Biochemical properties of a Flavobacterium johnsoniae dextranase and its biotechnological potential for Streptococcus mutans biofilm degradation.

Cariogenic biofilms have a matrix rich in exopolysaccharides (EPS), mutans and dextrans, that contribute to caries development. Although several physical and chemical treatments can be employed to remove oral biofilms, those are only partly efficient and use of biofilm-degrading enzymes represents an exciting opportunity to improve the performance of oral hygiene products. In the present study, a member of a glycosyl hydrolase family 66 from Flavobacterium johnsoniae (FjGH66) was heterologously expressed and biochemically characterized. The recombinant FjGH66 showed a hydrolytic activity against an early EPS-containing S. mutans biofilm, and, when associated with a α-(1,3)-glucosyl hydrolase (mutanase) from GH87 family, displayed outstanding performance, removing more than 80% of the plate-adhered biofilm. The mixture containing FjGH66 and Prevotella melaninogenica GH87 α-1,3-mutanase was added to a commercial mouthwash liquid to synergistically remove the biofilm. Dental floss and polyethylene disks coated with biofilm-degrading enzymes also degraded plate-adhered biofilm with a high efficiency. The results presented in this study might be valuable for future development of novel oral hygiene products.

Effect of hydroxyapatite nanoparticles coating of titanium surface on biofilm adhesion: An in vitro study.

AIM: To evaluate the adhesion of mono and duospecies biofilm on a commercially available dental implant surface coated with hydroxyapatite nanoparticles (nanoHA). MATERIAL AND METHODS: Titanium discs were divided into two groups: double acid-etched (AE) and AE coated with nanoHA (NanoHA). Surface characteristics evaluated were morphology, topography, and wettability. Mono and duospecies biofilms of Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans) were formed. Discs were exposed to fetal bovine serum (FBS) to form the pellicle. Biofilm was growth in RPMI1640 medium with 10% FBS and 10% BHI medium for 6 h. Microbial viability was evaluated using colony-forming unit and metabolic activity by a colorimetric assay of the tetrazolium salt XTT. Biofilm architecture and organization were evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). RESULTS: AE surface had more pores, while NanoHA had even nanoHA crystals distribution. Roughness was similar (AE: 0.59 ± 0.07 µm, NanoHA: 0.69 ± 0.18 µm), but wettability was different (AE: Θw= 81.79 ± 8.55°, NanoHA: Θw= 53.26 ± 11.86°; P = 0.01). NanoHA had lower S. sanguinis viability in monospecies biofilm (P = 0.007). Metabolic activity was similar among all biofilms. In SEM both surfaces on C. albicans biofilm show a similar distribution of hyphae in mono and duospecies biofilms. AE surface has more S. sanguinis than the NanoHA surface in the duospecies biofilm. CLSM showed a large proportion of live cells in all groups. CONCLUSIONS: The nanoHA surface reduced the adhesion of S. sanguinis biofilm but did not alter the adhesion of C. albicans or the biofilm formed by both species.

Situational diagnosis of policies in Latin American and Caribbean countries for the use of fluoride and reduction of sugar consumption.

Policy evaluation and guidance on fluoride use and sugar consumption in Latin American and Caribbean countries (LACC) may provide a scientific evidence basis for policymakers, dental professionals, civil society organizations and individuals committed to improving public oral health. A cross-sectional study was conducted to evaluate the extent of implementation of policies/guidelines on fluoride use, and sugar consumption in LACC. The study had two stages. First a questionnaire covering four major areas was developed: fluoridation of public water supplies; salt fluoridation; fluoride dentifrices, and sugar consumption. Then, the questionnaire was applied to collect data among representative participants in public oral health from LACC. Ninety-six participants from 18 LACC answered the questionnaire. One-hundred seventy documents were attached, and 285 links of websites were provided by the respondents. Implementation of policies and guidelines on water and table salt fluoridation and processed and ultra-processed food consumption were found in most countries, with some issues in the consensus and coverage. Thus, differences were identified in the extent of implementation of public oral health strategies on sugar consumption and fluoridation among the countries. There is no consensus on the policies in LACC to reduce sugar consumption and for the use of fluoride. A few policies and guidelines were applied in isolated countries, with a variety of strategies and standards. For future actions, it will be important to encourage the development of strategies and public policies within countries, and to evaluate the effectiveness of existing policies in reducing dental caries and in improving oral health in LACC.

Recombinant Prevotella melaninogenica α-1,3 glucanase and Capnocytophaga ochracea α-1,6 glucanase as enzymatic tools for in vitro degradation of S. mutans biofilms.

