Como as características dos LEDs de segunda e terceira geração podem influenciar a dureza de compósitos restauradores: uma revisão da literatura / How the second and third LED generation features can influence the hardness of restorative composites: a review of the literature.

Objetivo: Várias fontes de luz têm sido utilizadas desde que os materiais fotoativados foram introduzidos na odontologia. Diodos emissores de luz (LEDs) se popularizaram como a principal opção para a polimerização dos materiais restauradores. O objetivo nessa revisão da literatura foi avaliar a influência das fontes de luz emitidas por diodo (LEDs) de segunda e terceira geração sobre a dureza de compósitos restauradores. Revisão de literatura: Nas bases de dados PubMed e Google Scholar foram pré-selecionados 239 artigos na língua inglesa entre os anos de 2010 e 2020, utilizando os termos: lightcuring, LED light sources, and dental LEDs. Dos 239 artigos inicialmente selecionados, 37 artigos foram avaliados devido aos critérios de inclusão/exclusão no estudo. Considerações finais: Vários estudos apontaram diferenças importantes na dureza dos compósitos restauradores testados, tanto na superfície de topo quanto na base. No entanto, essas diferenças estavam mais associadas a características como: estado de conservação do LED, irradiância, tempo de ativação, espectro de emissão dos aparelhos e sua compatibilidade ao fotoiniciador presente no compósito. Assim, podemos considerar que o monitoramento das condições do aparelho, e a escolha correta da fonte de luz de acordo com o compósito a ser utilizado são essenciais para maximizar a dureza dos compósitos restauradores, pois embora os aparelhos de terceira geração sejam preferencialmente indicados para compósitos com fotoiniciadores alternativos, os aparelhos que emitem luz azul apresentam vantagens quando o compósito é ativado apenas pela Canforoquinona.(AU)

Objective: Several light sources have been used since the light-curing materials were introduced in dentistry. Light-emitting diodes (LEDs) have become popular as the main option for the polymerization of restorative materials. This literature review aimed to evaluate the influence of second and third generation Light-emitting Diode (LEDs) sources on the hardness of restorative composites. Literature Review: In the PubMed and Google Scholar databases, 239 scientific papers in English were pre-selected between 2010 and 2020 using light-curing, LED light sources, and dental LEDs. After reading, 37 articles were selected to compose the review. Several studies have pointed out significant differences in the hardness of the tested restorative composites, both on the top and base surfaces. However, these differences were more associated with characteristics such as: LED conservation conditions, irradiance, curing time, the emission spectrum of the devices and their compatibility with the photoinitiator used in the composite. Final Considerations: Thus, it can be considered that monitoring the condition of the device and the correct choice of light sources according to the composite to be used is essential to maximize the hardness of the restorative composites, because although third-generation devices are preferably indicated for composites with alternative photoinitiators, devices that emit blue light have advantages when the composite is activated only by Camphorquinone.(AU)

Conceitos atuais sobre a performance clínica e principais falhas do tratamento restaurador com laminados cerâmicos: uma revisão da literatura / Current status on clinical performance and main failures of laminate veneers: a review of the literature

O objetivo do presente estudo foi revisar a literatura dos últimos cinco anos e identificar os índices de sobrevivência, principais causas de falha relatadas e verificar a confiabilidade dos laminados cerâmicos como tratamento estético e funcional em longo prazo. Métodos: foi realizada uma busca ativa na Biblioteca Nacional de Medicina dos Estados Unidos (pubmed.ncbi.nlm.nih.gov), através da base de dados Medline, dos últimos cinco anos (2015-2020) na língua inglesa, utilizando os descritores: Laminate Veneers, Porcelain Laminate Veneers e Ceramic Laminate Veneers, que resultou em 35 artigos. Após a leitura dos resumos, foram excluídos 9 estudos que utilizaram laminados cerâmicos não produzidos em cerâmicas feldspáticas, ou vidro ceramizados reforçados por cristais de leucita, ou dissilicato de lítio. Foram selecionados 26 artigos categorizados como: relatos de caso, estudos clínicos, estudos in vitro e revisões de literatura. Resultados: os estudos apontaram índices de sobrevivência de 100%, após 2 anos de cimentação, até valores superiores a 80%, após 14 anos. As três principais causas de falhas apontadas foram: desadaptação de marginal (37%), pigmentação das margens (30%) e fratura ou lascamento das restaurações (3%). Considerações finais: dentro das limitações do estudo, foi possível concluir que as principais causas de falha estão associadas às margens da restauração, no entanto, os laminados cerâmicos podem atingir índices elevados de sobrevivência mesmo 14 anos após a cimentação, mostrando um alto nível de confiabilidade. (AU)

