Experimental toothpastes containing ß-TCP nanoparticles functionalized with fluoride and tin to prevent Erosive Tooth Wear.

OBJECTIVES: The present study aimed to synthesize toothpastes containing Beta- TriCalcium Phosphate (ß-TCP) nanoparticles, functionalized with fluoride and tin, and test their ability to reduce erosive tooth wear (ETW). METHODS: Toothpastes were synthesized with the following active ingredients: 1100 ppm of fluoride (as sodium fluoride, F-), 3500 ppm of tin (as stannous chloride, Sn2+), and 800 ppm of ß-TCP (Sizes a - 20 nm; and b - 100 nm). Enamel specimens were randomly assigned into the following groups (n = 10): 1. Commercial toothpaste; 2. Placebo; 3 F-; 4. F- + ß-TCPa; 5. F- + ß-TCPb; 6. F- + Sn2+; 7. F- + Sn2+ + ß-TCPa and 8. F- + Sn2+ + ß-TCPb. Specimens were subjected to erosion-abrasion cycling. Surface loss (in µm) was measured by optical profilometry. Toothpastes pH and available F- were also assessed. RESULTS: Brushing with placebo toothpaste resulted in higher surface loss than brushing with F- (p = 0.005) and F- + ß-TCPb (p = 0.007); however, there was no difference between F- and F- + ß-TCPb (p = 1.00). Commercial toothpaste showed no difference from Placebo (p = 0.279). The groups F-, F- + ß-TCPa, F- + ß-TCPb, F- + Sn2+, F- + Sn2+ + ß-TCPa and F- + Sn2+ + ß-TCPb were not different from the commercial toothpaste (p > 0.05). Overall, the addition of ß-TCP reduced the amount of available fluoride in the experimental toothpastes. The pH of toothpastes ranged from 4.97 to 6.49. CONCLUSIONS: Although toothpaste containing ß-TCP nanoparticles protected enamel against dental erosion-abrasion, this effect was not superior to the standard fluoride toothpaste (commercial). In addition, the functionalization of ß-TCP nanoparticles with fluoride and tin did not enhance their protective effect. CLINICAL SIGNIFICANCE: Although ß-TCP nanoparticles have some potential to control Erosive Tooth Wear, their incorporation into an experimental toothpaste appears to have a protective effect that is similar to a commercial fluoride toothpaste.

Characteristics of tin-containing fluoride toothpastes related to erosive tooth wear protection.

OBJECTIVES: To assess the effect of different tin-containing toothpastes on the control of erosive tooth wear in enamel and dentin. METHODS: Enamel and dentin slabs were randomly distributed into 7 experimental groups (n = 10/substrate): C-: negative control (Artificial saliva); AmF (regular fluoridated toothpaste without tin); Sn-1 (SnF2/NaF); Sn-2 (SnF2/NaF/SnCl2); Sn-3 (SnCl2/NaF); Sn-4 (SnF2/SnCl2); Sn-5 (SnCl2/AmF/NaF/chitosan). Specimens were submitted to 5-day erosion-abrasion cycling. Surface loss (SL) was determined with an optical profilometer. Tin deposition on the tooth surfaces and some characteristics of the toothpastes (pH, potentially available F-, %weight of solid particles, and RDA) were also assessed. Data were statistically analyzed (α = 0.05). RESULTS: For enamel, the Sn-2 presented the lowest SL, not differing significantly from AmF, C+, and Sn-3. The SL of these groups was significantly lower than the C-, except for Sn-3. Sn-1 and Sn-4 were also not significantly different from C-. For dentin, C- significantly showed the highest SL values, whilst, Sn-1 presented the lowest SL, not differing significantly from AmF, Sn-2, C+, and Sn-3. There was a significant positive association between enamel SL and the pH and tin deposition. Dentin SL was significantly negatively associated with the %weight of solid particles and RDA. CONCLUSIONS: Most of the tin-toothpastes were able to exhibit some protection against ETW. In this process, the toothpastes characteristics play a role, as lower enamel SL was significantly associated with lower pH values and tin deposition; and lower dentin SL was associated with higher %weight of solid particles and RDA of the toothpastes. CLINICAL SIGNIFICANCE: Tin-containing toothpastes can be used for erosive tooth wear protection, but our study showed that their effect depends on the pH, amount of tin deposition, % weight of solid particles and RDA of the toohpastes.

Avaliação de um gel contendo fluoreto e estanho como uma opção de tratamento profissional para o controle da erosão do esmalte e da dentina / Evaluation of a gel containing fluoride and stannous as an option for the professional treatment of enamel and dentin erosion