Dental biofilms represent a serious oral health problem playing a key role in the development of caries and other oral diseases. In the present work, we cloned and expressed in E. coli two glucanases, Prevotella melaninogenica mutanase (PmGH87) and Capnocytophaga ochracea dextranase (CoGH66), and characterized them biochemically and biophysically. Their three-dimensional structures were elucidated and discussed. Furthermore, we tested the capacity of the enzymes to hydrolyze mutan and dextran to prevent formation of Streptococcus mutans biofilms, as well as to degrade pre- formed biofilms in low and abundant sugar conditions. The percentage of residual biofilm was calculated for each treatment group in relation to the control, as well as the degree of synergism. Our results suggest that both PmGH87 and CoGH66 are capable of inhibiting biofilm formation grown under limited or abundant sucrose conditions. Degradation of pre-formed biofilms experiments reveal a time-dependent effect for the treatment with each enzyme alone. In addition, a synergistic and dose-dependent effects of the combined enzymatic treatment with the enzymes were observed. For instance, the highest biomass degradation was 95.5% after 30 min treatment for the biofilm grown in low sucrose concentration, and 93.8% after 2 h treatment for the biofilm grown in sugar abundant condition. Strong synergistic effects were observed, with calculated degree of synergism of 5.54 and 3.18, respectively and their structural basis was discussed. Jointly, these data can pave the ground for the development of biomedical applications of the enzymes for controlling growth and promoting degradation of established oral biofilms.

In Vitro Impact of Fluconazole on Oral Microbial Communities, Bacterial Growth, and Biofilm Formation.

Antifungal agents are widely used to specifically eliminate infections by fungal pathogens. However, the specificity of antifungal agents has been challenged by a few studies demonstrating antibacterial inhibitory effects against Mycobacteria and Streptomyces species. Here, we evaluated for the first time the potential effect of fluconazole, the most clinically used antifungal agent, on a human oral microbiota biofilm model. The results showed that biofilm viability on blood and mitis salivarius agar media was increased over time in the presence of fluconazole at clinically relevant concentrations, despite a reduction in biomass. Targeted PCR revealed a higher abundance of Veillonella atypica, Veillonella dispar, and Lactobacillus spp. in the fluconazole-treated samples compared to the control, while Fusobacterium nucleatum was reduced and Streptococcus spp were not significantly affected. Further, we tested the potential impact of fluconazole using single-species models. Our results, using Streptococcus mutans and Streptococcus mitis luciferase reporters, showed that S. mutans planktonic growth was not significantly affected by fluconazole, whereas for S. mitis, planktonic growth, but not biofilm viability, was inhibited at the highest concentration. Fluconazole's effects on S. mitis biofilm biomass were concentration and time dependent. Exposure for 48 h to the highest concentration of fluconazole was associated with S. mitis biofilms with the most increased biomass. Potential growth inhibitory effects were further tested using four non-streptococcal species. Among these, the planktonic growth of both Escherichia coli and Granulicatella adiacens was inhibited by fluconazole. The data indicate bacterial responses to fluconazole that extend to a broader range of bacterial species than previously anticipated from the literature, with the potential to disturb biofilm communities.

Does Streptococcus oralis supernatant influence on the proliferation and virulence of Candida albicans?

OBJECTIVE: To evaluate the influence of Streptococcus oralis supernatant on the proliferation and virulence of Candida albicans. DESIGN: S. oralis supernatant was obtained by filtration of overnight cultures. Single or dual-species cultures of C. albicans and S. oralis were cultivated in both planktonic and biofilm-based models. Planktonic culture growth was measured, and mature biofilms formed on resin disks were collected to measure biofilm metabolic activity, total biomass, and cell counts. Hyphae formation (virulence factor) and biofilm thickness were analyzed by confocal laser scanning microscopy. Data were analyzed by a one-way ANOVA test followed by the Tukey posthoc test (α = 0.05). RESULTS: We found that S. oralis supernatant did not influence C. albicans proliferation in planktonic cultures. However, biofilms containing S. oralis supernatant showed higher cell metabolism than C. albicans monoculture biofilms and C. albicans-S. oralis dual-culture biofilms (p < 0.05). Though S. oralis supernatants did increase biofilm metabolic activity, they did not affect the total biomass and cell counts of C. albicans (p > 0.05). However, biofilm imaging revealed enhanced C. albicans hyphae formation in biofilms containing S. oralis supernatant compared to C. albicans monoculture biofilms. CONCLUSIONS: Secreted metabolites in S. oralis supernatant may contribute to C. albicans metabolism and virulence.

Candida albicans Adhesins Als1 and Hwp1 Modulate Interactions with Streptococcus mutans.