The objective of the present study was to identify the survival rate and cause of failure of ceramic laminate veneers. Methods: An active search of the last five years (2015 ­ 2020) was carried out in the United States National Library of Medicine (pubmed.ncbi.nih.gov) the MEDLINE database, in English, using the descriptors: Laminate Veneers, Porcelain Laminate Veneers and Ceramic Laminate Veneers, which resulted in 35 papers. After reading the abstracts, 9 studies that evaluated ceramic laminates that were not produced using felspathic porcelain, leucite-reinforced glass-ceramicc, or lithium disilicate glass-ceramic were excluded. Twenty-six scientific papers were selected, categorized as: Case reports, clinical studies, in vitro studies and literature reviews. Result: The studies showed survival rates between 100% after two years of cementation up to values above 80% after 14 years. The three causes of failure identified were: marginal misfit (37%), pigmentation of the margins (30%), and fracture or chipping of the restorations (3%). Final Considerations: Within the limitations of this study, it was possible to conclude that the leading causes of failure are associated with the restoration's margins. However, ceramic laminates can achieve high survival rates even 14 years after cementation, showing a high-reliability level.(AU)

Light curing resin cements containing iodonium salts promote suitable apical bonding of posts to radicular dentin

Abstract The aim of this study was to analyze the efficiency of experimental light-curing resin cements (ERCs) with a ternary photo-initiator system containing diphenyliodonium hexafluorphosphate (DPI) and different amines on retention of glass-fiber posts to dentin (GFP). ERCs formulations: a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenylpropane and triethyleneglycol dimethacrylate. Camphorquinone was used as initiator. Six experimental groups were established according to the amine used: [ethyl-4-(dimethylamino)benzoate-EDMAB or 2-(dimethylamino)ethyl methacrylate-DMAEMA] and the concentration of DPI (0, 0.5 mol%, 1 mol%). The resin cements Variolink II (dual- and light-cured versions) were used as commercial reference. Eighty recently extracted bovine incisors (n = 10) were selected for this study. The roots were prepared and the fiber posts were cemented with the resin cement specified for each experimental group. Specimens from coronal, middle, and apical thirds of the root were subjected to push-out bond strength test 24 hours after bonding. Data were subjected to split-plot ANOVA and the Tukey test (p = 0.05). ERCs containing DPI showed statistically significant higher bond strengths compared with ERCs without DPI. ERCs containing DPI were statistically similar to VARIOLINK II - dual-cured and superior to VARIOLINK II - light-cured (except for EDMAB - 1DPI in the medium third and DMAEMA - 1DPI in the coronal third). Different amines did not influence post retention. The apical root region showed the lowest bond strength for the groups EDAB-0DPI, DMAEMA-0DPI and VARIOLINK II light-cured. Light-cured ERCs containing DPI were efficient for GFP retention to radicular dentin, with similar behaviour to that of dual-curing commercial resin cement.

