Abstract This study was aimed at analyzing the surface properties of a universal resin composite and evaluating the effect of preheating on its physicochemical properties. Two commercial resin composites were used under two conditions: Filtek Universal Restorative (UR); UR preheated (URH); Filtek Supreme (FS) and FS preheated (FSH). The film thickness (FT) test (n = 10) was done using two glass slabs under compression. Flexural strength (FLS) and modulus (FLM) were evaluated using a three-point flexion test (n = 10). Polymerization shrinkage stress (PSS) was evaluated in a universal testing machine (n = 5). Gap width (GW) between composite and mold was measured in internally polished metallic molds (n = 10). The degree of conversion (DC) was evaluated by Fourier Transform Infrared spectroscopy (n = 3). The morphology of the filler particles was checked by scanning electron microscope (SEM) and EDX analysis. Surface gloss (SG) and surface roughness (SR) were evaluated before and after mechanical brushing (n = 10). The outcomes were submitted to 2-way ANOVA and Tukey's test (α = 0.05). Lower mean values of FT were observed for the preheated groups when compared to the non-preheated groups. URH and FSH showed higher mean values of FLS and FLM when compared with UR and FS. No differences were observed between groups in the PSS test. The GW was higher for the UR and FS groups when compared with URH and FSH. The DC was higher for preheated resin composites when compared to the non-preheated groups. The SR of the UR composite was higher than the FS after mechanical brushing, while the SG was higher for the FS groups. In conclusion, the universal resin composite tested generally presented similar physicochemical properties compared with the nanofilled resin composite and either similar or slightly inferior surface properties. The preheating improved or maintained all properties evaluated.

Resumo Neste estudo avaliou-se propriedades físico-químicas e de superfície de um compósito universal pré-aquecido e comparado a um compósito convencional. Foram utilizados dois compósitos comerciais: Filtek Universal Restorative (UR); UR pré-aquecido (URH); Filtek Supreme (FS) e FS pré-aquecido (FSH). O teste de espessura de película (EP) (n = 10) foi feito usando duas placas de vidro sob compressão. A resistência à flexão (RF) e o módulo flexural (MF) foram avaliados por meio do teste de flexão de três pontos (n = 10). A tensão de contração de polimerização (TCP) foi avaliada em uma máquina de teste universal (n = 8). A largura da fenda (LF) entre o compósito e o molde foi medida em moldes metálicos polidos internamente (n = 10). O grau de conversão (GC) foi avaliado por espectroscopia de infravermelho com transformada de Fourier (n = 3). A morfologia das partículas de carga foi observada em microscopia eletrônica de varredura (MEV) e sua composição em EDX. Brilho superficial (BS) e rugosidade superficial (RS) foram avaliados antes e após escovação mecânica (n=10). Os resultados foram submetidos à ANOVA 2-fatores e as médias comparadas pelo teste de Tukey (α = 0,05). Menores valores médios de EP foram observados para os grupos pré-aquecidos quando comparados aos grupos não pré-aquecidos. URH e FSH apresentaram maiores valores médios de RF e MF quando comparados com UR e FS. Não foram observadas diferenças entre os grupos no teste TCP. A LF foi maior para os grupos UR e FS quando comparados com URH e FSH. O GC foi maior para os compósitos pré-aquecidos quando comparados aos não pré-aquecidos. A RS do compósito UR foi maior que o FS após a escovação mecânica, enquanto o BS foi maior para os grupos FS. Em conclusão, o compósito universal testado geralmente apresentou propriedades físico-químicas semelhantes em comparação ao compósito nanoparticulado e propriedades de superfície semelhantes ou ligeiramente inferiores. O pré-aquecimento melhorou ou manteve todas as propriedades avaliadas.

Abstract This study aimed to evaluate the effect of antioxidant solutions on fracture strength and bonding performance in non-vital and bleached (38% hydrogen peroxide) teeth. One hundred and eighty dentin specimens were obtained, 60 for each test: fracture strength, hybrid layer thickness, and bond strength. The groups (n=10) were randomly composed according to post-bleaching protocol: REST - restoration, without bleaching; BL - bleaching + restoration; SA - bleaching, 10% sodium ascorbate solution, and restoration; AT - bleaching, 10% α-tocopherol solution, and restoration; CRAN - bleaching, 5% cranberry solution, and restoration; CAP - bleaching, 0.0025% capsaicin solution, and restoration. Data were analyzed with ANOVA, Kruskal-Wallis, Dunn, and Qui-Square tests (α=0.05). The highest fracture strength values were observed in REST (1508.96 ±148.15 N), without significant difference for the bleached groups (p>0.05), regardless of the antioxidant use. The hybrid layer thickness in the group that was not subjected to bleaching (REST) was significantly higher than in any other group. The bond strength in the bleached and antioxidants-treated groups (SA, AT, CRAN, CAP) has no differences with the bleached group without antioxidants (BL). Adhesive failures were predominant in the groups that did not receive the antioxidant application. In conclusion, the evaluated antioxidants did not show an effect on the fracture strength, hybrid layer thickness, or bond strength of dentin bleached after endodontic treatment. The application of 10% sodium ascorbate, 10% alpha-tocopherol, 5% cranberry, or 0.0025% capsaicin solutions is not an effective step and should not be considered for the restorative protocols after non-vital bleaching.