Candida albicans and Streptococcus mutans are known to synergistically interact with each other in the oral cavity. For example, glucosyltransferase B (GtfB), secreted by S. mutans, can bind to the C. albicans cell surface, promoting dual-species biofilm formation. However, the fungal factors mediating interactions with S. mutans are unknown. The C. albicans adhesins Als1, Als3, and Hwp1 are key players in C. albicans single-species biofilm formation, but their roles, if any, in interacting with S. mutans have not been assessed. Here, we investigated the roles of the C. albicans cell wall adhesins Als1, Als3, and Hwp1 on forming dual-species biofilms with S. mutans. We assessed the abilities of the C. albicans wild-type als1Δ/Δ, als3Δ/Δ, als1Δ/Δ/als3Δ/Δ, and hwp1Δ/Δ strains to form dual-species biofilms with S. mutans by measuring optical density, metabolic activity, cell enumeration, biomass, thickness, and architecture of the biofilms. We observed that the C. albicans wild-type strain formed enhanced dual-species biofilms in the presence of S. mutans in these different biofilm assays, confirming that C. albicans and S. mutans synergistically interact in the context of biofilms. Our results reveal that C. albicans Als1 and Hwp1 are major players in interacting with S. mutans, since dual-species biofilm formation was not enhanced when the als1Δ/Δ or hwp1Δ/Δ strains were cultured with S. mutans in dual-species biofilms. Als3, however, does not seem to play a clear role in interacting with S. mutans in dual-species biofilm formation. Overall, our data suggest that the C. albicans adhesins Als1 and Hwp1 function to modulate interactions with S. mutans and could be potential targets for future therapeutics.

Chapter 5.1: Physicochemical Interactions between Enamel and Oral Fluids.

Despite all the current knowledge in cariology, research is still being carried out nowadays trying to make dental enamel resistant to dental caries. Since enamel is mainly composed by a mineral, efforts have been put together to make it more resistant to acids produced by dental biofilm when exposed to dietary sugars. Fluoride was once thought to be a micronutrient that impacted caries resistance when incorporated in the tooth mineral, but we now know that the complex interactions at the mineral surface are most important. Every slightly soluble mineral, and enamel is no exception, has a behavior that is determined by the environment where it is located, and in the case of the dental crown, saliva and biofilm fluid play an important role. Enamel can keep in balance or lose its minerals, but it can gain them back. These processes, equilibrium, and loss or gain follow Le Chatelier's principle, and physicochemically, they are known as saturating, undersaturating, and supersaturating conditions, respectively. Saliva, and even the biofilm fluid, is supersaturated with calcium (Ca2+) and phosphate (PO43-) in relation to enamel solubility, and thus the natural tendency of enamel is to gain mineral, conferring saliva with a remineralizing property. However, the decrease in pH and the presence of free fluoride ion (F-) will determine what will happen to the enamel. While lowering the pH of the medium is an imbalance factor, fluoride at micromolar concentration reduces the acid impact. This chapter provides an updated, evidence-based understanding of the interactions between enamel and oral fluids.

Mechanical and surface properties of Co-Cr alloy produced by additive manufacturing for removable partial denture frameworks.

STATEMENT OF PROBLEM: Conventional analog methods have been replaced with digital methods for removable partial denture (RPD) frameworks. However, limited information is available regarding the build direction of RPD frameworks and its effect on properties. PURPOSE: The purpose of this in vitro study was to evaluate the mechanical and surface properties of the cobalt chromium (Co-Cr) alloy produced at different build angles by the laser powder bed fusion additive manufacturing (AM) technology used for RPD framework fabrication. MATERIAL AND METHODS: Plate-shaped Co-Cr specimens (n=6) were produced by the AM technology and divided into 3 groups depending on the build angle (0, 45, or 90 degrees). The elastic modulus and fracture properties were evaluated by flexural testing. Additionally, 15 disks were printed by using the same parameters of the plates (n=5) to analyze the surface hardness with microhardness testing, and surface properties were determined by surface free energy by using the contact angle and surface roughness measured by using a profilometer. Twelve Co-Cr cylindrical specimens were produced by using the same parameters (n=4), and their microstructure was examined by using an optical microscope. One-way ANOVA was used to evaluate the overall effects of the interaction between groups, and the Tukey test was applied when the interaction was statistically significant (α=.05). RESULTS: The flexural strength showed a statistically significant difference (P<.05), with the peak value exhibited by the 0-degree group. A statistical difference was also observed between the angulation and modulus of elasticity; however, the highest value was exhibited by the 45-degree group. For the fracture topography, all groups observed a dimple-like fracture, although the 45-degree group showed wider cleavage planes of fractures than other angulations. For microhardness, the 0- and 45-degree groups exhibited a statistical difference in relation to the 90-degree group (P<.05). For surface properties, no statistically significant difference (P>.05) was found in any of the evaluated parameters. Dependence on the build angles was evidenced by the molten pool boundaries during observation of the microstructure. CONCLUSIONS: The build angle influenced the flexural strength and microhardness of the Co-Cr alloy produced by AM; however, it does not affect surface free energy and surface roughness.