A influência dos ciclos políticos nos investimentos públicos em infraestrutura: um estudo nos estados brasileiros no período de 2003 a 2014 / La influencia de los ciclos políticos en la inversión pública en infraestructura: un estudio en los estados brasileños de 2003 a 2014 / The Influence of Political Cycles on Public Investments in Infrastructure: A Study of Brazilian States from 2003 to 2014

Resumo Este artigo tem como objetivo avaliar se os ciclos políticos em conjunto com viés ideológico impactam significativamente as decisões de alocação de recursos públicos em investimentos de infraestrutura nos estados brasileiros. Para atingir tal objetivo, utilizamos informações em nível estadual de 2003 a 2014 para capturar três ciclos eleitorais. Como abordagem metodológica utilizamos regressão em painel com efeitos fixos, com o objetivo de detectar características estaduais não observáveis e invariantes no tempo. Os resultados encontrados mostram a existência de influência do ciclo eleitoral se considerarmos as diferenças ideológicas interagindo com os ciclos eleitorais. Os resultados apontam que partidos de esquerda e de centro tendem a investir mais em infraestrutura em períodos pré-eleitorais se comparados com partidos de direita. Esse resultado contribui para a literatura evidenciando que ciclos podem ser mais influenciados dependendo do partido que está governando. Foi identificado adicionalmente um resultado contraintuitivo relativo ao impacto negativo nos gastos em infraestrutura quando o governador é do mesmo partido do presidente. Para essa variável, esperava-se um impacto positivo.

Resumen Este estudio tiene como objetivo evaluar si los ciclos políticos, teniendo en cuenta el sesgo ideológico de los gobiernos, tienen un impacto significativo en la toma de decisiones sobre la asignación de inversiones públicas en infraestructura en los estados de Brasil. El estudio utilizó información de los estados brasileños del período comprendido entre 2003 y 2014 para cubrir tres ciclos políticos. El método utilizado fue la regresión de efectos fijos de panel que permite identificar las características de los estados que no son claras y constantes en el tiempo. Los resultados muestran que hay influencia del ciclo electoral, si se considera que las diferencias ideológicas están vinculadas a los ciclos electorales. Los partidos de izquierda y de centro tienden a invertir más en infraestructura en los períodos preelectorales en comparación con los partidos de derecha. Este resultado también contribuye a la literatura porque muestra que los ciclos pueden ser más influenciados dependiendo del partido que gobierna. Un resultado contraintuitivo digno de mención es el impacto negativo de los gastos en infraestructura cuando el gobernador pertenece al mismo partido político que el presidente. Para esta variable, se esperaba un impacto positivo.

Abstract This study aims to evaluate whether political cycles together with the government's ideological bias have a significant impact on decision making regarding the allocation of public investments in infrastructure in the states of Brazil. This study uses information for Brazilian states for the period from 2003 and 2014 in order to cover three political cycles. It utilizes a fixed effects panel data regression which makes it possible to identify state characteristics that are unobserved and constant over time. The results show that the electoral cycle does exert an influence, if we consider that ideological differences are linked to electoral cycles. Left-wing and centrist parties tend to invest more in infrastructure in pre-election periods in comparison with right-wing parties. This result also contributes to the literature because it shows that cycles can be more influential depending on the party that is governing. A counter-intuitive result worth mentioning is the negative impact on infrastructure investment that occurs when the governor belongs to the same political party as the president. A positive impact had been expected.

