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.

Leptin-mediated ERK Signaling Pathway Promotes the Transformation of Rat Alveolar Type II Epithelial Cells Induced by Yunnan Tin Mine Dust / 中国肺癌杂志

BACKGROUND@#Currently, a significant number of miners are involved in mining operations at the Gejiu tin mine in Yunnan. This occupational setting is associated with exposure to dust particles, heavy metals, polycyclic aromatic hydrocarbons, and radioactive radon, thereby significantly elevating the risk of lung cancer. This study aims to investigate the involvement of leptin-mediated extracellular regulated protein kinase (ERK) signaling pathway in the malignant transformation of rat alveolar type II epithelial cells induced by Yunnan tin mine dust.@*METHODS@#Immortalized rat alveolar cells type II (RLE-6TN) cells were infected with Yunnan tin mine dust at a concentration of 200 μg/mL for nine consecutive generations to establish the infected cell model, which was named R₂₀₀ cells. The cells were cultured normally, named as R cells. The expression of leptin receptor in both cell groups was detected using the Western blot method. The optimal concentration of leptin and mitogen-activated protein kinase kinase (MEK) inhibitor (U0126) on R₂₀₀ cells was determined using the MTT method. Starting from the 20th generation, the cells in the R group were co-cultured with leptin, while the cells in the R₂₀₀ group were co-cultured with the MEK inhibitor U0126. The morphological alterations of the cells in each group were visualized utilizing hematoxylin-eosin staining. Additionally, concanavalin A (ConA) was utilized to detect any morphological differences, and an anchorage-independent growth assay was conducted to assess the malignant transformation of the cells. The changes in the ERK signaling pathway in epithelial cells after the action of leptin were detected using the Western blot method.@*RESULTS@#Both the cells in the R group and R₂₀₀ group express leptin receptor OB-R. Compared to the R₂₀₀ group, the concentration of leptin at 100 ng/mL shows the most significant pro-proliferation effect. The proliferation of R₂₀₀ cells infected with the virus is inhibited by 30 μmol/L U0126, and a statistically significant divergence was seen when compared to the control group (P<0.05). Starting from the 25th generation, the cell morphology of the leptin-induced R₂₀₀ group (R₂₀₀L group) underwent changes, leading to malignant transformation observed at the 30th generation. The characteristics of malignant transformation became evident by the 40th generation in the R₂₀₀L group. In contrast, the other groups showed agglutination of P40 cells, and the speed of cell aggregation increased with an increase in ConA concentration. Notably, the R₂₀₀L group exhibited faster cell aggregation compared to the U0126-induced R₂₀₀ (R₂₀₀LU) group. Additionally, the cells in the R₂₀₀L group were capable of forming clones starting from P30, with a colony formation rate of 2.25‰±0.5‰. However, no clonal colonies were observed in the R₂₀₀LU group and R₂₀₀ group. The expression of phosphorylated extracellular signal-regulated kinase (pERK) was enhanced in cells of the R₂₀₀L group. However, when the cells in the R₂₀₀L group were treated with U0126, a blocking agent, the phosphorylation level of pERK decreased.@*CONCLUSIONS@#Leptin can promote the malignant transformation of lung epithelial cells infected by mine dust, and the ERK signaling pathway may be necessary for the transformation of alveolar type II epithelial cells induced by Yunnan tin mine dust.

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.

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.

Bleaching of stained resin using nitrogen doped-TiO₂ nanoparticles / 대한치과재료학회지

There has been increasing use of the H₂O₂-based teeth bleaching agents. The purpose of this study was to evaluate the bleaching effectiveness of the laser irradiation combined with nitrogen doped-TiO₂ nanoparticles (NPs) on the stained resin. Nitrogen (N) doped-TiO₂ NPs were prepared under sol-gel method. Light absorbance, X-ray diffraction patterns of NPs, and bleaching of methylene blue and stained resins were evaluated. For bleaching of stained resin, NPs-containing gel was used. For irradiation, light of two different wavelengths was used. Unlike TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂, which have used TiN as a precursor, showed a new rutile phase at the TiN structure. For methylene blue solution, N-TiO₂ with 3% H₂O₂ resulted in the greatest absorbance decrease after laser irradiation regardless of wavelength. For stained resin test, N-TiO₂ with 3% H₂O₂ resulted in the greatest color difference after laser irradiation, followed by group that used N-TiO₂ without 3% H₂O₂.