Dose-response relationship between toothpaste soluble fluoride absorbed in the gastrointestinal tract and saliva fluoride secretion

Aim: This study aimed to evaluate if there is a dose-response relationship between toothpaste chemically soluble fluoride absorbed in the gastrointestinal tract and fluoride secreted by saliva, giving support to the use of saliva as surrogate for plasma fluoride. Methods: A 4-phase single blind study was conducted, in which 10 participants were subjected in each phase to one of the assigned treatment groups: group I: fresh sample of a Na2FPO3/CaCO3-based toothpaste with 1,334 µg F/g of total soluble fluoride (TSF) and groups II­IV: aged samples of this toothpaste presenting TSF concentrations of 1,128, 808, and 687 µg F/g, respectively. In all phases, the participants ingested an amount of toothpaste equivalent to 70.0 µg F/Kg body weight, as total fluoride (TF). Saliva and blood samples were collected before (baseline) and up to 180 min after toothpaste ingestion as indicator of fluoride bioavailability. F concentration in saliva and blood plasma was determined with a fluoride ion-specific electrode. The areas under the curve (AUC) of F concentration versus time (AUC = ng F/mL × min) and the peaks of fluoride concentration (Cmax) in saliva and plasma were calculated. Results: A significant correlation between mg of TSF ingested and the AUC (r=0.47; p<0.01), and Cmax (r=0.59; p<0.01) in saliva was found; for TF, the correlation was not significant (p>0.05). In addition, the correlations between plasma and saliva fluoride concentrations were statistically significant for AUC (r=0.55; p<0.01) as for Cmax (r=0.68; p<0.01). Conclusion: The findings support that saliva can be used as a systemic biomarker of bioavailable fluoride present in Na2FPO3/CaCO3-based toothpaste

Situational diagnosis of policies in Latin American and Caribbean countries for the use of fluoride and reduction of sugar consumption

Abstract Policy evaluation and guidance on fluoride use and sugar consumption in Latin American and Caribbean countries (LACC) may provide a scientific evidence basis for policymakers, dental professionals, civil society organizations and individuals committed to improving public oral health. A cross-sectional study was conducted to evaluate the extent of implementation of policies/guidelines on fluoride use, and sugar consumption in LACC. The study had two stages. First a questionnaire covering four major areas was developed: fluoridation of public water supplies; salt fluoridation; fluoride dentifrices, and sugar consumption. Then, the questionnaire was applied to collect data among representative participants in public oral health from LACC. Ninety-six participants from 18 LACC answered the questionnaire. One-hundred seventy documents were attached, and 285 links of websites were provided by the respondents. Implementation of policies and guidelines on water and table salt fluoridation and processed and ultra-processed food consumption were found in most countries, with some issues in the consensus and coverage. Thus, differences were identified in the extent of implementation of public oral health strategies on sugar consumption and fluoridation among the countries. There is no consensus on the policies in LACC to reduce sugar consumption and for the use of fluoride. A few policies and guidelines were applied in isolated countries, with a variety of strategies and standards. For future actions, it will be important to encourage the development of strategies and public policies within countries, and to evaluate the effectiveness of existing policies in reducing dental caries and in improving oral health in LACC.

Demystifying interactions between micro organisms in oral candidiasis biofilm: the key to enhancing treatments

Introduction: candida albicans is a fungal pathogen that can provoke diseases ranging from oral infections to life-threatening systemic disorders. It is now recognized that oral bacteria, such as the genus Streptococcus, establish synergistic relationships with C. albicans, which could potentially increase the fungi's virulence and pathogenicity. Objective: this narrative review aimed to discuss the Candida-Streptococcus mechanisms of interactions and their contribution to increasing oral candidiasis severity. In addition, it provides a background of biofilm formation and potential therapeutical targets. Sources of Data: searches for papers in English were performed in the Pubmed database until May 2022. MeSH and free terms related to the field were used. In vitro studies were selected, tabulated, and qualitative and quantitative data were analyzed descriptively. Synthesis of Data: among the early colonizers bacteria, evidence pointed out that S. gordonnii and S. oralis have major implications in oral candidiasis, in which mixed biofilms increase the infection severity and challenge the host's defense. On the other hand, the outcomes of the interaction between C. albicans and S. mitis, S. sanguinis, or S. mutans remain little explored in the oral candidiasis scenario, albeit evidence pointed out an enhanced fungus population and virulence factors. Conclusion: overall, considering the polymicrobial profile of the infection and the potential to increase Candida-related disease severity, therapeutical strategies should also consider bacteria management.

Introdução: candida albicans é um patógeno fúngico que pode provocar doenças que variam de infecções orais a distúrbios sistêmicos com risco de vida. Hoje se reconhece que as bactérias orais, como o gênero Streptococcus, estabelecem relações sinérgicas com C. albicans, o que pode potencialmente aumentar a virulência e patogenicidade do fungo. Objetivo: esta revisão narrativa teve como objetivo discutir os mecanismos de interação Candida-Streptococcus e sua contribuição para o agravamento da candidíase oral. Além disso, fornece uma breve explanação sobre a formação do biofilme e potenciais alvos terapêuticos. Fonte dos dados: foi realizada pesquisa na base de dados Pubmed para a busca de artigos publicados em Inglês até maio de 2022. Para isso, foram utilizados descritores relacionados ao tema. Estudos in vitro foram selecionados, tabulados e seus resultados quantitativos e qualitativos analisados descritivamente. Síntese dos dados: entre as bactérias denominadas colonizadores iniciais, evidências apontam que S. gordonnii e S. oralis têm implicações importantes na candidíase oral, na qual biofilmes mistos aumentam a gravidade da infecção e desafiam a defesa do hospedeiro. Por outro lado, os desfechos das interações entre C. albicans e S. mitis, S. sanguinis ou S. mutans permanecem pouco explorados no cenário da candidíase oral, apesar de evidências apontarem um aumento dapopulação fúngica e de fatores de virulência. Conclusão: de maneira geral, considerando o perfil polimicrobiano da infecção e o potencial agravamento das doenças provocadas por Candida spp, as estratégias terapêuticas não devem estar focadas apenas no fungo, mas também devem considerar o manejo da bactéria.