Effects of different desensitizing treatments on root dentin permeability

Abstract The objective of this study was to evaluate the effects of diode laser and a desensitizing dentifrice on dentin permeability. Fifty-two root dentin fragments were obtained (5 × 5mm) and treated with 24% EDTA gel. The samples were divided into 4 groups (n = 13): G1, control (no treatment); G2, diode laser (λ = 908 nm, 1.5 W, continuous mode, 20s); G3, application of abrasive dentifrice for 1 minute (Elmex Sensitive Professional (International Gaba); and G4, application of abrasive dentifrice for 1 minute followed by irradiation with diode laser. Ten samples per group were immersed in 2% methylene blue solution for 4h. The specimens were washed, longitudinally sectioned, observed under optical microscopy, photographed and assessed based on the degree of dye leakage. The remaining samples were observed under scanning electron microscopy (SEM). The leakage data were subjected to ANOVA test, followed by Tukey's t-test (α = 5%). Groups 2, 3 and 4 showed less dye penetration than the control group (p < 0.05), but were similar among each other. SEM images showed that dentinal tubules were open in G1, and fused and occluded in G2. Group 3 showed dentinal tubules that were occluded by the metal ions from the toothpaste. G4 presented similar characteristics to G3, and the presence of fused dentin. The diode laser and the dentifrice were effective in reducing dentinal permeability, and the combination of the two treatments did not show better results than either one used alone.

Improving adhesion between luting cement and zirconia-based ceramic with an alternative surface treatment

This study evaluated the influence of an alternative surface treatment on the microshear bond strength (μsbs) of zirconia-based ceramic. Thirty-five zirconia disks were assigned to five groups according to the following treatments: Control (CO), glass and silane were not applied to the zirconia surface; G1, air blasted with 100μm glass beads + glaze + silane; G2, a gel containing 15% (by weight) glass beads applied to the ceramic surface + glaze + silane; G3, a gel containing 25% (by weight) glass beads applied to the ceramic surface + glaze + silane; and G4, a gel containing 50% (by weight) glass beads applied to the ceramic surface + glaze + silane. The specimens were built up using RelyX ARC®, according to the manufacturer’s recommendations, and inserted in an elastomeric mold with an inner diameter of 0.8 mm. The μsbs test was performed using a testing machine at a crosshead speed of 0.5 mm/min. ANOVA and Tukey’s test (p < 0.05) were applied to the bond strength values (in MPa). CO (15.6 ± 4.1) showed the lowest μsbs value. There were no statistical differences between the G1 (24.9 ± 7.4), G2 (24.9 ± 2.3), G3 (35.0 ± 10.3) and G4 (35.3 ± 6.0) experimental groups. Those groups submitted to surface treatments with higher concentrations of glass showed a lower frequency of adhesive failures. In conclusion, the glass application improved the interaction between the ceramic and the luting cement.

Effect of mouthrinses on the surface roughness of nanofilled composite / Efeito de enxaguantes bucais sobre a rugosidade de superfície de um compósito nanoparticulado

Objective: The aim of this study was to evaluate the effect of mouthrinses on the surface roughness of nanofilled restorative composite. Material and Methods: Twenty Filtek Z350 resin composit discs (4 mm in diameter and 1 mm in height) were made and roughness (μm) was measured by using profilometer with diamond measuring needle tip of 0.5 μm and accuracy of 0.01 μm. The discs were stored in distilled water at 37 °C for 24 h and randomly divided into four groups (n=5): Control – distilled water; Group 1- Plax alcohol free mouthrinse ; Group 2 –Plax Whiteningmouthrinse; Group 3 –Listerine mouthrinseand individually stored in Eppendorf tubes with distilled water at 37 °C. The specimens were maintained in distilled water during 30 days and immersed in mouthrinses every 12 h for 1 min. Elapsed the 30 days, the specimens were cleaned and storedin distilled water, inside anincubatorat 37 °C during 24 h and the surface roughness test was repeated with the same parameters previously described. The data were submitted to Two-way ANOVA. Results: No significant differences among groups were detected for the variables mouthrinse (p = 0.9038) and time (p = 0.2056), R1: Control (0.12 ± 0.04); G1 (0.13 ± 0.05); G2 (0.11 ± 0.03); G3 (0.11 ± 0.02); and R2: Control (0.16 ± 0.04); G1 (0.15 ± 0.02); G2 (0.13 ± 0.01) and G3 (0.15 ± 0.02). Conclusions: In this study the mouthrinses solutions did not promote significant changes in the surface roughness of Filtek Z350 after 30 days.