Resumo Este estudo teve como objetivo avaliar o efeito de soluções antioxidantes na resistência à fratura e resistência de união em dentes tratados endodonticamente e clareados (38% de peróxido de hidrogênio). Cento e oitenta espécimes de dentina foram obtidos, 60 para cada teste: resistência à fratura, espessura da camada híbrida e resistência de união. Os grupos (n=10) foram compostos aleatoriamente de acordo com o protocolo pós-clareamento: REST - restauração, sem clareamento; BL - clareamento + restauração; SA - clareamento, solução de ascorbato de sódio a 10% e restauração; AT - clareamento, solução de α-tocoferol a 10% e restauração; CRAN - clareamento, solução de cranberry a 5% e restauração; CAP - clareamento, solução de capsaicina 0,0025% e restauração. Os dados foram analisados com os testes ANOVA, Kruskal-Wallis, Dunn e Qui-Quadrado (α=0,05). Os maiores valores de resistência à fratura foram observados em REST (1508,96 ±148,15 N), sem diferença significativa para os grupos clareados (p>0,05), independente do uso de antioxidantes. A espessura da camada híbrida no grupo que não foi submetido ao clareamento (REST) foi significativamente maior do que em qualquer outro grupo. A resistência de união nos grupos clareado e tratado com antioxidantes (SA, AT, CRAN, CAP) não apresentou diferenças com o grupo branqueado sem antioxidantes (BL). As falhas adesivas foram predominantes nos grupos que não receberam a aplicação do antioxidante. Em conclusão, os antioxidantes avaliados não mostraram efeito sobre a resistência à fratura, espessura da camada híbrida ou resistência de união à dentina clareada após tratamento endodôntico. A aplicação de soluções de ascorbato de sódio 10%, alfa-tocoferol 10%, cranberry 5% ou capsaicina 0,0025% não é uma etapa eficaz e não deve ser considerada para os protocolos restauradores após clareamento não vital.

ABSTRACT: The objective of this in vitro study was to evaluate the effects of finishing protocols and oral hygiene procedures on the surface and mechanical properties of CAD/CAM ceramics. Specimens (n = 96, (15x10x2mm) of the leucite glass-ceramic (LGC) and feldspathic ceramic (FP) received mechanical polishing or glazing. Surface roughness (Ra) and microhardness (VHN) were obtained with a profilometer and a hardness tester, respectively, before and after each oral hygiene procedure (TB: toothbrushing; PB: prophylaxis with paste and rubber cup; and BJ: prophylaxis with bicarbonate jet). ANOVA, paired t and Tukey’s tests were applied (a=0.05). For both materials, only BJ affected Ra's values when mechanical polishing was performed. Moreover, no significant variations in VHN were observed only for LGC glazed with TB. Significant Ra and VHN changes in both materials were observed with BJ. Besides, BJ exhibited similar effects to TB on VHN, regardless of the material and finishing protocol used. Changes in mechanical and surface properties varied with the finishing protocol and the oral hygiene method. In general, prophylaxis with bicarbonate jet was the most harmful method for both materials and the type of finishing protocol did not have a protective effect against changes produced by oral hygiene methods.

RESUMEN: El objetivo de este estudio in vitro fue evaluar los efectos de los protocolos de acabado y los procedimientos de higiene oral sobre la superficie y las propiedades mecánicas de las cerámicas CAD/CAM. Los especímenes (n = 96, (15x10x2mm) de vitrocerámica de leucita (LGC) y cerámica feldespática (FP) recibieron pulido mecánico o glaseado. La rugosidad de la superficie (Ra) y la microdureza (VHN) se obtuvieron con un perfilómetro y un probador de dureza, respectivamente, antes y después de cada procedimiento de higiene oral (TB: cepillado dental; PB: profilaxis con pasta y vaso de hule; y BJ: profilaxis con chorro de bicarbonato). Se aplicaron ANOVA, t pareada y prueba de Tukey (a=0.05). Para ambos materiales, solo BJ afectó los valores de Ra cuando se realizó el pulido mecánico. Además, no se observaron variaciones significativas en VHN solo para LGC vidriado con TB. Se observaron cambios significativos de Ra y VHN en ambos materiales con BJ. Además, BJ exhibió efectos similares a TB en VHN, independientemente del material y protocolo de acabado utilizado Los cambios en las propiedades mecánicas y superficiales variaron con el protocolo de acabado y el método de higiene oral. En general, la profilaxis con chorro de bicarbonato fue el método más perjudicial, tanto los materiales como el tipo de protocolo de acabado no tuvieron un efecto protector frente a los cambios producidos por los métodos de higiene oral.