Fluoride concentration in toothpaste marketed to children in Brazil and Mexico, and discussion on current regulations.

Fluoride toothpastes market to children should contain a minimum concentration of 1000 ppm of fluoride (F), which must be chemically soluble to provide anti-caries effect. Therefore, we determined the concentrations of total fluoride (TF) and total soluble fluoride (TSF) in toothpastes marketed to children in Brazil and Mexico and analyzed the current regulations in force in both countries. Twenty-four brands were found and purchased in Brazil (19 formulated with NaF/SiO2, three with Na2FPO3/CaCO3 and two with Na2FPO3/SiO2) and six in Mexico (all with NaF/SiO2). TF and TSF concentrations were determined after the purchase (fresh samples) but fluoride stability in Na2FPO3/CaCO3-formulations was checked after 18 months. The analyses were performed with an ion-specific electrode and the results expressed in ppm F (mg F/kg). The TF concentrations found ranged from 476.0 to 1385.3 ppm F and they were close the declared by the manufactures (500 to 1450 ppm F). The TF concentrations found were not greater than 1500 ppm F, in accordance with the current regulations of both countries. However, toothpastes presenting TSF concentrations lower than 1000 ppm F were found either in low fluoride toothpaste (500 ppm F) formulated with NaF/SiO2 as in fresh and aged Na2FPO3/CaCO3-toothpastes, originally fabricated with 1000-1100 ppm of TF. In conclusion, although most toothpastes analyzed showed TSF concentration higher than 1000 ppm F, the regulations in force in both countries allow that products not in agreement with the best available evidence are available in the market.

Os dentifrícios fluoretados comercializados para crianças devem conter concentração mínima de 1000 ppm de fluoreto (F), que deve ser quimicamente solúvel para ter efeito anticárie. Portanto, determinamos as concentrações de fluoreto total (FT) e fluoreto solúvel total (FST) em dentifrícios comercializados para crianças no Brasil e no México e analisamos as regulamentações vigentes em ambos os países. Vinte e quatro marcas foram encontradas e adquiridas no Brasil (19 formuladas com NaF/SiO2, três com Na2FPO3/CaCO3 e duas com Na2FPO3/SiO2) e seis no México (todas com NaF/SiO2). As concentrações de FT e FST foram determinadas após a compra (amostras frescas), e a estabilidade do fluoreto nas formulações de Na2FPO3/CaCO3 foi verificada após 18 meses. As análises foram realizadas com eletrodo íon-específico e os resultados expressos em ppm F (mg F/kg). As concentrações de FT encontradas variaram de 476,0 a 1.385,3 ppm F e foram próximas às declaradas pelos fabricantes (500 a 1.450 ppm F). As concentrações de FT encontradas não ultrapassaram 1.500 ppm F, de acordo com as regulamentações vigentes de ambos os países. No entanto, dentifrícios com concentrações de FST inferiores a 1.000 ppm F foram encontrados tanto em dentifrício com baixa concentração (500 ppm F) formulado com NaF/SiO2 como em dentifrícios com Na2FPO3/CaCO3 frescos e envelhecidos, originalmente fabricados com 1.000-1.100 ppm de FT. Em conclusão, embora a maioria dos dentifrícios analisados apresentasse concentração de FST superior a 1.000 ppm F, as regulamentações vigentes em ambos os países permitem que produtos que não estejam de acordo com a melhor evidência disponível estejam presentes no mercado.

Fluoride concentration in toothpaste marketed to children in Brazil and Mexico, and discussion on current regulations