Este estudo teve o objetivo de desenvolver um gel experimental contendo flúor e estanho, como uma opção de tratamento profissional, para ser utilizado na prevenção da erosão dental. Foram utilizados 50 fragmentos (4mm × 4mm × 2mm) de esmalte e 50 de dentina, obtidos de incisivos bovinos. Os fragmentos foram incluídos em resina acrílica, planificados e polidos. Em seguida, uma fita adesiva foi posicionada sobre a superfície polida desses espécimes, deixando uma janela de 4mm × 1mm exposta aos testes subsequentes. Os espécimes foram previamente erodidos (10min em solução de ácido cítrico a 1%, pH~2,4) e distribuídos aleatoriamente em cinco grupos experimentais (n=10 para cada substrato), de acordo com os seguintes tratamentos: 1. F+Sn+HPMC: Gel de fluoreto de sódio e cloreto de estanho experimental (7500 ppm F- e 15000 ppm Sn2+, pH=4,5); 2. F+HPMC: Gel de fluoreto de sódio experimental (7500 ppm F-, pH=4,5); 3. Comercial: Gel de flúor fosfato acidulado comercial - APF (12300 ppm F-, pH=3,2); 4. Placebo: Gel placebo (Hidroxipropil MetilceluloseHPMC, sem componentes ativos); 5. Controle negativo: sem tratamento; aplicados por 60 s. Na sequência, os espécimes foram submetidos a uma ciclagem de erosão-re-deposição mineral, que consistia em 5 min de imersão em solução de ácido cítrico a 0,3% (pH~2,6), seguido de imersão em saliva artificial por 60min, 4x/dia, durante 5 dias. A perda de superfície dos espécimes (PS em m) foi determinada com um perfilômetro óptico após 5, 10 e 20 dias de ciclagem. Os dados obtidos foram analisados com ANOVA de dois fatores de medidas repetidas, considerando um nível de significância de 5%. Para o esmalte, o placebo não diferiu do controle em nenhum tempo experimental, e ambos apresentaram significativamente a maior PS. Após 5 e 10 dias: (F+Sn+HPMC)=(comercial)<(F+HPMC)<(placebo)=(controle). Após 20 dias: (F+Sn+HPMC)=(F+HPMC)=(comercial)<(controle)=(placebo). Para dentina, no 5º dia: (comercial)=(F+Sn+HPMC)=(F+HPMC)<(controle)=(placebo). No 10º dia, os grupos F+Sn+HMC, comercial e F+HPMC continuaram apresentando menor PS do que o controle e o placebo, porém, F+HPMC não diferiu significativamente desses dois últimos grupos. No 20º dia, somente o comercial apresentou menor PS que controle e placebo. Considerando as limitações desse estudo in vitro, pode-se concluir que o gel de F+Sn+HPMC foi capaz de controlar a progressão da erosão dental de maneira semelhante ao gel comercial, que possui 4800 ppm a mais de fluoreto em sua composição, exceto após 20 dias de desafio erosivo na dentina. Esse gel é uma alternativa clínica viável, podendo ser potencialmente utilizado em conjunto com produtos de uso diário, visando o aumento da proteção contra erosão em indivíduos com alto risco para erosão dental.

Toxic Metals and Metalloids in Infant Formulas Marketed in Brazil, and Child Health Risks According to the Target Hazard Quotients and Target Cancer Risk.

Children are highly vulnerable to chemical exposure. Thus, metal and metalloid in infant formulas are a concern, although studies in this regard are still relatively scarce. Thus, the presence of aluminum, arsenic, cadmium, tin, mercury, lead, and uranium was investigated in infant formulas marketed in Brazil by inductively coupled plasma mass spectrometry, and the Target Hazard Quotients (THQ) and Target Cancer Risk (TCR) were calculated in to assess the potential risk of toxicity for children who consume these products continuously. Aluminum ranging from 0.432 ± 0.049 to 1.241 ± 0.113 mg·kg-1, arsenic from 0.012 ± 0.009 to 0.034 ± 0.006 mg·kg-1, and tin from 0.007 ± 0.003 to 0.095 ± 0.024 mg·kg-1 were the major elements, while cadmium and uranium were present at the lowest concentrations. According to the THQ, arsenic contents in infant formulas showed a THQ > 1, indicating potential health risk concerns for newborns or children. Minimal carcinogenic risks were observed for the elements considered carcinogenic. Metabolic and nutritional interactions are also discussed. This study indicates the need to improve infant formula surveillance concerning contamination by potentially toxic and carcinogenic elements.

Organotin contamination in seafood from the Yucatán Peninsula, Mexico: Is there a potential risk for the health of consumers?

Since seafood is considered an important source of organotin compounds (OTCs), the present study assessed the potential risk to human health of ingesting butyltins (BTs) and phenyltins (PhTs) along with this type of food. Seafood samples were collected at five fishing sites in the Yucatán Peninsula (Mexico) during February and March 2018. In general, organotins were detected in all samples, suggesting a widespread occurrence of these compounds in the investigated region. The average concentration of total organotins in the muscle of demersal fish (Lutjanus synagris, Lutjanus campechanus, Calamus pennatula, Haemulon plumierii, Rhomboplites aurorubens), pelagic fish (Euthynnus alletteratus, and Opisthonema oglinum), gastropods (Melongena bispinosa and Strombus pugilis), oyster (Crassostrea virginica) and shrimp (Penaeus duorarum) was 146.7 ± 76.2, 93.1 ± 92.6, 61.0 ± 53.0, 76.7 ± 2.6, and 28.8 ± 2.7 ng Sn g-1 dry weight, respectively. Overall, MPhT among PhTs was the dominant compound in fish, while TBT among BTs was the dominant compound in shellfish. Regarding the toxic OTCs, TBT followed by DBT were the predominant compounds in all seafood species, while TPhT was below the quantification limit in most samples. The estimated daily intake values were lower than the tolerable daily intake (TDI) for the sum of organotins established by the European Food Safety Authority (EFSA). Furthermore, the hazard quotients (HQ) and hazard indices (HI) values were all lower than 1, suggesting that daily exposure to these levels of organotins is unlikely to cause any harm to the human health of seafood consumers at the Yucatán Peninsula. Thus, consumers may not be at risk through the inclusion of these investigated seafood species in their normal diet. However, due to the increasing coastal urbanization, maritime activities, and the likely illegal use of tin-based paints in Mexico, additional monitoring is needed to assess organotin levels in other regions along the Mexican coastal zone and using other seafood species.