Resumo Este estudo in vitro avaliou o efeito anti-erosivo de um verniz experimental contendo 5% de cloreto estanoso (SnCl₂) associado a diferentes concentrações de NaF (sem NaF, 2,5% NaF ou 5,2% NaF) sobre esmalte e dentina radicular bovinos. Cem amostras foram pré-erodidas (ácido cítrico 0,3%, pH 2,6, 10 min) e randomizadas em cinco grupos (n=10 para cada substrato): Controle negativo - água milli-Q; Sem NaF - Verniz experimental sem SnCl2 e sem NaF; 2,5 NaF - Verniz experimental 5% SnCl2 associado a 2,5% NaF; 5,2 NaF: Verniz experimental 5% SnCl2 associado a 5,2% NaF e controle positivo - Verniz comercial contendo 5% NaF (Duraphat). Após a aplicação dos vernizes, os desafios erosivos e abrasivos foram realizados por cinco dias. A perda de estrutura dentária (PED) foi determinada por perfilometria óptica e a perda de cálcio (ΔCa2+) por espectroscopia de absorção atômica. A análise da dentina também foi realizada por MEV. Um teste ANOVA/Bonferroni de uma via foi realizado para analisar os dados (α=0,05). Os grupos experimentais 2,5 NaF e 5,2 NaF apresentaram maior eficácia na prevenção de PED quando comparados aos demais grupos (p<0,05), independentemente do substrato. Além disso, esses grupos apresentaram menor perda no teor de Ca2+ quando comparados aos demais grupos (p<0,05), para esmalte e dentina. A dentina apresentou maior PED e de ΔCa2+ quando comparada ao esmalte em todos os tratamentos (p<0,05). Os vernizes experimentais contendo NaF 5,2% e 2,5% apresentaram resultados promissores tanto na prevenção de PED quanto na perda de Ca2+, independente do substrato estudado.

Abstract This in vitro study evaluated the anti-erosive effect of an experimental varnish containing 5% stannous chloride (SnCl₂) associated with different concentrations of NaF (NaF-free, 2.5% NaF, or 5.2% NaF) on bovine enamel and root dentin. One hundred samples were pre-eroded (0.3% citric acid, pH 2.6, 10 min) and randomized into five groups (n=10 for each substrate): Negative control - milli-Q water; NaF-free - Experimental varnish SnCl₂-free and NaF-free; 2.5 NaF - Experimental varnish 5% SnCl₂ associated with 2.5% NaF; 5.2 NaF: Experimental varnish 5% SnCl₂ associated with 5.2% NaF and positive control - Commercial varnish containing 5% NaF (Duraphat). After the varnishes were applied, the erosive and abrasive challenges were carried out for five days. Loss of tooth structure (TSL) was determined by optical profilometry, and the loss of calcium (ΔCa2+) using atomic absorption spectroscopy. Dentin analysis was also performed by SEM. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The experimental 2.5 NaF and 5.2 NaF groups showed greater effectiveness in preventing TSL when compared to the other groups (p <0.05), regardless of the substrate. In addition, these groups showed lower loss in Ca2+ content when compared to the other groups (p <0.05), for enamel and dentin. Dentin showed greater TSL and ΔCa2+ loss when compared to enamel in all treatments (p <0.05). The 5.2% and 2.5% NaF-containing experimental varnishes showed promising results in both, the prevention of TSL and the loss of Ca2+, regardless of the substrate studied.

Abstract This study aimed to analyze the influence of socioeconomic factors on the frequency of diagnoses of oral mucosal changes and the number of hospitalized patients with oral and oropharyngeal cancer in Brazil. This cross-sectional study analyzed data from all Brazilian cities in the period 2011–2017. The frequency of diagnoses of oral mucosal changes and the number of hospitalized patients of oral and oropharyngeal cancer in Brazil were extracted from the Primary Care Information System (SIAB) and Brazilian National Cancer Institute (INCA) databases. The socioeconomic factors evaluated were the Gini coefficient of inequality, municipal Human Development Index (MHDI), inadequate basic sanitation rate, employment rate, illiteracy rate and expected years of schooling. Associated factors were examined using bivariate Spearman’s correlations and multivariate Poisson regressions, and statistically significant (p < 0.05) correlations between study variables and regression coefficients were obtained. A higher frequency of diagnoses of mucosal changes was observed in cities with a higher Gini coefficient (B = 11.614; p < 0.001), higher MHDI (B = 11.298; p < 0.001), and higher number of hospitalized patients with oral and oropharyngeal cancer (B = 0.001, p < 0.002). Cities with higher Gini coefficients (B = 8.159, p < 0.001), higher inadequate basic sanitation rates (B = 0.09, p = 0.001), lower expected years of schooling (B = -0.718, p < 0.001), and higher illiteracy rates (B = 0.191, p < 0.001) had a higher frequency of hospitalized patients with oral and oropharyngeal cancer. In conclusion, more developed cities showed a higher frequency of diagnoses of mucosal changes. Greater inequality and worse socioeconomic conditions are associated with a higher frequency of hospitalized patients with oral and oropharyngeal cancer in Brazil.