Objetivo: O objetivo nesse estudo foi avaliar o efeito de enxaguantes bucais sobre a rugosidade superfície de um compósito restaurador nanoparticulado. Material e Métodos: Vinte discos (4 mm de diâmetro e 1 mm de altura) do compósito restaurador Filtek Z350 foram confeccionados e sua rugosidade (μm) foi mensurada utilizando um rugosímetro de contato com ponta de diamante de 0,5 μm e precisão de 0,01 μm. Os discos foram armazenados em água destilada a 37 °C por 24 h, aleatoriamente divididos em quarto grupos (n=5): Controle– água destilada; Grupo 1 –EnxaguantePlaxálcool free; Grupo 2 – Enxaguante PlaxWhitening; Grupo3 – Enxaguante Listerinee armazenados individualmente em Frascos Eppendorfs com água destilada a 37°C. Durante os 30 dias de armazenamento os corpos-de-prova foram imersos nos enxaguantes bucais a cada 12 h por 1 min. Após os 30 dias os corpos-de-prova foram limpos e armazenados em água destilada a 37 °C por 24 h e as medidas de rugosidade refeitas com os mesmos parâmetros descritos anteriormente. Os dados de rugosidade foram submetidos à Análise de Variância de dois fatores. Resultados: Não foram identificadas diferenças significativas entre os grupos para as variáveis enxaguante (p=0,9038) e tempo (p=0,2056), R1: Controle (0,12 ± 0,04); Grupo1 (0,13 ± 0,05); Grupo2 (0,11 ± 0,03); Grupo3 (0,11 ± 0,02); e R2: Controle (0,16 ± 0,04); Grupo1 (0,15 ± 0,02); Grupo2 (0,13 ± 0,01) e Grupo3 (0,15 ± 0,02). Conclusões: No presente estudo, os enxaguantes bucais não promoveram alterações significativas na rugosidade de superfície do compósito Filtek Z350 após 30 dias.

Efeito de diferentes técnicas de desinfecção na precisão de moldes de alginato avaliada em modelos de gesso / Effect of different disinfection techniques on the accuracy of alginate impressions evaluated on stone casts

Objetivo: Avaliar o efeito de diferentes técnicas de desinfecção de moldes de alginato (imersão e pulverização) sobre a precisão em modelos de gessos. Métodos: A partir de um troquel mestre em formato de tronco de cone e moldeiras de PVC, foram gerados moldes de alginato (Jeltrate Dustless), e então distribuídos em cinco grupos (n = 7) de acordo com o método de desinfecção a ser realizado (controle ? sem desinfecção; HipPul pulverizado com hipoclorito de sódio; HipIm ? imersão em hipoclorito de sódio; CloPul ? pulverizado com clorexedina; CloIm ? imersão em clorexedina). Após a desinfecção, os moldes foram vazados em gesso pedra tipo III (Herodent), segundo recomendações do fabricante, e então medidos com um paquímetro digital e submetidos à análise estatística (Anova e Tukey e Krsukal-Wallise Dunn). Resultados: Todos os grupos apresentaram um determinado grau de distorção mesmo que não significativa. Entretanto, o método de imersão com hipoclorito de sódio a 1%, apresentou alteração dimensional significativamente maior quando comparado ao grupo de controle. Conclusão: A imersão em hipoclorito de sódio 1% se mostrou o método menos indicado para desinfecção dos moldes de alginato.