Metal exposure and breast cancer among Northern Mexican women: assessment of genetic susceptibility.

This study aims to assess breast cancer (BC) association with metals and whether polymorphisms in CYP1A1, CYP1B1, GSTM1 and GSTT1 act as confounders or as modifiers of those relationships. We performed a secondary analysis of 499 histologically confirmed BC cases and the same number of age-matched population controls. We measured urinary concentrations of 18 metals with mass spectrometry. We determined the genetic variants of interest by allelic discrimination and multiplex PCR. After adjusting for covariates, we found BC negatively associated with arsenic, barium, cobalt, copper, magnesium, molybdenum and vanadium concentrations and positively with those of caesium, manganese, tin and thallium. Most associations remained after stratifying by the genetic variants. We identified that polymorphisms in CYP1B1, CYP1A1 and GSTM1 genes interacted with some metals on BC: interaction p-values CYP1B1 G119T × antimony= 0.036, CYP1B1 G119T × cobalt <0.001, CYP1B1 G119T × tin= 0.032, CYP1A1 A4889G × aluminium= 0.018, CYP1A1 A4889G × arsenic= 0.031, CYP1A1 A4889G × nickel= 0.036, CYP1A1 A4889G × vanadium= 0.031 and GSTM1 deletion × barium= 0.035. Exposure to various individual metals, along with genetic characteristics may contribute to BC development. Further studies are warranted to confirm our results.

Disposition of trace elements in the mangrove ecosystem and their effects on Ucides cordatus (Linnaeus, 1763) (Crustacea, Decapoda).

The tropical mangrove at the Estação Ecológica do Lameirão (Southeastern Brazil), an ecosystem of high socio-economic value, receives a large load of pollutants from domestic, industrial, and agricultural sources. Samples of interstitial water, sediments, and crustacean specimens were collected at different periods and regions throughout the study area to measure the concentrations of copper (Cu), cadmium (Cd), lead (Pb), and tin (Sn) along the mangrove, as well as the bioaccumulation behavior in the crab Ucides cordatus. Subsequently, we correlated the accumulation of metals in U. cordatus with the concentrations of metals in the environment and physicochemical and climatic factors. Furthermore, we compared the bioconcentration factors (BFCs) of trace elements with the concentration levels obtained from the mangrove sediment. The fluctuation of rain and tide throughout the study period caused oscillations in the concentrations of trace elements. This condition induced bioconcentration records (BFC > 1), influencing the bioaccumulation trend in U. cordatus. We also identified that the lowest metal concentration values in the sediment were close to the river, indicating that the rivers cause a dilution effect. Finally, we found that the hepatopancreas had the highest levels of bioaccumulated heavy metals, explained by its detoxifying ability. In females of U. cordatus, we found a slightly lower accumulation of trace elements when compared to males, possibly related to the high rate of ecdysis in females. Ucides cordatus is a species widely used for human consumption. Our results show that the mangrove environment influences the concentration of trace elements in this organism, which the authorities should consider in mapping safer fishing areas.

Avaliação de um gel contendo fluoreto e estanho como uma opção de tratamento profissional para o controle da erosão do esmalte e da dentina / Evaluation of a gel containing fluoride and stannous as an option for the professional treatment of enamel and dentin erosion

Este estudo teve o objetivo de desenvolver um gel experimental contendo flúor e estanho, como uma opção de tratamento profissional, para ser utilizado na prevenção da erosão dental. Foram utilizados 50 fragmentos (4mm × 4mm × 2mm) de esmalte e 50 de dentina, obtidos de incisivos bovinos. Os fragmentos foram incluídos em resina acrílica, planificados e polidos. Em seguida, uma fita adesiva foi posicionada sobre a superfície polida desses espécimes, deixando uma janela de 4mm × 1mm exposta aos testes subsequentes. Os espécimes foram previamente erodidos (10min em solução de ácido cítrico a 1%, pH~2,4) e distribuídos aleatoriamente em cinco grupos experimentais (n=10 para cada substrato), de acordo com os seguintes tratamentos: 1. F+Sn+HPMC: Gel de fluoreto de sódio e cloreto de estanho experimental (7500 ppm F- e 15000 ppm Sn2+, pH=4,5); 2. F+HPMC: Gel de fluoreto de sódio experimental (7500 ppm F-, pH=4,5); 3. Comercial: Gel de flúor fosfato acidulado comercial - APF (12300 ppm F-, pH=3,2); 4. Placebo: Gel placebo (Hidroxipropil MetilceluloseHPMC, sem componentes ativos); 5. Controle negativo: sem tratamento; aplicados por 60 s. Na sequência, os espécimes foram submetidos a uma ciclagem de erosão-re-deposição mineral, que consistia em 5 min de imersão em solução de ácido cítrico a 0,3% (pH~2,6), seguido de imersão em saliva artificial por 60min, 4x/dia, durante 5 dias. A perda de superfície dos espécimes (PS em m) foi determinada com um perfilômetro óptico após 5, 10 e 20 dias de ciclagem. Os dados obtidos foram analisados com ANOVA de dois fatores de medidas repetidas, considerando um nível de significância de 5%. Para o esmalte, o placebo não diferiu do controle em nenhum tempo experimental, e ambos apresentaram significativamente a maior PS. Após 5 e 10 dias: (F+Sn+HPMC)=(comercial)<(F+HPMC)<(placebo)=(controle). Após 20 dias: (F+Sn+HPMC)=(F+HPMC)=(comercial)<(controle)=(placebo). Para dentina, no 5º dia: (comercial)=(F+Sn+HPMC)=(F+HPMC)<(controle)=(placebo). No 10º dia, os grupos F+Sn+HMC, comercial e F+HPMC continuaram apresentando menor PS do que o controle e o placebo, porém, F+HPMC não diferiu significativamente desses dois últimos grupos. No 20º dia, somente o comercial apresentou menor PS que controle e placebo. Considerando as limitações desse estudo in vitro, pode-se concluir que o gel de F+Sn+HPMC foi capaz de controlar a progressão da erosão dental de maneira semelhante ao gel comercial, que possui 4800 ppm a mais de fluoreto em sua composição, exceto após 20 dias de desafio erosivo na dentina. Esse gel é uma alternativa clínica viável, podendo ser potencialmente utilizado em conjunto com produtos de uso diário, visando o aumento da proteção contra erosão em indivíduos com alto risco para erosão dental.