Abstract The objective of this work was to evaluate the relationship between factors associated with the COVID-19 pandemic and depression, anxiety, and stress (DAS) in dentists. Factors associated with the COVID-19 pandemic were evaluated using a questionnaire and scores of the Depression, Anxiety, and Stress Scales-21 were measured. The differences between the DAS scores based on the factors associated with the COVID-19 pandemic were tested through the successive application of multivariate analysis of variance (MANOVA, α = 0.05). After a sample size calculation, 998 participants with a mean age of 39.39 (± 11.69) years were included. The effect size indicated that changes in sleep quality (η2 = 0.161), eating habits (η2 = 0.057), and physical health (η2 = 0.051) were the ones that most negatively affected DAS scores. The highest DAS scores were observed in professionals who lived with someone at high-risk for COVID-19 (p < 0.001) and in those who did not engage in leisure activities during the pandemic (p < 0.001). Dentists who worked on the frontline against COVID-19 had higher scores of anxiety and stress (p = 0.029). The highest scores for anxiety, depression, and/or stress were seen in dentists living with someone at high-risk for COVID-19, who acts on the frontline, who does not practice in leisure activities during the pandemic, who completely changed eating habits, quality of sleep and physical health during the pandemic. In general, DAS levels of dentists were associated with factors related to the COVID-19 pandemic.

ABSTRACT: The objective of the study was to evaluate marginal adaptation of Class II mesial-occlusal-distal (MOD) restorations before and after thermo-mechanical loading and volumetric shrinkage of the bulk-fill vs conventional composite resin. For marginal adaptation assessment, 24 Class II MOD cavities with cervical margins extending 1.0 mm below (distal) and 1.0 mm beyond (mesial) the cement-enamel junction were prepared in extracted human molars. The teeth were filled as follows: Group A - bulk-fill with SureFil SDR flow (first increment, 4 mm; second increment, 2 mm); Group B - bulk-fill with SureFil SDR flow as a base (first increment, 4 mm) and covered with the conventional nanohybrid composite Esthet-X HD (second increment, 2 mm); and Group C - incrementally filled with Esthet-X HD. Marginal adaptation was evaluated by scanning electron microscopy before and after thermomechanical loading (240,000 loading cycles and simultaneous 600 thermal cycles). To evaluate volumetric polymerization shrinkage, a semi-spherical mold was filled with the tested composites and placed in an AccuVol device after light curing. Both before and after loading, marginal adaptation in cervical dentin was superior (p < 0.05) for Groups A and B compared with Group C. In cervical enamel, Group B showed better marginal adaptation than Group C, and Group A presented intermediary results, between Groups B and C. Furthermore, bulk-fill flow resulted in greater shrinkage than Esthet-X HD. A significant improvement of marginal adaptation was observed when bulkfill flow was used instead of conventional composite resin both before and after thermomechanical loading. However, the bulk-fill flow presented higher volumetric polymerization shrinkage than the conventional composite.

RESUMEN: El objetivo de este trabajo consistió en evaluar la adaptación marginal de las restauraciones mesiales-oclusales-distales (MOD) de Clase II antes y después de la carga termo-mecánica y la contracción volumétrica de la carga compuesta de resina “bulk-fill” en comparación con resina convencional. Para la evaluación de adaptación, se prepararon 24 cavidades MOD de Clase II en molares humanos extraídos, los que se restauraron de la siguiente manera: Grupo A: restaurado con resina fluida Bulk-Fill SureFilSDR (primer incremento, 4 mm; segundo incremento, 2 mm); Grupo B: restaurado con resina fluida Bulk-Fill SureFil SDR (primer incremento, 4 mm) y cubierto con resina compuesta nanohíbrida Esthet-X HD (segundo incremento, 2 mm); y Grupo C - rellenado incrementalmente con Esthet-X HD. La adaptación marginal se evaluó mediante microscopía electrónica de barrido antes y después de la carga termomecánica (240.000 ciclos de carga y 600 ciclos térmicos simultáneos). Para evaluar la contracción volumétrica de la polimerización, se llenó un molde semiesférico con los compuestos probados y se colocó en un dispositivo AccuVol después del fotopolimerización. Tanto antes como después de la carga, la adaptación marginal en la dentina cervical fue superior (p <0,05) para los grupos A y B en comparación con el grupo C. En el esmalte cervical, el grupo B mostró una mejor adaptación marginal que el grupo C, y el grupo A presentó resultados intermedios, entre Grupos B y C. Se observó una mejora significativa de la adaptación marginal al utilizar la resina fluida Bulk-Fill en lugar de resina compuesta convencional tanto antes como después de la carga termomecánica. Sin embargo, la resina fluida ‘Bulk-Fill’ presentó una mayor contracción volumétrica de polimerización que el compuesto convencional.