A case of treatment-induced neuropathy in an adolescent with type 1 diabetes

Treatment-induced neuropathy (TIN) in diabetes is an acute and painful yet completely reversible small fiber neuropathy precipitated by a rapid improvement in glycemic control. TIN is rare in children. A 16-year-old girl developed symmetrical painful neuropathy of the foot, autonomic neuropathy, and retinopathy 5 weeks after the diagnosis of type 1 diabetes. All causative workups were negative except for a drop-in hemoglobin A(1c) (HbA(1c)) from 17.4% to 7%, which fit with a diagnosis of TIN. Following symptomatic management, her neuropathy and retinopathy completely resolved in 2 months. Currently, she is 18 years old and doing well (HbA(1c), 7.4%) without any recurrence of TIN. TIN should be suspected in any child presenting with recent-onset type 1 diabetes and acute onset neuropathy. Our case represents an unreported scenario of the rapid progression in TIN. Awareness among clinicians about this rare but completely reversible condition is necessary to ensure proper management and adherence to glycemic control.

Cervical Spine CT Using Spectral Shaping: Can It Be a Solution to Overcome Artifacts in the Lower Cervical Spinal Region?

OBJECTIVE: To investigate the image quality, radiation dose, and intermodality agreement of cervical spine CT using spectral shaping at 140 kVp by a tin filter (Sn140-kVp) in comparison with those of conventional CT at 120 kVp. MATERIALS AND METHODS: Patients who had undergone cervical spine CT with Sn140-kVp (n = 58) and conventional 120 kVp (n = 49) were included. Qualitative image quality was analyzed using a 5-point Likert scale. Quantitative image quality was assessed by measuring the noise and attenuation within the central spinal canals at C3/4, C6/7, and C7/T1 levels. Radiation doses received by patients were estimated. The intermodality agreement for disc morphology between CT and MRI was assessed at C3/4, C5/6, C6/7, and C7/T1 levels in 75 patients who had undergone cervical spine MRI as well as CT. RESULTS: Qualitative image quality was significantly superior in Sn140-kVp scans than in the conventional scans (p < 0.001). At C7/T1 level, the noise was significantly lower and the decrease in attenuation was significantly less in Sn140-kVp scans, than in the conventional scans (p < 0.001). Radiation doses were significantly reduced in Sn140-kVp scans by 50% (effective dose: 1.0 ± 0.1 mSv vs. 2.0 ± 0.4 mSv; p < 0.001). Intermodality agreement in the lower cervical spine region tended to be better in Sn140-kVp acquisitions than in the conventional acquisitions. CONCLUSION: Cervical spine CT using Sn140-kVp improves image quality of the lower cervical region without increasing the radiation dose. Thus, this protocol can be helpful to overcome the artifacts in the lower cervical spine CT images.

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)

Influence of scaling procedures on the integrity of titanium nitride coated CAD/CAM abutments

PURPOSE: To determine the extent of treatment traces, the roughness depth, and the quantity of titanium nitride (TiN) removed from the surface of CAD/CAM abutments after treatment with various instruments. MATERIALS AND METHODS: Twelve TiN coated CAD/CAM abutments were investigated for an in vitro study. In the test group (9), each abutment surface was subjected twice (150 g vs. 200 g pressure) to standardized treatment in a simulated prophylaxis measure with the following instruments: acrylic scaler, titanium curette, and ultrasonic scaler with steel tip. Three abutments were used as control group. Average surface roughness (Sa) and developed interfacial area ratio (Sdr) of treated and untreated surfaces were measured with a profilometer. The extent of treatment traces were analyzed by scanning electron microscopy. RESULTS: Manipulation with ultrasonic scalers resulted in a significant increase of average surface roughness (Sa, P < .05) and developed interfacial area ratio (Sdr, P < .018). Variable contact pressure did not yield any statistically significant difference on Sa-values for all instruments (P=.8). Ultrasonic treatment resulted in pronounced surface traces and partially detachment of the TiN coating. While titanium curettes caused predominantly moderate treatment traces, no traces or detectable substance removal has been determined after manipulation with acrylic curettes. CONCLUSION: Inappropriate instruments during regular plaque control may have an adverse effect on the integrity of the TiN coating of CAD/CAM abutments. To prevent defects and an increased surface roughness at the transmucosal zone of TiN abutments, only acrylic scaling instruments can be recommended for regular maintenance care.