Novel polymethyl methacrylate modified with metal methacrylate monomers: biological, physicomechanical, and optical properties.

This study sought to evaluate the physical and antimicrobial properties of a thermopolymerizable acrylic resin (PMMA) modified with metallic methacrylate monomers -zirconia (ZM), tin (TM), and di-n-butyl (DNTMB) methacrylates. Color stability was evaluated before and after immersion of samples in a staining solution by a digital spectrophotometer. The mechanical brushing test was evaluated by the roughness test. The flexural strength test used a mechanical testing machine. Human keratinocytes were used to assess cell viability and the biofilm formation assay was carried out for 5 days, in a microcosms model after one year of specimen storage. For statistical analysis, the method chosen was based on adherence to the normal distribution model and equality of variances (p < 0.05). The addition of DNTMB to PMMA promoted great antimicrobial action, acceptable cytocompatibility, without hampering the physical-mechanical properties of the commercial material. Therefore, the modified PMMA proved to be a promisor alternative to conventional resins.This study sought to evaluate the physical and antimicrobial properties of a thermopolymerizable acrylic resin (PMMA) modified with metallic methacrylate monomers -zirconia (ZM), tin (TM), and di-n-butyldimethacrylate-tin (DNTMB) methacrylates. Color stability was evaluated before and after immersion of samples in a staining solution using a digital spectrophotometer. The mechanical brushing test was evaluated by the roughness test. The flexural strength test used a mechanical testing machine. Human keratinocytes were used to assess cell viability and the biofilm formation assay was carried out for 5 days in a microcosm model after one year of specimen storage. For statistical analysis, the method chosen was based on adherence to the normal distribution model and equality of variances (p < 0.05). The addition of DNTMB to PMMA promoted great antimicrobial action, acceptable cytocompatibility, without hampering the physical-mechanical properties of the commercial material. Therefore, the modified PMMA proved to be a promising alternative to conventional denture base resins for dental use.

Breast cancer and urinary metal mixtures in Mexican women.

Humans are environmentally exposed to many metals throughout their lives. Simultaneous exposure to several metals could result in synergistic or antagonistic toxicological effects among them; however, the information on exposure to mixtures of metals and breast cancer (BC) is scarce. The objective of this report was to compare metals considered human carcinogens, individually and as mixtures, in women with and without BC. This is a secondary analysis of a population-based case-control study that was carried out from 2007 to 2011 in Northern Mexico. A total of 499 histologically confirmed BC cases and 499 controls were included. Information about sociodemographic, lifestyle and reproductive characteristics was obtained by in-person interviews. Urinary concentrations of aluminum (Al), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), antimony (Sb), cobalt (Co), molybdenum (Mo), tin (Sn), and vanadium (V) were determined by inductively coupled plasma triple quadrupole. Metal mixtures were identified by principal component analysis with creatinine-corrected metals. Over 90% of subjects had metal measurements above the detection limit except tin (86%) and antimony (78.4%). After adjusting by selected covariables, we observed that the individual urinary concentrations of V, Co, and Mo were lower among cases compared to controls; in contrast to Sn that had higher concentrations. We identified two principal component mixtures with opposite relationships with BC: Cr, Ni, Sb, Al, Pb and Sn (OR = 1.15; CI95% 1.06,1.25) and Mo and Co (OR = 0.56; CI95% 0.49,0.64). This is the first study that identified urinary metal mixtures that differed between women with and without BC. Our results warrant confirmation in further prospective epidemiological studies. In addition, the elucidation of underlying mechanisms of metal interactions on BC risk deserves further research.

Low Mg content on Ti-Nb-Sn alloy when in contact with eBMMSCs promotes improvement of its biological functions.