Photoelastic evaluation of the effect of composite formulation on polymerization shrinkage stress

We compared polymerization stress in two commercial composites and three experimental composites made using camphorquinone (CQ) and/or phenylpropanedione (PPD) as photoinitiators. The internal surfaces of photoelastic resin discs with cylindrical cavities were roughened and treated with adhesive. Composites were divided into five groups: two commercial composites (Filtek Silorane and Filtek Z250) and three experimental composites with CQ/amine, CQ/PPD/amine, and PPD/amine. Composites were photopolymerized inside cavities, and subjected to photoelastic analysis immediately and at 24 hours and 7 days later using a plane polariscope. Stress created by Silorane (3.08 ± 0.09 MPa) was similar to that of Z250 (3.19 ± 0.13 MPa) immediately after photopolymerization (p > 0.05). After 24 hours and 7 days, Z250 (3.53 ± 0.15 and 3.69 ± 0.10 MPa, respectively) showed higher stress than Silorane (3.19 ± 0.10 and 3.16 ± 0.10 MPa, respectively). Qualitative analysis immediately after photopolymerization showed composite/CQ promoted higher stress than PPD, but stress levels at other evaluated times were statistically similar, varying between 3.45 ± 0.11 MPa and 3.92 ± 0.13 MPa. At 24 hours and 7 days, Silorane created the lowest stress. All photoinitiators created comparable tensions during polymerization.

Impact of excess cement removal on vertical misfit and cement line quality in onlays / Impacto da remoção do excesso de cimento sobre desadaptação e qualidade da linha de cimento em onlays

Aim: To evaluate vertical misfit and cement line quality of onlays cemented with resin luting cements using two different methods for removal of excess cement. Materials & Methods: Lithium di-silicate restorations were fabricated and cemented at 24 human molars that received onlay type preparations. The specimens were randomly divided in two groups (n = 12): Group 1 (G1) where cement excess was removed at pre-gel stage and Group 2 (G2) with cement excess was removed after polymerization. Vertical misfits measurements at cement line were performed twice, before and after cementation. Epoxy resin replicas were obtained from the specimens and cement line quality was analyzed with a scanning electron microscope before and after the finishing and polishing procedures. The replicas were also classified according to their condition in unsatisfactory, acceptable or good. Vertical misfits values were submitted to Student test (p < 0.05) and the quality line data were analyzed with Mann-Whitney for independent samples (p < 0.05) and Wilcoxon test for paired specimens (p < 0.05). Results: Vertical misfit and cement line quality presented no difference values to G1 (26.60 ± 8.0) and G2 (24.10 ± 8.0). However, finishing and polishing procedures affect positively the cement line quality in both groups (p = 0.59). Conclusion: The cement excess removal methods had no influence on vertical misfit and cement line quality for restorations. Finishing and polishing procedures improved the cement line quality in both groups.

Objetivo: Avaliar adaptação marginal e a influência do polimento sobre a linha de cimentação de restaurações cerâmicas cimentadas com cimento resinoso utilizando duas formas dois métodos de remoção do excesso do cimento. Métodos: Foram fabricadas restaurações em cerâmica reforçada por dissilicato de Lítio e cimentadas à vinte e quatro molares humanos que receberam preparos protéticos tipo onlay. Os corpos de prova foram divididos aleatoriamente em dois grupos (n = 12): Grupo 1 (G1) em que o excesso de cimento foi removido no estágio pré-gel e Grupo 2 (G2) em que o excesso de cimento foi removido após a polimerização. A mensuração da desadaptação marginal foi realizadas em dois momentos, antes e depois da cimentação. Réplicas em resina epóxi de todos os corpos de prova foram confeccionadas para avaliação da qualidade da linha de cimentação utilizando um microscópio eletrônico de varredura antes de depois dos procedimentos de acabamento e polimento e classificado como insatisfatório, aceitável e boas condições. Os valores de desadaptação foram submetidos ao teste t de Student (p < 0,05) e os dados de qualidade da linha de cimentação foram analisados pelo teste de Mann-Whitney para amostras independentes (p < 0,05) e pelo teste de Wilcoxon para amostras pareadas (p < 0,05). Resultados: A desadaptação marginal e a qualidade da linha de cimentação não apresentaram diferença significativa G1 (26,60 ± 8,0) e G2 (24,10 ± 8,0). Entretanto, os procedimentos de acabamento e polimento influenciaram positivamente a qualidade da linha de cimentação em ambos grupos (p = 0,59). Conclusão: O método de remoção do excesso de cimento não influenciou a adaptação ou a qualidade da linha de cimentação das restaurações cerâmicas. Os procedimentos de acabamento e polimento melhoraram a qualidade da linha de cimento nos dois grupo