Clinical Course of Neutropenia in Previously Healthy Children / 임상소아혈액종양

BACKGROUND: Neutropenia can be easily found in previously healthy children associated with various medical conditions, and the clinical course ranges from transient benign to life threatening. This study aimed to investigate the etiology, clinical characteristics, and clinical courses of neutropenia in previously healthy children. METHODS: We evaluated 215 previously healthy children under aged 18 years who diagnosed with neutropenia in two hospitals. Clinical and laboratory features were analyzed retrospectively based on the medical records. RESULTS: Transient infectious neutropenia (TIN) accounted for 97.7% of cases and chronic neutropenia (CN), for 2.3%. An infectious agent was identified in 128/210 (61%) patients with TIN, and the most frequent agents were viruses (46.5%). The most common viral agent was respiratory syncytial virus (RSV) (29%). TIN subgroups exhibited no differences in severity according to infectious agent (virus, bacteria, Mycoplasma); however, neutropenia severity differed among viral agents [mild-to-moderate neutropenia in the RSV group (857.3±293.3/µL) and moderate-to-severe neutropenia in the parainfluenza group (567.3±198.1/µL); P=0.017]. All patients with CN had anti-neutrophil antibody positivity (autoimmune neutropenia, AIN), and moderate-to-severe neutropenia predominated. The median duration of TIN was 8 days (range, 3–286 days), and it was significantly longer for AIN at 330 days (range, 217–730 days) (P=0.000). The median duration of neutropenia was also different according to each viral agent, with 4 days (range, 3–11 days) for the RSV group and longer durations for 3 other groups (influenza, parainfluenza, other respiratory viruses) (P=0.015). CONCLUSION: Neutropenia in previously healthy children is usually of transient infectious origin, with mild-to-moderate severity, and it resolves spontaneously without complications.

Inhibitory Effect of Metal Surface on the Antimicrobial Resistance Microorganism / 대한임상미생물학회지

BACKGROUND: The aim of this study was to comparatively evaluate the bactericidal effects of copper, brass (copper 78%, tin 22%), and stainless steel against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VREFM), and multidrug-resistant Pseudomonas aeruginosa (MRPA). METHODS: The isolates (MRSA, VREFM, MRPA) used in this study were mixed wild type 3 strains isolated from patients treated at Uijeongbu St. Mary's Hospital in 2017. These strains showed patterns of multidrug resistance. The lyophilized strains were inoculated into and incubated for 24 hr in tryptic soy broth at 35℃. The initial bacterial inoculum concentration was adjusted to 105 CFU/mL. A 100-mL bacterial suspension was incubated in containers made of brass (copper 78%, tin 22%), copper (above 99% purity), and stainless steel at 35℃. Viable counts of bacteria strains were measured for 9 days. RESULTS: In this study, the bactericidal effects of copper and brass on MRSA, VREFM, and MRPA were verified. The bactericidal effect of stainless steel was much weaker than those of copper and brass. The bactericidal effect was stronger on MRPA than on MRSA or VREFM. CONCLUSION: To prevent cross infection of multidrug resistant bacteria in hospitals, further studies of longer duration are needed for testing of copper materials on objects such as door knobs, faucets, and bed rails.

Overview of IgG4-Related Tubulointerstitial Nephritis and Its Mimickers

Tubulointerstitial nephritis (TIN) is the most common form of renal involvement in IgG4-related disease. It is characterized by a dominant infiltrate of IgG4-positive plasma cells in the interstitium and storiform fibrosis. Demonstration of IgG4-positive plasma cells is essential for diagnosis, but the number of IgG4-positive cells and the ratio of IgG4-positive/IgG-positive plasma cells may vary from case to case and depending on the methods of tissue sampling even in the same case. IgG4-positive plasma cells can be seen in TIN associated with systemic lupus erythematosus, Sjogren syndrome, or anti-neutrophil cytoplasmic antibody-associated vasculitis, which further add diagnostic confusion and difficulties. To have a more clear view of IgG4-TIN and to delineate differential points from other TIN with IgG4-positive plasma cell infiltrates, clinical and histological features of IgG4-TIN and its mimickers were reviewed. In the rear part, cases suggesting overlap of IgG4-TIN and its mimickers and glomerulonephritis associated with IgG4-TIN were briefly described.