Magnesium is a metal used in the composition of titanium alloys and imparts porosity. Due to its osteoconductive, biocompatible and biodegradable characteristics, its application in the development of biomedical materials has become attractive. This study aimed to evaluate the influence of magnesium present in porous Ti-Nb-Sn alloys, which have a low elastic modulus in adhesive, osteogenic properties and the amount of reactive intracellular oxygen species released in mesenchymal stem cells derived from bone marrow equine bone (eBMMSCs). Mechanical properties of the alloy, such as hardness, compressive strength and elastic modulus, were analyzed, as well as surface morphological characteristics through scanning electron microscopy. The evaluation of magnesium ion release was performed by atomic force spectroscopy. The biological characteristics of the alloy, when in contact with the alloy surface and with the culture medium conditioned with the alloy, were studied by SEM and optical microscopy. Confirmation of osteogenic differentiation by alizarin red and detection of ROS using a Muse® Oxidative Stress Kit based on dihydroetide (DHE). The alloy showed an elastic modulus close to cortical bone values. The hardness was close to commercial Ti grade 2, and the compressive strength was greater than the value of cortical bone. The eBMMSCs adhered to the surface of the alloy during the experimental time. Osteogenic differentiation was observed with the treatment of eBMMMSCs with conditioned medium. The eBMMSCs treated with conditioned medium decreased ROS production, indicating a possible antioxidant defense potential of magnesium release.

Total tin (TSn) biomagnification: Evaluating organotin trophic flow and dispersion using hepatic TSn concentrations and stable isotope (C, N) data of nektonic organisms from Brazil.

A previous investigation of our research team has demonstrated the suitability of using hepatic total tin (ΣSn) concentrations for evaluating dolphin exposure to organotins (OTs). The present study develops the previous technique into three different approaches that comprise data: (1) on hepatic ΣSn concentrations of 121 Guiana dolphins (Sotalia guianensis) from five different coastal areas (CAs): (2) on ΣSn, δ13C and δ15N for 40 dolphins from Rio de Janeiro state (RJ), including ten different delphinid species; as well as (3) on hepatic ΣSn concentrations and δ15N values on 31 individuals from five different fish species from Sepetiba Bay (SB, Rio de Janeiro-RJ, Brazil). Hepatic ΣSn concentrations of Guiana dolphins from Guanabara Bay (GB, RJ) were significantly higher than those found in other four CAs from S and SE Brazilian regions. Significant positive correlations were found between ΣSn concentrations and δ13C data in delphinid species, demonstrating a coast-ocean gradient in dolphin exposure to OTs in RJ state. Significant and positive correlations were observed between ΣSn concentrations and both δ15N and Trophic Position (TP) values of fish, as well as high values were found for Trophic Magnification Factor (TMF = 3.03) and Trophic Magnification Slope (TMS = 0.14), demonstrating OT biomagnification in SB ichthyofauna.

Intestinal Parasites, Anemia and Nutritional Status in Young Children from Transitioning Western Amazon.

Young children are particularly vulnerable to the chronic sequelae of anemia, including poor nutritional status. The aim of this study was to assess intestinal parasitic-infections and nutritional status (anemia and linear growth) in preschool children living in contemporary Amazonian communities. A cross-sectional study measured children's intestinal parasites and hair-Hg (HHg)-biomarkers of fish consumption, hemoglobin levels, and growth (anthropometric Z-scores). Children came from traditional-living families (Itapuã), and tin-mining settlements (Bom Futuro) representing current transitioning populations. It covered 937 pre-school children (from 1 to 59 months of age) from traditional (247) and immigrant tin-mining families (688). There was a high prevalence of intestinal polyparasitic-infection in children from both communities, but mild anemia (hemoglobin concentrations) and moderate (chronic) malnutrition were more frequent in children from traditional families than in children from tin-mining settlers. Children from traditional families ate significantly more fish (HHg mean of 4.3 µg/g) than children from tin-mining families (HHg mean of 2.3 µg/g). Among traditional villagers, children showed a significant correlation (r = 0.2318; p = 0.0005) between hemoglobin concentrations and HHg concentrations. High rates of parasitic infection underlie the poverty and attendant health issues of young children in the Brazilian Amazon. The intestinal parasite burden affecting poor Amazonian children resulting from unsafe water, lack of sanitation and poor hygiene is the most urgent environmental health issue.

Influência da película adquirida e do momento da aplicação da solução de AmF/NaF/SnCl2 na progressão da lesão de erosão em esmalte / Influence of the acquired pellicle and the moment of application of the AmF/NaF/SnCl2 solution in the prevention of in situ erosion in human enamel