Avaliação do modo de ativação sobre a resistência à flexão e módulo de elasticidade de compósito restaurador com barras de diferentes formatos / Evaluation of activation modes on flexural strength and elastic modulusof a restorative composite testing bars with different shapes

Introdução e objetivo: O objetivo deste estudo foi avaliar a influência de dois modos de fotoativação sobre resistência à flexão e módulo de elasticidade de um compósito restaurador em dois formatos de barras. Materiais e método: Como controle (CO) foram confeccionadas dez barras seguindo a norma 4049/2000 da ISO (25 x 2 x 2 mm), fotoativadas em modo contínuo por 20s, e vinte barras experimentais com (comprimento x altura x largura) 7 x 1 x 2 mm foram confeccionadas e divididas em dois grupos G1 - fotoativação contínua por 20s e G2 - fotoativação por pulso tardio com ativação inicial de 2s e complementação de 18s após 5min. Após 24h da ativação, o teste foi realizado em uma máquina de ensaios com velocidade constante de 0,5 mm/min e monitorado pelo programa Blue Hill 2, que forneceu os valores de resistência à flexão (MPa) e módulo de elasticidade (GPa). Os valores foram sub-metidos à análise de variância de um fator e ao teste de Tukey (5%). Resultados: CO apresentou os maiores valores de resistência à flexão (158,6 ± 10,6) e módulo de elasticidade (12,20 ± 0,25), quando comparado a G1 (131,65 ± 21,2 e 9,28 ± 3,7) e G2 (131,1 ± 16,9 e 10,1 ± 4,4), que não apresentaram diferença significativa entre si. Conclusão: Foi possível concluir que a barra nas dimensões da ISO apresentou maiores valores de resistência à flexão e módulo de elasticidade que as barras experimentais e que os modos de ativação não influenciaram nas propriedades estudadas entre as barras experimentais.

Influence of ceramic primers on microshear bond strength between resin cements and zirconia-based ceramic

This study evaluated the effect of a coupling agent ceramic primer (CP) on the microshear bond strength (ìsbs) between luting cements and zirconia-based ceramic. Methods: Zirconia discs (Cercon) were made and finished with silicon carbide paper and submitted to air abrasion using 50 μm aluminum oxide particles (Al2O3) under 4 bar pressure. Zirconia disks were randomly assigned to four groups (n=10): (G1) ResiCem luting cement + Porcelain Primer, (G2) ResiCemluting cement only, (G3) Clearfil Esthetic Cement + Clearfil Ceramic Primer and (G4) Clearfil Esthetic Cement only. The luting cements were prepared according to manufacturers’ recommendations and inserted in an elastomeric mold positioned onto a zirconia disc. Each specimen was photoactivated by 20 s. The specimens were stored at 100% relative humidity and 37ºC for 24 h. The ìsbs test was performed using universal testing machine at a crosshead speed of 0.5 mm/min. An optical microscope was used to analyze the failure modes and illustrative images were captured with a scanning electron microscope. The ìsbs data were analyzed by two-way ANOVA (p<0.05). Results: No significant difference was found among the four groups G1 (17.4±6.8), G2 (17.1±5.5), G3 (15.6±5.5) and G4 (14.2±3.5), all of which showed 100% of adhesive failures. Conclusions: CP showed no increase in the ìsbs between zirconia-based ceramic and resin luting cements.