ABSTRACT Introduction: Posts and core are frequently used in endodontically treated teeth with excessive loss of coronal tooth structure. Objective: To evaluate the effectiveness of self-adhesive cements under different pre-treatments of dentin in the resistance to extrusion of fiberglass posts. Methods: An experimental in vitro study was conducted. The randomly selected sample was 56 extracted bovine incisors with mature apices and without root curvature. Before the cementing procedure, pretreatment of dentin was performed with 11.5 % polyacrylic acid, 17 % EDTA or sodium hypochlorite. The type of failure between the post/cement/dentin was evaluated by stereomicroscope. Two hundred and sixteen bovine dentin discs were used. The disks were approximately 1 mm thick, and were obtained from 72 bovine roots restored with intraradicular retentions. Data were analyzed for better comprehension in an SPSS database for Windows version 15. Results: The highest values were found in groups G3, G4 and G5, and there was no bond strength significant difference in group G2. Conclusions: The pre-treatment had no effect on dentin bond strength, and the self-adhesive cement RelyX U100 appears to be a viable option in the cementation of fiber posts.

RESUMEN Introducción: Los postes y el núcleo se utilizan con frecuencia en los dientes tratados endodónticamente con una pérdida excesiva de la estructura dental coronal. Objetivo: Evaluar la efectividad de los cementos autoadhesivos bajo diferentes pretratamientos de dentina en la resistencia a la extrusión de postes de fibra de vidrio. Métodos: Se realizó una investigación experimental in vitro en 56 dientes de ganado seleccionados al azar con cierre apical maduro y sin curvaturas radiculares. Antes del procedimiento de cementación, se llevó a cabo el pretratamiento de la dentina con 11,5 % de ácido poliacrílico, 17 % de EDTA o hipoclorito de sodio. El estereomicroscopio evaluó el tipo de falla entre el poste / cemento / dentina. Se usaron 216 discos de dentina bovina. Los discos tenían aproximadamente 1 mm de espesor y se obtuvieron de 72 raíces bovinas restauradas con retenciones intrarradiculares. Los datos se analizaron para una mejor comprensión en una base de datos de SPSS para Windows versión 15. Resultados: Los valores más elevados fueron encontrados en los grupos G3, G4 y G5 y no fue significativa la prueba de resistencia en el grupo G2. Conclusiones: El pretratamiento no tuvo efecto sobre la fuerza de unión dentinaria, y el cemento autoadhesivo RelyX U100 parece ser una opción viable en la cementación postes de fibra.

Abstract: The aim of this study is to evaluate the machinability of four CAD/CAM materials (n = 13) assessed by brittleness index, Vickers hardness, and fracture toughness and interaction among such mechanical properties. The materials selected in this in vitro study are Feldspathic ceramic [FC], Lithium-disilicate glass ceramic [LD], leucite-reinforced glass ceramic [LR], and nanofilled resin material [RN]. Slices were made from the blocks following original dimensions 14 × 12 × 3 mm (L × W × H), using a precision slow-speed saw device and then surfaces were regularized through a polishing device. Brittleness index and fracture toughness were calculated by the use of specific equations for each one of the properties. The Vickers hardness was calculated automated software in the microhardness device. One-way Anova and Pearson's correlation were applied to data evaluation. LD obtained the highest values for brittleness index and was not significantly different from FC. LR presented statistically significant difference compared with RN, which had the lowest mean. Vickers hardness showed LD with the highest average, and no statistical difference was found between FC and LR. RN presented the lowest average. Fracture toughness showed FC and LR not statistically different from each other, likewise LD and RN. The brittleness index, considered also as the machinability of a material, showed within this study as positively dependent on Vickers hardness, which leads to conclusion that hardness of ceramics is related to its milling capacity. In addition, fracture toughness of pre-sintered ceramics is compared to polymer-based materials.