Considerando que a capacidade protetora da película salivar adquirida em erosão dental pode ser influenciada por diversos fatores, e que a característica da película adquirida pode modificar a deposição de sais na superfície do esmalte dental, é importante avaliar se sua presença é capaz de influenciar a eficácia da solução de AmF/NaF/SnCl2 no controle da erosão dental. A primeira etapa do estudo, in vitro, teve como objetivo obter um protocolo simplificado de formação da lesão erosiva em esmalte dental humano, variando a concentração do ácido, frequência e duração das imersões erosivas. Para tanto, 64 amostras de esmalte dental humano foram divididas em 8 grupos experimentais (n=8), de acordo com a ciclagem proposta: G1 - ácido cítrico 0,5%, 3x/dia, 2 min; G2 - ácido cítrico 0,5%, 6x/dia, 2 min; G3 - ácido cítrico 0,5%, 3x/dia, 5 min; G4 - ácido cítrico 0,5%, 6x/dia, 5 min; G5 - ácido cítrico 1%, 3x/dia, 2 min; G6 - ácido cítrico 1%, 6x/dia, 2 min; G7 - ácido cítrico 1%, 3x/dia, 5 min; G8 - ácido cítrico 1%, 6x/dia, 5 min. A variável de resposta foi a perda de tecido mineral (em ?m) por meio de perfilometria óptica. Anova 1-fator mostrou que houve diferença estatística entre os grupos, (p?0,01) e Tukey mostrou que apenas G2 e G3 foram semelhantes e todos os demais grupos diferiram entre si. Sendo assim, foi escolhida para a etapa in situ a ciclagem considerada mais simples, semelhante ao G7, mas que mantivesse o padrão de lesão erosiva avançada. A segunda etapa do estudo, in situ, foi delineada para avaliar se a película adquirida e o momento da aplicação interferem na ação da solução de AmF/NaF/SnCl2 no controle da erosão. Doze participantes, utilizando um dispositivo removível inferior bilateral contendo 2 amostras de esmalte dental humano, participaram deste estudo in situ, cruzado, duplo cego, dividido em 3 fases de 5 dias cada (boca dividida). Cento e quarenta e quatro amostras de esmalte dental humano (3 X 3 X 1 mm), obtidas a partir de terceiros molares hígidos, foram divididas nos 6 grupos experimentais (n = 12): G1 - sem tratamento, com presença de película adquirida; G2 - sem tratamento, sem presença da película adquirida; G3 - Aplicação da solução de AmF/NaF/SnCl2 previamente à 1ª imersão ácida diária, com presença de película adquirida; G4 - Aplicação da solução de AmF/NaF/SnCl2 previamente à 1ª imersão ácida diária, sem película adquirida; G5 - Aplicação da solução de AmF/NaF/SnCl2 logo após a 1ª imersão ácida diária, com presença de película adquirida; G4 - Aplicação da solução de AmF/NaF/SnCl2 logo após a 1ª imersão ácida diária, sem película adquirida. Desafios erosivos (ácido cítrico a 1,0%, pH 2,3, 4x5 min/dia, intervalos de 1,5h) e remoção da película adquirida (2% de Dodecil Sulfato de Sódio) foram realizados extraoralmente, enquanto o bochecho foi realizado intraoralmente (30 seg). A perda tecidual foi determinada por perfilometria óptica (n = 12) e alterações morfológicas por microscopia eletrônica de varredura (n = 3). Os dados foram analisados estatisticamente por ANOVA 2-fatores para blocos casualizados com posterior comparação pareada dos tratamentos através do teste de Tukey (?=5%). Não houve interação significativa entre as variáveis independentes "Tipo de Tratamento" e "Película Adquirida" (p = 0,211). Considerando o fator principal "Tipo de Tratamento", quando comparado ao grupo sem tratamento, o desgaste do esmalte foi estatisticamente menor com a aplicação de solução de estanho (p <0,001), independentemente de ter sido aplicado antes ou após a 1ª imersão ácida diária, seja em presença ou ausência de película. Portanto, a presença de película adquirida e o momento de aplicação da solução de AmF/NaF/SnCl2 não influenciaram a sua capacidade de controlar a erosão em esmalte dental no presente modelo experimental.

Spatial pattern of the environmental exposure to tin in the vicinity of an alloy industry in Volta Redonda, Rio de Janeiro State, Brazil.

Despite being widely used in industry, the literature on tin and its effects in humans is scarce, especially regarding reference values in biological indicators such as blood and urine. Similarly, environmental limits are also rare. This study sought to assess the spatial distribution of hotspots in the environmental exposure to tin in the vicinity of an alloy industry in the south region of the state of Rio de Janeiro, Brazil. The study population consisted of 74 adults. Graphite furnace atomic absorption spectrometry determined tin in all samples. Households and points around the industry were georeferenced with the use of GPS to identify the most intense tin sites. Results of the first and second campaigns ranged from 0.022 to 0.153 and 0.003 to 0.445µg m-3 for the atmospheric air, whereas such ranges were 0.64 to 1.61 and 1.97 to 8.54µg m-2 for household dust, respectively. The mean tin concentration found in the blood of the population was 3.85 ± 1.57µg L-1. In urine the value was 3.56 ± 1.88µg L-1. The kernel map showed the highest spatial concentrations of tin in household dust in the eastern region of the industry. In the first sampling, atmospheric air samples presented the most elevated concentrations in the southwest and southeast. Although the direction of the wind was northwest, potentially high risks were concentrated in the central area in the second collection. The largest hotspots were in the north, south and southeast regions; however, urine samples showed medium to high levels in the west and east regions. Regarding blood samples, the greatest difference was the absence of hotspot areas in the west. Environmental monitoring becomes necessary to better assess the exposure to tin.

Indium and tin recovery from waste LCD panels using citrate as a complexing agent.

In this work, an environmentally-friendly leaching process for the recovery of indium (In) and tin (Sn) from LCD panel waste was investigated. Easily degradable citrates (C6H5O73-), i.e., sodium citrate and citric acid, were used as complexing agents. The morphology and composition of the species present in the LCD powder before and after the leaching processes were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The concentrations of In, Sn, and iron (Fe) present in the leachate were determined by atomic absorption spectrometry (AAS). The necessary thermodynamic conditions for achieving substantial In recovery were established by using MEDUSA software. The optimal process conditions were determined experimentally by varying the initial citrate concentration as well as by using reducing or oxidizing media, respectively hydrazine (N2H4) or hydrogen peroxide (H2O2). It was found that using N2H4 in a citrate solution as a reducing agent enhances the leaching efficiency. However, high concentrations of Sn and Fe with respect to In were found in the LCD powder. Therefore, a pretreatment processes to first remove the excess of Sn and Fe, which compete with In for the citrate, was implemented. Leaching with 1 M citrate, 0.2 M N2H4, at pH = 5, using sodium hydroxide (NaOH) at solid:liquid (S:L) ratio of 20 g∙L-1, yielded a remarkably high In recovery of 98.9% after 16.6 h.