Estudio centellográfico del vaciamiento gástrico con estaño coloidal / Scintigraphic study of colloidal tin gastric emptying

INTRODUCCIÓN: la gastroparesia se define como un retardo en el vaciamiento gástrico, en ausencia de obstrucción mecánica, asociado a síntomas como náusea y/o vómitos, sensación de plenitud gástrica posprandial, saciedad precoz o dolor epigástrico por más de 3 meses. Las causas que más frecuentemente se relacionan son la diabetes mellitus y la idiopática. La prueba de oro en el diagnóstico del retardo del vaciamiento gástrico es la gammagrafía y el radiofármaco que más se ha utilizado el 99mTc-sulfuro coloidal. OBJETIVO: evaluar el vaciamiento gástrico y mostrar los resultados obtenidos con el uso del estaño coloidal en el estudio centellográfico del vaciamiento gástrico. MÉTODOS: se realizó un estudio descriptivo en 64 pacientes de más de 18 años utilizando como radiofármaco 99mTc-Sn coloidal. RESULTADOS: el 31 % del total de pacientes presentó síntomas. El tiempo de vaciamiento fue normal en 44 casos y la asociación de síntomas y gastroparesia se observó en 20 (15 diabéticos y 5 no diabéticos), 9 pacientes tuvieron un vaciamiento retardado, pero no referían síntomas. La gastroparesia fue más frecuente en mujeres que en hombres (35 % versus 21 %). El 21 % de los casos tenían un retardo moderado del vaciamiento gástrico. CONCLUSIONES: los resultados obtenidos con 99mTc-Sn coloidal son comparables con los reportados por otros autores que utilizan el 99mTc-SC en la evaluación gammagráfica del vaciamiento gástrico.

INTRODUCTION: gastroparesis is defined as a delay in gastric emptying in the absence of mechanical obstruction, associated with symptoms such as nausea and/or vomiting, postprandial gastric fullness feeling, early satiety or epigastric pain for more than 3 months. Diabetes mellitus and idiopathic are the most frequent causes related. The gold standard in the diagnosis of delayed gastric emptying is gammagraphy and 99mTc-sulfur colloid is the most widely used radiopharmaceutical. OBJECTIVE: assess gastric emptying and show the results obtained with the use of colloidal tin in the gammagraphy study of gastric emptying. METHODS: a descriptive study was conducted in 64 patients older than 18 years using 99mTc-sulfur colloid radiopharmaceutical. RESULTS: 31 % of patients had symptoms. The emptying time was normal in 44 cases and the association of gastroparesis symptoms was observed in 20 (15 diabetics and 5nondiabetics), 9 patients had delayed emptying, but they did not report symptoms. Gastroparesis was more frequent in women than in men (35 % versus 21 %). 21 % of patients had moderate delayed gastric emptying. CONCLUSIONS: results obtained with colloidal Tc-Sn 99m are comparable with those reported by other authors using 99mTc-SC in gammagraphy assessment of gastric emptying.

Evaluation of uncertainty for determination of tin and its compounds in air of workplace by flame atomic absorption spectrometry / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the method for uncertainty evaluation of determination of tin and its compounds in the air of workplace by flame atomic absorption spectrometry.</p><p><b>METHODS</b>The national occupational health standards, GBZ/T160.28-2004 and JJF1059-1999, were used to build a mathematical model of determination of tin and its compounds in the air of workplace and to calculate the components of uncertainty.</p><p><b>RESULTS</b>In determination of tin and its compounds in the air of workplace using flame atomic absorption spectrometry, the uncertainty for the concentration of the standard solution, atomic absorption spectrophotometer, sample digestion, parallel determination, least square fitting of the calibration curve, and sample collection was 0.436%, 0.13%, 1.07%, 1.65%, 3.05%, and 2.89%, respectively. The combined uncertainty was 9.3%.The concentration of tin in the test sample was 0.132 mg/m³, and the expanded uncertainty for the measurement was 0.012 mg/m³ (K=2).</p><p><b>CONCLUSION</b>The dominant uncertainty for determination of tin and its compounds in the air of workplace comes from least squares fitting of the calibration curve and sample collection. Quality control should be improved in the process of calibration curve fitting and sample collection.</p>