Resumo: O objetivo deste trabalho foi avaliar as perdas causadas pelas podridões da base do colmo em híbridos de milho (Zea mays), bem como identificar os principais patógenos causadores da doença, durante a safrinha, no Estado do Tocantins, Brasil. Foram realizados dois ensaios, um com cinco híbridos, em 2015, e outro com quatro, em 2016. Espigas de plantas sadias e doentes foram colhidas em cada parcela, por ocasião da colheita. Foram medidos tamanho de espigas, peso de grãos e espigas, e umidade dos grãos. De cada planta doente, foi retirado um fragmento do colmo com dois a três entrenós, utilizado para identificação e quantificação dos patógenos. Os patógenos mais comuns foram: Fusarium graminearum, Stenocarpella maydis e Macrophomina phaseolina. Todas as variáveis de produtividade foram significativamente menores nas plantas doentes, com perdas médias de 30,6%, em 2015, e de 34,3% em 2016. As maiores perdas são observadas em híbridos com maior relação entre pesos de grãos e espigas.

Abstract: The objective of this work was to assess yield losses due to stalk rot in corn (Zea mays) hybrids, as well as to identify the main pathogenic fungi responsible for the disease during the off-season, in the state of Tocantins, Brazil. Two field experiments were carried out, one with five hybrids, in 2015, and another with four, in 2016. Ears of healthy and stalk rot-infected plants were collected from each plot, at harvest. Ear size, grain and ear weights, and grain moisture content were measured. From each diseased plant, a stalk piece with two to three nodes was removed for pathogen identification and quantification. The most common pathogens were: Fusarium graminearum, Stenocarpella maydis, and Macrophomina phaseolina. All yield parameters were significantly lower in stalk rot-infected plants, with average losses of 30.6%, in 2015, and of 34.3% in 2016. The highest yield losses are observed in hybrids with the highest grain/ear weight ratio.

Resumo Introdução Os adesivos autocondicionantes apresentam técnica adesiva simplificada e diminuição na sensibilidade pós-operatória. Quando aplicados sobre a dentina, atuam sobre a smear layer, cuja efetiva remoção ainda constitui um desafio. Uma substância utilizada como pré-tratamento dentinário na ajuda da remoção da smear layer é o etilenodiamino tetracético dissódico (EDTA). Objetivo Avaliar os efeitos do EDTA em associação com sistemas adesivos autocondicionantes na resistência de união ao microcisalhamento. Material e método Foram seccionadas as superfícies oclusais de 72 terceiros molares humanos extraídos, para expor superfície dentinária plana. Os dentes preparados foram divididos em: dentina sem pré-tratamento; dentina tratada com EDTA 0,1M; dentina tratada com EDTA 0,5M. Cada grupo recebeu tratamento de três sistemas adesivos autocondicionantes: Single Bond Universal (SBU), AdheSE (AdheSE) e Clearfil SE Bond (CSEB). Foi delimitada a área adesiva e assim posicionada uma matriz transparente, para inserção com resina composta Z250XT seguida de polimerização por 40 segundos. Após 24 horas de armazenamento, os dentes foram submetidos ao ensaio de microcisalhamento. Os dados obtidos foram analisados estatisticamente, utilizando-se os testes Two-Way ANOVA e Bonferroni, e sendo considerado nível de significância de 5%. Resultado Não houve diferença estatística significante na resistência de união entre os pré-tratamentos dentinários (p=0,8353), porém houve diferença significativa entre os adesivos (p<0,05) CSEB e AdheSE, mostrando semelhança entre CSEB e SBU, e entre SBU e AdheSE. Conclusão O pré-tratamento dentinário com solução de EDTA não afetou a resistência de união com nenhum dos sistemas adesivos autocondicionantes utilizados.

Abstract Introduction Self-etching adhesives have simplified adhesive technique and decreased the postoperative sensitivity. When applied on dentin, it acts on the smear layer, but it is still a challenge in the effectiveness of this removal. A substance used as a pre-treatment for the removal of the smear layer is disodium ethylenediaminetetraacetic acid (EDTA). Objective To evaluate the effects of EDTA in association with self-etching adhesive systems on micro-shear bond strength. Material and method The occlusal surfaces of 72 extracted human third molars were sectioned to expose a flat dentin surface. The prepared teeth were divided into: dentin without pre-treatment; dentin treated with 0.1M EDTA; dentin treated with 0.5M EDTA. Each group received treatment of 3 self-etching adhesive systems: Single Bond Universal (SBU), AdheSE (AdheSE), and Clearfil SE Bond (CSEB). The adhesive area was delimited and positioned a transparent matrix for insertion with Z250XT composite resin followed by polymerization for 40 seconds. After 24h of storage, the teeth were submitted to the micro-shear test. The data were analyzed statistically using the Two-Way ANOVA and Bonferroni tests, considering a level of significance of 5%. Result There was no statistically significant difference in bond strength between dentin pre-treatments (p = 0.8353), but showed a significant difference between CSEB and AdheSE adhesives (p <0.05), showing similarity between CSEB and SBU, and between SBU and AdheSE. Conclusion Dentin pretreatment with EDTA solution did not affect bond strength with any of the self-etching adhesive systems used.