Resumo Os dentifrícios fluoretados comercializados para crianças devem conter concentração mínima de 1000 ppm de fluoreto (F), que deve ser quimicamente solúvel para ter efeito anticárie. Portanto, determinamos as concentrações de fluoreto total (FT) e fluoreto solúvel total (FST) em dentifrícios comercializados para crianças no Brasil e no México e analisamos as regulamentações vigentes em ambos os países. Vinte e quatro marcas foram encontradas e adquiridas no Brasil (19 formuladas com NaF/SiO2, três com Na2FPO3/CaCO3 e duas com Na2FPO3/SiO2) e seis no México (todas com NaF/SiO2). As concentrações de FT e FST foram determinadas após a compra (amostras frescas), e a estabilidade do fluoreto nas formulações de Na2FPO3/CaCO3 foi verificada após 18 meses. As análises foram realizadas com eletrodo íon-específico e os resultados expressos em ppm F (mg F/kg). As concentrações de FT encontradas variaram de 476,0 a 1.385,3 ppm F e foram próximas às declaradas pelos fabricantes (500 a 1.450 ppm F). As concentrações de FT encontradas não ultrapassaram 1.500 ppm F, de acordo com as regulamentações vigentes de ambos os países. No entanto, dentifrícios com concentrações de FST inferiores a 1.000 ppm F foram encontrados tanto em dentifrício com baixa concentração (500 ppm F) formulado com NaF/SiO2 como em dentifrícios com Na2FPO3/CaCO3 frescos e envelhecidos, originalmente fabricados com 1.000-1.100 ppm de FT. Em conclusão, embora a maioria dos dentifrícios analisados apresentasse concentração de FST superior a 1.000 ppm F, as regulamentações vigentes em ambos os países permitem que produtos que não estejam de acordo com a melhor evidência disponível estejam presentes no mercado.

Abstract Fluoride toothpastes market to children should contain a minimum concentration of 1000 ppm of fluoride (F), which must be chemically soluble to provide anti-caries effect. Therefore, we determined the concentrations of total fluoride (TF) and total soluble fluoride (TSF) in toothpastes marketed to children in Brazil and Mexico and analyzed the current regulations in force in both countries. Twenty-four brands were found and purchased in Brazil (19 formulated with NaF/SiO2, three with Na2FPO3/CaCO3 and two with Na2FPO3/SiO2) and six in Mexico (all with NaF/SiO2). TF and TSF concentrations were determined after the purchase (fresh samples) but fluoride stability in Na2FPO3/CaCO3-formulations was checked after 18 months. The analyses were performed with an ion-specific electrode and the results expressed in ppm F (mg F/kg). The TF concentrations found ranged from 476.0 to 1385.3 ppm F and they were close the declared by the manufactures (500 to 1450 ppm F). The TF concentrations found were not greater than 1500 ppm F, in accordance with the current regulations of both countries. However, toothpastes presenting TSF concentrations lower than 1000 ppm F were found either in low fluoride toothpaste (500 ppm F) formulated with NaF/SiO2 as in fresh and aged Na2FPO3/CaCO3-toothpastes, originally fabricated with 1000-1100 ppm of TF. In conclusion, although most toothpastes analyzed showed TSF concentration higher than 1000 ppm F, the regulations in force in both countries allow that products not in agreement with the best available evidence are available in the market.

Soluble Fluoride in Na2FPO3/CaCO3-Based Toothpaste as an Indicator of Systemically Bioavailable Fluoride.

Fluoride chemically soluble in toothpaste is an indicator of fluoride bioavailability when the teeth are brushed, and the same should be expected systemically when toothpaste is ingested. A 4-phases study was conducted, in which 8 participants were subjected in each phase to one of the assigned treatment groups: group I: fresh sample of a Na2FPO3/CaCO3 toothpaste with 1,334 µg F/g of total soluble fluoride (TSF) and groups II-IV: aged samples of toothpaste presenting TSF concentrations of 1,128, 808, and 687 µg F/g, respectively. In all phases, the participants ingested an amount of toothpaste equivalent to 70.0 µg F/kg body weight, as total fluoride (TF). Blood was collected before (baseline) and up to 180 min after toothpaste ingestion as indicator of fluoride bioavailability. Total urine (24 h before and 24 h after ingestion) was collected as indicator of absorbed fluoride that was excreted. F concentration in blood plasma and urine was determined with a fluoride ion-specific electrode. The areas under the curve (AUC) of F concentration versus time (AUC = ng F/mL × min) and the peaks of fluoride concentration in blood plasma (Cmax) were calculated. The net amount of fluoride excreted (mg/day) was calculated by subtraction. A significant correlation of the amount (mg) of TSF ingested was found between the AUC (r = 0.76; p < 0.01) and Cmax (r = 0.86; p < 0.01) in plasma, and the fluoride excreted (r = 0.65; p < 0.01). For TF, no statistical correlations were found (p > 0.05). Data suggest that the concentration of TSF found in Na2FPO3/CaCO3-based toothpastes is a useful predictor of how much fluoride will be systemically bioavailable when this type of formulation is ingested.

Combination Effect of Diurnal Exposure to Sucrose and Nocturnal Exposure to Lactose on Enamel Demineralization.

