alterations (mild microstructural alteration). Conclusion: The fermented dairy beverages were found to be potentially erosive and cariogenic, presenting pH values compatible with the critical value for enamel dissolution as well as total soluble solids and significant viscosity variation. Morphological analysis of tooth surface by SEM revealed microstructural changes from mild to severe, according to the exposure time to the beverages.

Avaliação do Efeito Erosivo em Microscopia Eletrônica de Varredura e Propriedades Físico-Químicas de Bebidas Gaseificadas de Baixa Caloria / Evaluation of the Erosive Effect in Scanning Electron Microscopy and Physicochemical Properties of Low-Calorie Carbonated Beverages

Objetivo: Avaliar o pH, a quantidade de Sólidos Solúveis Totais (°Brix), condutividade elétrica e a superfície do esmalte bovino submetido à ação de bebidas gaseificadas de baixa caloria, em Microscopia Eletrônica de Varredura (MEV). Material e Métodos: Os produtos utilizados foram: Aquarius Fresh® limão, H2OH!® limão, Aquazero® limão, Viver light® limão, Coca-cola® (controle positivo) e água deionizada (controle negativo). A avaliação do pH foi realizada mediante o uso de phmetro digital, a condutividade elétrica foi determinada por meio de um condutivímetro de bancada e para a quantificação do °Brix utilizou-se um refratômetro específico de campo. Para cada análise foram feitas três aferições e calculou-se a média aritmética. A superfície adamantina foi confeccionada a partir da exodontia de incisivos hígidos de maxilares bovinos de animais destinados ao abate, obtendo-se ao final, blocos de esmalte de 3x3mm (n=12) que foram submetidos ao contato por 5 minutos com as bebidas e em seguida lavados e armazenados para posterior análise em MEV. Resultados: Os valores de pH variaram de 2,56 (controle positivo) a 6,00 (controle negativo), estando as demais bebidas abaixo do pH 3,46. Os resultados para condutividade elétrica variaram de 001mS.cm -¹ (controle negativo) a 1071 mS.cm -¹ (Coca-Cola® ). Com relação aos °Brix, todas as bebidas, com exceção da Coca-Cola® (6,5°Brix) tiveram valor 0°Brix. Observou-se que as bebidas analisadas revelaram-se potencialmente erosivas. A superfície do esmalte exposto às bebidas gaseificadas apresentou características microestruturais indicativas de erosão. Conclusão: As bebidas gaseificadas analisadas se revelaram potencialmente erosivas para a superfície adamantina exposta, por um curto período de tempo, à ação destes produtos, não apresentando potencial cariogênico.

Objective: To evaluate the pH, the amount of total soluble solids (°Brix), electrical conductivity and the surface of bovine enamel, by Scanning Electronic Microscopy (SEM), subjected to the action of low- calorie soft drinks. Materials and Methods: The products tested were: Aquarius® Fresh lemon, H2OH!® lemon, Aquazero® lemon, Viver Light®lemon, CocaCola® (positive control) and deionized water (negative control). The pH evaluation was performed by using digital pHmeter. Electrical conductivity wa s determined by a workbench conductivimeter and for quantification of °Brix was used a specific refractometer of . For each analysis were made three measurements and the arithmetic mean was calculated. The adamantine surface was made from the extraction of healthy maxillary incisors from bovine animals for slaughter, resulting in the end, in 3x3mm enamel blocks (n = 12), which were submitted to contact for 5 minutes with the drinks and then washed and stored for subsequent analysis by SEM. Results: The pH values tranged from 2.56 (positive control) to 6.00 (negative control), while the remaining beverages showed pH bellow than 3.46. The results for electrical conductivity ranged from 001 mS.cm-¹ (negative control) to 1071 mS.cm- (Coca-Cola®). Considering the TSS, all beverages had a value of 0° Brix, excepting Coca-Cola® (6.5° Brix). It was observed that the beverages analyzed proved to be potentially erosive. The enamel surface exposed to fizzy drinks had microstructural features indicative of erosion. Conclusion: Fizzy drinks analyzed have proved to be potentially erosive for the adamantine surface exposed for a short period of time to the action of those products, presenting no cariogenic potential.