Resumo Os municípios da Amazônia brasileira são constantemente influenciados por secas e cheias, onde riscos socioeconômicos e ambientais afetam principalmente a população ribeirinha. Esses extremos de precipitação causam mudanças severas na hidrologia dos rios tanto em escala temporal quanto espacial. Sendo assim, o objetivo deste estudo foi determinar o índice do risco socioeconômico e ambiental dos municípios que recebem influência dos afluentes e da calha principal do Rio Amazonas, comparando com eventos extremos de precipitação. Utilizaram-se dados mensais e anuais de precipitação de 1982-2012 e dados sociais (população urbana, idosa, feminina e de crianças, nível de rendimento e de escolaridade) de 2010 para 47 municípios na Bacia Amazônica. Contudo, conclui-se que o risco foi maior durante eventos de cheia, principalmente, nos menores estados (Acre e Roraima) e maior vulnerabilidade nos maiores estados (Amazonas e Pará). Assim, as populações nos municípios ao longo do Rio Amazonas possuem risco socioeconômico e ambiental de moderado a muito forte devido à vulnerabilidade alta associada com a urbanização e com a pobreza, além de ameaça de enchentes e estiagens variando de moderada a alta.

Abstract Municipalities in the Amazon are constantly affected by droughts and floods, and these socioeconomic and environmental risks mainly affect the local population. These precipitation extremes cause severe changes in rivers' hydrology, on both a temporal and a spatial scale. The intended objective of this study therefore was to determine the socioeconomic and environmental risk of municipalities affected by the tributaries and by the main channel of the Amazon River in relation to extreme precipitation events. We used monthly and annual precipitation data from 1982 to 2012 and social data from 2010 (urban, elderly, female and child populations, income and education level) for 47 localities in the Amazon Basin. We concluded that the risk was highest during flood events, particularly in smaller states (Acre and Roraima), and that vulnerability was greater in larger states (Amazonas and Pará). However, the population in the municipalities along the Amazon River have moderate to very strong socioeconomic and environmental risk because of the vulnerability associated with high urbanization and poverty, and threat of floods and droughts ranging from moderate to high.

ABSTRACT: Aim: To evaluate the shear bond strength (SBS) and adhesive remnant index (ARI) of experimental brackets bonded with self-adhesive resin cement. Ninety bovine teeth were randomly distributed (n = 15) according to the groups: G1 - metal brackets bonded with Transbond™ XT; G2 - APC metal brackets bonded without additional adhesive system; G3 - APC metal brackets bonded with self-etching adhesive system; G4 - metal brackets bonded with RelyXU200; G5 - experimental brackets bonded with Transbond™ XT; G6 - experimental brackets bonded with RelyXU200. Shear bond strength test of the brackets was carried out and after their removal, the ARI was observed. Results: The highest mean value of SBS was found in group 1 (14.33 MPa) and lower mean SBS has been in group 4 (2.36 MPa). The mean values of SBS found in the experimental groups were higher compared to the non-modified brackets. The ARI analysis demonstrated that groups that received the phosphoric acid or selfetching primer (G1,G2,G3andG5) showed adhesive partially and fully adhered to the tooth. Greater amounts of remnants were adhered to the bracket in the experimental brackets, this minimizes the risk of damage to the tooth enamel since it requires minimal finishing. These results suggest that the experimental brackets are interesting options for future use in orthodontics, since it has sufficient adhesive strength to the orthodontic treatment, and less risk of damage to the enamel at the time of removal of the brackets, and is a simple and inexpensive alternative.

Resumo Introdução A evolução dos sistemas adesivos permitiu que os fabricantes desenvolvessem materiais com técnicas cada vez mais simplificadas, porém que, ainda assim, promovessem adequados valores de resistência de união imediata. Sugere-se que alguns tratamentos da superfície dentinária podem favorecer esse processo de adesão. Objetivo Avaliar os efeitos de diferentes tratamentos, em superfície dentinária plana condicionada, sobre a resistência de união à microtração de sistemas adesivos do tipo “condiciona-e-lava” de dois passos. Material e método Noventa e seis terceiros molares humanos foram divididos em 12 grupos (n=8), aleatoriamente, de acordo com o sistema adesivo utilizado (GI: Adper Single Bond 2 - 3M ESPE; GII: Prime & Bond 2.1 - Dentsply; GIII: Excite - Ivoclar Vivadent) e o tipo de tratamento do substrato dentinário condicionado (a: água; b: clorexidina + água; c: etanol; d: clorexidina + etanol). Todos os dentes foram restaurados com resina Charisma na cor A2 (Heraeus - Kulzer, Germany) e submetidos a ensaio mecânico de microtração (EMIC DL-2000). O teste estatístico realizado foi ANOVA a um fator, completado com teste de Tukey. Resultado Os grupos GIIc, GIIIc e GIId apresentaram aumento significativo estatisticamente na resistência de união à microtração imediata. Conclusão Os diferentes tratamentos da dentina condicionada não afetaram de maneira negativa a resistência de união para todos os sistemas adesivos testados e a utilização da técnica com etanol, associado ou não à clorexidina, parece ser uma interessante abordagem quando associada a sistemas adesivos “condiciona-e-lava” de dois passos.