We have hypothesized that the association between human milk and caries in breastfeeding children could be explained by the combination of a diurnal cariogenic diet with the nocturnal lactose fermentation, conditions simulated in this experimental study. Cariogenic biofilm was formed on bovine enamel slabs, which were exposed 8x/day for 3 min to a 10% sucrose solution, simulating a highly cariogenic diurnal diet, or 50 mM NaCl solution (control). Simulating the nocturnal retention of milk in mouth, biofilms were transferred to culture medium containing 0.7% lactose for 2 h, or only to culture medium (control). Four groups were designed (n = 12): Ctrl, no exposure to diurnal sucrose or nocturnal lactose; Lac, only nocturnal exposure to lactose (2 h); Suc, only diurnal exposure to sucrose (8x/day); and Suc→Lac, diurnal exposure to sucrose (8x/day) followed by nocturnal exposure to lactose (2 h). The medium was changed 3x/day, at the beginning of the day and after diurnal and nocturnal exposures. Calcium in the medium was determined as a chemical indicator of partial demineralizations occurred during the diurnal and the nocturnal treatments; the medium pH was also determined. After 96 h of growth, biofilms were harvested to evaluate CFU, biomass, and extracellular polysaccharides, soluble and insoluble. The percentage of enamel surface hardness loss (%SHL) was evaluated as cumulative demineralization. Data were analyzed by one-way ANOVA and Tukey's test (α = 5%). Highest %SHL (p < 0.05) was found for the Suc→Lac (40.6%) group when compared to Suc (32.1%), Lac (6.6%), and Ctrl (2.4%) groups. Calcium released during the diurnal and nocturnal treatments was, respectively, Suc→Lac = Suc > Lac = Ctrl and Suc→Lac > Lac > Suc = Ctrl (p < 0.05). Regarding the Ctrl group, calcium released from nocturnal lactose fermentation by the Suc→Lac group was 4-fold greater than that provoked by the Lac group. The findings were supported by the pH of the media. The data suggest that the biofilm formed under diurnal exposure to sucrose enhances the cariogenicity of nocturnal exposure to lactose.

Community interventions and strategies for caries control in Latin American and Caribbean countries.

Dental caries remains highly prevalent in Latin American and Caribbean countries (LACC). However, this disease can be controlled through interventions that implement evidence-based strategies in an affordable manner and that target all population groups instead of the most affluent only. Therefore, the aim of this report was to summarize the main scientifically documented community interventions and strategies based on restriction of sugars consumption, use of fluoride, and the use of occlusal sealants for caries control in LACC. A critical literature review was carried out in a systematic manner that included defined search strategies, independent review of the identified publications, and compilation of results in this report. Three systematic searches were conducted using the PubMed, LILACS, and SciELO databases to identify studies related to community interventions and strategies for caries control in LACC. Of the 37 publications identified, twenty-six focused on fluoride use, eight on occlusal sealant use, and three on the restriction of sugar consumption. Documented community interventions for sugars restriction were scarce in the region and were based on food supplementation, sugar replacement, and education. Thus, local and/or national policies should prioritize investment in upstream, coherent, and integrated population-wide policies such as taxes on sugary drinks and stronger regulation of advertising and promotion of sugary foods and drinks mainly targeting children. The main fluoride-based strategies used drinking water, refined domestic salt, cow milk, toothpaste and, to a lesser extent, mouth-rinses, acidulated phosphate fluoride (APF) gels, and varnishes to deliver fluoride to the population. Evidence of fluoride use was seen in Argentina, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Haiti, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Uruguay, and Venezuela. Studies reporting the use of occlusal sealants were mainly located in Brazil, Chile, Colombia, Costa Rica, Peru, Mexico, and Venezuela. Community interventions restricting sugar consumption should be implemented at the individual level and through public policies. The use of fluoride must be monitored at the local, regional, and national levels so as to achieve maximum anti-caries effect while also minimizing the risk of dental fluorosis. Moreover, fluoridated water and salt programs, used as a mutually exclusive community level strategy for caries control, should expand their benefits to reach non-covered areas of the LACC while also simultaneously providing adequate surveillance of the fluoride concentration delivered to the population. Regulating the concentration of soluble fluoride (for anti-caries effect) in dentifrice formulations is also necessary in order to provide the population with an effective strategy for disease control. Targeting culturally appropriate, economically sustainable caries control interventions to rural populations and native ethnic groups such as indigenous people, quilombolas (African-origin), and riverside Amazonian people remains a crucial challenge.

Dental caries prevalence, prospects, and challenges for Latin America and Caribbean countries: a summary and final recommendations from a Regional Consensus.