Subcellular metal distributions and metallothionein associations in rough-toothed dolphins (Steno bredanensis) from Southeastern Brazil.

Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.

Spatial pattern of the environmental exposure to tin in the vicinity of an alloy industry in Volta Redonda, Rio de Janeiro State, Brazil / Padrão espacial da exposição ambiental ao estanho nos arredores de uma indústria de ligas metálicas em Volta Redonda, Estado do Rio de Janeiro, Brasil / Patrón espacial de exposición ambiental al estaño en las proximidades de una industria de aleación en Volta Redonda, estado de Río de Janeiro, Brasil

Abstract: Despite being widely used in industry, the literature on tin and its effects in humans is scarce, especially regarding reference values in biological indicators such as blood and urine. Similarly, environmental limits are also rare. This study sought to assess the spatial distribution of hotspots in the environmental exposure to tin in the vicinity of an alloy industry in the south region of the state of Rio de Janeiro, Brazil. The study population consisted of 74 adults. Graphite furnace atomic absorption spectrometry determined tin in all samples. Households and points around the industry were georeferenced with the use of GPS to identify the most intense tin sites. Results of the first and second campaigns ranged from 0.022 to 0.153 and 0.003 to 0.445µg m-3 for the atmospheric air, whereas such ranges were 0.64 to 1.61 and 1.97 to 8.54µg m-2 for household dust, respectively. The mean tin concentration found in the blood of the population was 3.85 ± 1.57µg L-1. In urine the value was 3.56 ± 1.88µg L-1. The kernel map showed the highest spatial concentrations of tin in household dust in the eastern region of the industry. In the first sampling, atmospheric air samples presented the most elevated concentrations in the southwest and southeast. Although the direction of the wind was northwest, potentially high risks were concentrated in the central area in the second collection. The largest hotspots were in the north, south and southeast regions; however, urine samples showed medium to high levels in the west and east regions. Regarding blood samples, the greatest difference was the absence of hotspot areas in the west. Environmental monitoring becomes necessary to better assess the exposure to tin.

Resumo: O estanho é amplamente utilizado na indústria. A literatura sobre seus efeitos em humanos é escassa, principalmente quanto aos valores de referência em indicadores biológicos como sangue e urina. Também são raros os estudos sobre os limites do estanho no meio ambiente. O estudo teve como objetivo avaliar os pontos críticos da distribuição espacial da exposição ambiental ao estanho nos arredores de uma indústria de ligas metálicas na região sul do Estado do Rio de Janeiro, Brasil. A população do estudo consistiu em 74 adultos. O estanho foi medido em todas as amostras com a espectrometria de absorção atômica em forno de grafite. As residências e outros pontos em torno da indústria foram georreferenciados com GPS para identificar os locais com maior concentração de estanho. Os resultados da primeira e segunda campanhas variaram entre 0,022 e 0,153 e entre 0,003 e 0,445µg m-3 para o ar atmosférico, enquanto para a poeira doméstica as faixas foram 0,64-1,61 e 1,97-8,54µg m-2, respectivamente. A concentração sanguínea média de estanho na população foi 385 ± 1,57µg L-1 e na urina foi 3,56 ± 1,88µg L-1. O mapa kernel mostrou as concentrações mais elevadas de estanho na poeira doméstica nos arredores ao leste da indústria. Na primeira amostragem, o ar atmosférico apresentou as concentrações ao sudoeste e sudeste da fábrica. Entretanto, riscos potencialmente altos estiveram concentrados na área central, embora a direção do vento tenha sido noroeste na segunda coleta de amostras. Os maiores pontos críticos foram ao norte, sul e sudeste da indústria, mas as amostras de urina mostraram níveis moderados a altos ao oeste a ao leste. Nas amostras de sangue, a maior diferença foi a ausência de pontos críticos ao oeste da indústria. O monitoramento ambiental é necessário para melhor avaliar a exposição ao estanho.

Resumen: El uso del estaño está muy generalizado en la industria. La literatura sobre sus efectos en humanos es escasa, especialmente en lo que concierne a los valores de referencia en indicadores biológicos como sangre y orina. Igualmente, los límites ambientales también son raros. El objetivo de este estudio fue evaluar los puntos calientes de la distribución espacial de exposición ambiental al estaño, en las proximidades de una industria de aleación, en el sur del estado de Río de Janeiro, Brasil. El estudio poblacional contó con 74 adultos. La espectrometría de absorción atómica por horno de grafito halló estaño en todas las muestras. Asimismo, las residencias se georreferenciaron con puntos alrededor de la industria mediante GPS para identificar los lugares con mayor intensidad de estaño. Los resultados de la primera y segunda campaña oscilaron de 0,022 a 0,153 y 0,003 a 0,445µg m-3 en aire atmosférico, aunque tales rangos fueron de 0,64 a 1,61 y de 1,97 a 8,54µg m-2 en el caso de polvo doméstico, respectivamente. El promedio de concentración de estaño encontrado en la sangre de la población fue 3.85 ± 1.57µg L-1. Respecto a la orina, este valor fue 3.56 ± 1.88µg L-1. El mapa de kernel expuso que las concentraciones espaciales más altas de estaño en el polvo doméstico de las casas se encontraron en la región oriental de la industria. En la primera muestra, las muestras de aire atmosférico presentaron las concentraciones más elevadas en el suroeste y sureste. No obstante, los riesgos potencialmente altos se concentraron en el área central, a pesar de que la dirección del viento era noroeste en la segunda recogida de muestras. Los puntos calientes más grandes estuvieron en el norte, sur, y sureste. Sin embargo, las muestras de orina mostraron niveles de medios a altos en el oeste y este. Respecto a las muestras de sangre, la diferencia más grande fue la ausencia de áreas calientes en el oeste. El monitoreo ambiental se hace necesario para evaluar mejor la exposición al estaño.