Abstract Introduction The development of adhesive systems allow manufacturers to develop materials with increasingly simplified techniques, but that still would promote adequate resistance values of immediate union. It is suggested that some treatments of dentin surface can facilitate the process of accession. Objective To evaluate the effects of different treatments in conditioned flat dentin surface on bond strength to microtensile 2-step etch-and-rinse adhesive systems. Material and method Ninety-six human third molars were divided into twelve groups (n = 8) randomly according to the used adhesive system (GI: Single Bond 2 - 3M ESPE; GII: Prime & Bond 2.1 - Dentsply; GIII: Excite - Ivoclar Vivadent) and type of treatment of the conditioned dentin (a: water; b: water + chlorhexidine; c: ethanol; d: chlorhexidine + ethanol). All teeth were restored with Charisma color A2 (Heraeus – Kulzer, Germany) and subjected to mechanical testing microtensile (EMIC DL-2000). The statistical test performed was ANOVA 1 factor supplemented with Tukey test. Result GIIc groups GIIIc and GIId showed statistically significant increase in bond strength to immediate microtensile. Conclusion The different treatments of dentin did not affect negatively the bond strength for all tested adhesive systems and the use of the technique with ethanol, with or without chlorhexidine, appears to be an interesting approach when combined with 2-step etch-and-rinse adhesive systems.

The objective of this study was to evaluate the knowledge applied by dental students on the procedures of disinfection, tempering and pouring of irreversible hydrocolloid impressions. This study was conducted through a questionnaire to 86 undergraduate students, of both genders, of the eighth and ninth period of the School of Dentistry, Pontifical Catholic University, Belo Horizonte, MG. The questionnaire contained 12 multiple choice questions about clinical and laboratory procedures for dental impression. Analyzed data were descriptively and qualitatively. Most subjects (70%) stated they did disinfection of dental impression with 1% sodium hypochlorite spray. However, they did it in open containers (75.4%) and with time control (68.6%). The ratio water / powder is randomly conducted by most students (60.5%), and tap water is the one most commonly used (95.3%). The mixing of the calcium sulfate is done manually by nearly all students (97.7%), and use vibrator during the pouring of the calcium sulfate is common among undergraduates (60.5%). The setting of the calcium sulfate takes place predominantly exposed to air (93%) and the removal of the model is made ??between 30 and 60 min after pouring by 84.9% of students. These results point to the need for awareness of students of adopting practices transmitted during the undergraduate degree. It is also necessary to investigate the possible causes of knowledge transmission problems and how to effectively adopt good clinical practices.

El objetivo fue evaluar el conocimiento aplicado por estudiantes de odontología en los procedimientos de desinfección, templado y vaciado de las impresiones de hidrocoloides irreversibles. Este estudio se llevó a cabo a través de un cuestionario a 86 estudiantes de pregrado, de ambos sexos, del octavo y noveno período de la Escuela de Odontología de la Pontificia Universidad Católica, Belo Horizonte, MG. El cuestionario contenía 12 preguntas de opción múltiple acerca de los procedimientos clínicos y de laboratorio para impresión dental. Los datos fueron analizados de manera descriptiva y cualitativa. La mayoría de los sujetos (70%) declararon que hicieron desinfección de la impresión dental con pulverización de hipoclorito de sodio al 1%. Sin embargo, lo hicieron en recipientes abiertos (75,4%) y con un control de tiempo (68,6%). La relación agua/polvo se realizó de manera aleatoria por la mayoría de los estudiantes (60,5%), utilizando principalmente agua del grifo (95,3%). La mezcla del sulfato de calcio se realiza manualmente por casi todos los estudiantes (97,7%) y el uso del vibrador durante el vertido del sulfato de calcio es común (60,5%). El ajuste del sulfato de calcio tiene lugar predominantemente en exposición al aire (93%), la remoción del modelo se hace entre 30 y 60 min después del vaciado por un 84,9% de los estudiantes. Estos resultados apuntan a la necesidad de que los estudiantes tomen conciencia de las prácticas transmitidas durante la licenciatura. También es necesario investigar las posibles causas de los problemas de transmisión de conocimiento y cómo aplicar efectivamente las buenas prácticas clínicas.