Dental caries can be effectively managed and prevented from developing into cavitated lesions while preserving tooth structure at all levels. However, the strong correlation between caries and socioeconomic factors may compromise the efficacy of preventive strategies. The high prevalence of persistent inequalities in dental caries in Latin American and Caribbean countries (LACC) is a matter of concern. The estimates of the burden of disease in some countries in this region are outdated or absent. This paper aims to summarize and present the final recommendations of a regional Consensus for Dental Caries Prevalence, Prospects, and Challenges for LACC. This consensus is based on four articles that were written by a team of Latin American experts, reviewed by dental associations, and presented and discussed in two consensus events. The following domains were explored: epidemiology, risk factors, prevention strategies, and management of dental caries with a focus on restorative procedures. Dental caries can manifest throughout the lifespan of an individual, making it a matter of concern for infants, children, adults, and older people alike. The prevalence rates of untreated caries in deciduous and permanent teeth are high in many parts of the world, including LACCs. Previous evidence suggests that the prevalence of dental caries in 12-year-olds is moderate to high in most Latin American countries. Moreover, the prevalence of treatment needs and dental caries in the adult and elderly population can also be regarded as high in this region. The risk/protective factors (e.g., sugar consumption, exposure to fluoride, and oral hygiene) probably operate similarly in all LACCs, although variations in the interplay of these factors in some countries and within the same country cannot be ruled out. Although salt and water fluoridation programs are implemented in many countries, there is a need for implementation of a surveillance policy. There is also room for improvement with regard to the introduction of minimal intervention techniques in practice and public health programs. Dental caries is a marker of social disadvantage, and oral health promotion programs and interventions aimed at reducing the burden of dental caries in LACCs must consider the complexity of the socioeconomic dynamics in this region. There is an urgent need to promote engagement of stakeholders, policymakers, medical personnel, universities, dental associations, community members, and industries to develop regional plans that enhance the oral health agenda for LACCs. A list of recommendations has been presented to underpin strategies aimed at reducing the prevalence and severity of dental caries and improving the quality of life of the impacted LACC population in the near future.

Dental caries prevalence, prospects, and challenges for Latin America and Caribbean countries: a summary and final recommendations from a Regional Consensus

Abstract Dental caries can be effectively managed and prevented from developing into cavitated lesions while preserving tooth structure at all levels. However, the strong correlation between caries and socioeconomic factors may compromise the efficacy of preventive strategies. The high prevalence of persistent inequalities in dental caries in Latin American and Caribbean countries (LACC) is a matter of concern. The estimates of the burden of disease in some countries in this region are outdated or absent. This paper aims to summarize and present the final recommendations of a regional Consensus for Dental Caries Prevalence, Prospects, and Challenges for LACC. This consensus is based on four articles that were written by a team of Latin American experts, reviewed by dental associations, and presented and discussed in two consensus events. The following domains were explored: epidemiology, risk factors, prevention strategies, and management of dental caries with a focus on restorative procedures. Dental caries can manifest throughout the lifespan of an individual, making it a matter of concern for infants, children, adults, and older people alike. The prevalence rates of untreated caries in deciduous and permanent teeth are high in many parts of the world, including LACCs. Previous evidence suggests that the prevalence of dental caries in 12-year-olds is moderate to high in most Latin American countries. Moreover, the prevalence of treatment needs and dental caries in the adult and elderly population can also be regarded as high in this region. The risk/protective factors (e.g., sugar consumption, exposure to fluoride, and oral hygiene) probably operate similarly in all LACCs, although variations in the interplay of these factors in some countries and within the same country cannot be ruled out. Although salt and water fluoridation programs are implemented in many countries, there is a need for implementation of a surveillance policy. There is also room for improvement with regard to the introduction of minimal intervention techniques in practice and public health programs. Dental caries is a marker of social disadvantage, and oral health promotion programs and interventions aimed at reducing the burden of dental caries in LACCs must consider the complexity of the socioeconomic dynamics in this region. There is an urgent need to promote engagement of stakeholders, policymakers, medical personnel, universities, dental associations, community members, and industries to develop regional plans that enhance the oral health agenda for LACCs. A list of recommendations has been presented to underpin strategies aimed at reducing the prevalence and severity of dental caries and improving the quality of life of the impacted LACC population in the near future.

Glucose effect on Candida albicans biofilm during tissue invasion.

OBJECTIVE: To evaluate, in vitro, the effect of two glucose concentrations (0.1 mM and 1.0 mM, simulating glucose concentration in saliva of healthy and diabetic individuals) on Candida albicans biofilm grown on epithelial monolayer. MATERIAL AND METHODS: C. albicans was inoculated on epithelial monolayers supplemented with 0.1 mM, 1.0 mM or no glucose. Control groups without C. albicans were also evaluated. Tissue response was assessed through the production of Interleukin-1α, Interleukin-8, Interleukin-6, Interleukin-10 and tumor necrosis factor-α. The complex of monolayer and biofilms were evaluated by quantitative reverse transcription polymerase chain reaction for expression of E-cadherin (CDH1), Caspase-3 (CASP3), ß-defensin-1 (DEFB-1) and ß-defensin-3 (DEFB-3). The biofilm architecture was visualized by confocal laser scanning microscopy. RESULTS: The production of Interleukin-1α and Interleukin-8 were increased in the presence of C. albicans (p < 0.05). Glucose did not interfere in the release of any cytokine evaluated. C. albicans downregulated transcripts for CDH1 (p < 0.05). Glucose did not induce a significant change in CDH1, CASP3, DEFB-1 and DEFB-3 messenger RNA expression. The biofilms were more structured in the presence of glucose, but no difference in the diffusion of hyphae through the epithelial cells were observed. CONCLUSIONS: The data suggest that glucose concentration does not affect the behavior of C. albicans during tissue invasion and other mechanisms must be related to the greater susceptibility of diabetic individuals to candidiasis.