Efeito anti-erosivo de soluções contendo diferentes polímeros / Anti-erosive effect of solutions containing different polymers

O desgaste erosivo tem sido reconhecido como uma condição frequente nos últimos anos, principalmente devido a mudanças nos hábitos alimentares e comportamentais das populações em geral. Considerando a natureza irreversível desta condição, o diagnóstico precoce e a adoção de medidas preventivas são muito importantes. Dentre elas, a adição de polímeros a produtos de higiene bucal associados ou não a fluoretos apresenta-se como uma alternativa promissora, já que alguns polímeros apresentam compatibilidade com as estruturas dentais e capacidade de formação de um filme protetor. Este estudo foi subdivido em três artigos que visaram, através de diferentes abordagens, investigar o efeito anti- erosivo de polímeros formadores de filme, bem como o efeito da associação destes com fluoretos. O primeiro artigo consistiu em uma revisão da literatura sobre aspectos relacionados ao potencial de utilização dos polímeros para a prevenção da erosão dental. O segundo artigo consistiu em um estudo de varredura para verificar a capacidade de redução da dissolução da hidroxiapatita promovida por soluções contendo quatro polímeros (polioxirano, hidroxipropilmetilcelulose, pectina e um copolímero do polimetacrilato) associadas ou não com fluoreto de sódio -F (225 ppm F- ) e fluoreto de sódio + cloreto de estanho (800 ppm Sn2+) - FS. A mensuração do potencial zeta da hidroxiapatita dispersa tratada com as soluções experimentais foi realizada a fim de complementar a análise. O terceiro artigo consistiu em um estudo de ciclagem erosiva/reendurecedora na presença de película adquirida que se propôs a investigar o potencial de remineralização, potencial de proteção, a perda superficial e a tensão superficial do esmalte após o tratamento com as soluções contendo o copolímero do polimetacrilato. Concluiu- se que a utilização de polímeros formadores de filme, associados ou não a fluoretos, constitui uma abordagem promissora para prevenção da erosão dental. Dentre os polímeros investigados, o copolímero do polimetacrilato é um promissor agente para ser adicionado à produtos de higiene bucal visando a prevenção dos desgastes erosivos(AU)

Erosive wear has been recognized as a frequent condition in recent years, mainly due to changes in the dietary and behavioral habits of the general population. Considering the irreversible nature of this condition, early diagnosis and the adoption of preventive measures are very important. Among them, the addition of polymers to oral care products associated or not with fluorides is a promising alternative, as some polymers have compatibility with dental structures and ability to form a protective film. This study was subdivided into three articles that aimed, through different approaches, to investigate the anti-erosive effect of film- forming polymers, as well as the effect of their association with fluorides. The first article consisted of a literature review about aspects related to the potential use of polymers to prevent dental erosion. The second article consisted of a scanning study to verify the ability to decrease the hydroxyapatite dissolution promoted by solutions containing four polymers (polyoxyrane, hydroxypropyl methylcellulose, pectin and a polymethacrylate copolymer) associated or not with sodium fluoride -F (225 ppm F- ) and sodium fluoride + tin chloride (800 ppm Sn2+ ) -FS. Measurement of the zeta potential of dispersed hydroxyapatite treated with experimental solutions was performed to complement the analysis. The third article consisted of an erosive/rehardening cycling study in the presence of acquired pellicle that aimed to investigate remineralization potential, protection potential, surface loss and surface tension of the enamel after treatment with solutions containing the polymethacrylate. It was concluded that the use of film- forming polymers, associated or not with fluorides, is a promising approach for the prevention of dental erosion. Among the polymers investigated, the polymethacrylate copolymer is a promising agent to be added to oral hygiene products to prevent erosive wear(AU)

Multielemental Determination of As, Bi, Ge, Sb, and Sn in Agricultural Samples Using Hydride Generation Coupled to Microwave-Induced Plasma Optical Emission Spectrometry.

A microwave-induced plasma optical emission spectrometer with N2-based plasma was combined with a multimode sample introduction system (MSIS) for hydride generation (HG) and multielemental determination of As, Bi, Ge, Sb, and Sn in samples of forage, bovine liver, powdered milk, agricultural gypsum, rice, and mineral fertilizer, using a single condition of prereduction and reduction. The accuracy of the developed analytical method was evaluated using certified reference materials of water and mineral fertilizer, and recoveries ranged from 95 to 106%. Addition and recovery experiments were carried out, and the recoveries varied from 85 to 117% for all samples evaluated. The limits of detection for As, Bi, Ge, Sb, and Sn were 0.46, 0.09, 0.19, 0.46, and 5.2 µg/L, respectively, for liquid samples, and 0.18, 0.04, 0.08, 0.19, and 2.1 mg/kg, respectively, for solid samples. The method proposed offers a simple, fast, multielemental, and robust alternative for successful determination of all five analytes in agricultural samples with low operational cost without compromising analytical performance.