Determination of stannum in urine by graphite furnace atomic absorption spectrometry / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish the method of graphite furnace atomic absorption spectrometry for the measurement of stannum in urine with calcium nitrate as the matrix modifier.</p><p><b>METHODS</b>Graphite tube was pretreated with calcium nitrate as the matrix modifier, the urine sample was diluted with 1% nitric acid and then direct injection was performed for these samples, and graphite furnace atomic absorption spectrometry was applied for measurement.</p><p><b>RESULTS</b>The concentration of stannum in urine showed a good linear relationship within the range of 8.0~40.0 μg/L, with a correlation coefficient of 0.9981. The minimum detectable concentration was 0.72 μg/L, the degree of precision was 1.54%~6.69%, and the recovery rate was 99.23%~107.63%.</p><p><b>CONCLUSION</b>This method can determine the content of stannum in urine accurately and rapidly, with a high sensitivity and a low cost.</p>

Size Control of 99mTc-tin Colloid Using PVP and Buffer Solution for Sentinel Lymph Node Detection

Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a 99mTc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with 99mTc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid (99mTc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid (99mTc-BPTC-50) were chosen for in vitro and in vivo studies. 99mTc-BPTC-50 (100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of 99mTc-PPTC-30 decreased over time, while 99mTc-BPTC-50 increased. Therefore, 99mTc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP.

Evaluation of antibacterial activity and osteoblast-like cell viability of TiN, ZrN and (Ti(1-x)Zr(x))N coating on titanium

PURPOSE: The aim of this study was to evaluate antibacterial activity and osteoblast-like cell viability according to the ratio of titanium nitride and zirconium nitride coating on commercially pure titanium using an arc ion plating system. MATERIALS AND METHODS: Polished titanium surfaces were used as controls. Surface topography was observed by scanning electron microscopy, and surface roughness was measured using a two-dimensional contact stylus profilometer. Antibacterial activity was evaluated against Streptococcus mutans and Porphyromonas gingivalis with the colony-forming unit assay. Cell compatibility, mRNA expression, and morphology related to human osteoblast-like cells (MG-63) on the coated specimens were determined by the XTT assay and reverse transcriptase-polymerase chain reaction. RESULTS: The number of S. mutans colonies on the TiN, ZrN and (Ti(1-x)Zr(x))N coated surface decreased significantly compared to those on the non-coated titanium surface (P<0.05). CONCLUSION: The number of P. gingivalis colonies on all surfaces showed no significant differences. TiN, ZrN and (Ti(1-x)Zr(x))N coated titanium showed antibacterial activity against S. mutans related to initial biofilm formation but not P. gingivalis associated with advanced periimplantitis, and did not influence osteoblast-like cell viability.

Evaluation of antibacterial activity and osteoblast-like cell viability of TiN, ZrN and (Ti(1-x)Zr(x))N coating on titanium

PURPOSE: The aim of this study was to evaluate antibacterial activity and osteoblast-like cell viability according to the ratio of titanium nitride and zirconium nitride coating on commercially pure titanium using an arc ion plating system. MATERIALS AND METHODS: Polished titanium surfaces were used as controls. Surface topography was observed by scanning electron microscopy, and surface roughness was measured using a two-dimensional contact stylus profilometer. Antibacterial activity was evaluated against Streptococcus mutans and Porphyromonas gingivalis with the colony-forming unit assay. Cell compatibility, mRNA expression, and morphology related to human osteoblast-like cells (MG-63) on the coated specimens were determined by the XTT assay and reverse transcriptase-polymerase chain reaction. RESULTS: The number of S. mutans colonies on the TiN, ZrN and (Ti(1-x)Zr(x))N coated surface decreased significantly compared to those on the non-coated titanium surface (P<0.05). CONCLUSION: The number of P. gingivalis colonies on all surfaces showed no significant differences. TiN, ZrN and (Ti(1-x)Zr(x))N coated titanium showed antibacterial activity against S. mutans related to initial biofilm formation but not P. gingivalis associated with advanced periimplantitis, and did not influence osteoblast-like cell viability.