Teste de alelismo entre os mutantes de amadurecimento alcobaça e non-ripening em tomateiro / Allelism test between the alcobaça and non-ripening mutants in tomato plants

Desde o início da década de 1980, são relatadas na literatura divergências quanto às relações de alelismo ou não entre os mutantes de amadurecimento de frutos de tomateiro denominados alc (= alcobaça) e nor (=non-ripening). Para dirimir tais dúvidas, foi realizado um teste de alelismo entre os genes considerados. Foram avaliadas 364 plantas F2 provenientes do cruzamento entre as linhagens de tomateiro TOM-559 (alc/alc) e TOM-613 (nor/nor), além de vinte plantas de cada uma das linhagens TOM-559 (alc/alc), TOM-613 (nor/nor), de cada um dos híbridos F1 [(TOM-559 x TOM-613), alc+/alc nor+/nor], F1 [(Floradade x TOM-559), alc+/alc nor+/nor+] e F1 [(Floradade x TOM-613), alc+/alc+nor+/nor], bem como da linhagem de genótipo normal Floradade (alc+/alc+nor+/nor+ rin+/rin+). TOM-559 e TOM-613 são linhagens isogênicas à cv. Floradade, da qual diferem apenas quanto à presença dos genes alc e nor, respectivamente. Frutos de Floradade colhidos no estádio breaker apresentam coloração vermelha normal quando maduros (fenótipo normal), enquanto frutos de TOM-559 ou de TOM-613 permanecem amarelados ou amarelo-alaranjados (fenótipo mutante). De cada planta, foram colhidos quatro frutos no estádio breaker de maturação, que foram avaliadas quanto ao fenótipo (normal ou mutante) quando maduros. Os resultados dos testes de alelismo indicam que a hipótese mais provável é a de que alc e nor sejam alélicos. Dessa maneira, alc é considerado um terceiro alelo no loco nor, e sugere-se a substituição de seu símbolo para norA.

Since the early 1980's there are conflicting reports on the possible allelic relations between the tomato ripening mutants alc (=alcobaça) and nor (=non-ripening). In order to end these controversies, a test of allelism between the genes alc and nor was performed. A total of 364 plants of the F2 population between the tomato lines TOM-559 (alc/alc) and TOM-613 (nor/nor) were screened, along with 20 plants each of lines TOM-559 (alc/alc) and TOM-613 (nor/nor), of hybrids F1 [(TOM-559 x TOM-613), alc+/alc nor+/nor], F1 [(Floradade x TOM-559), alc+/alc nor+/nor+] and F1 [(Floradade x TOM-613), alc+/alc+nor+/nor], and of the normal phenotype line Floradade (alc+/alc+nor+/nor+). TOM-559 and TOM-613 are near-isogenic lines to Floradade, and differ from the latter only due to the presence of genes alc and nor, respectively. Floradade fruit harvested at the breaker stage show normal red color (normal phenotype) when fully ripe, whereas fruit of either TOM-559 or TOM-613 remain yellow or yellowish-orange (mutante phenotype). Four fruits per plant were harvested at the breaker stage and subsequently evaluated for their mature fruit color phenotype (normal or mutant). The results of the test of allelism indicate that the most likely hypothesis is that alc and nor are allelic to each other. Therefore, alc was considered to be a third allele at the nor locus, and the symbol norA was substituted for alc.

Influence of powder/liquid ratio on the radiodensity and diametral tensile strength of glass ionomer cements

Clinicians tend to make reductions in glass ionomer power/liquid (P/L) ratios since some materials are difficult to mix and flow into small cavities, grooves or pits. In general, changing the P/L ratio decreases the physical and mechanical properties of conventional glass ionomer cements (GICs) and resin modified glass ionomer cements (RMGICs), but alterations seem to depend on their composition. OBJECTIVE: To determine the influence of P/L ratio on the radiodensity and diametral tensile strength (DTS) of glass ionomer cements. MATERIAL AND METHODS: There were 2 factors under study: P/L ratio (manufacturer's recommended P/L ratio and a 50 percent reduced P/L ratio), and materials (Vitro Molar, Vitro Fil, Vitro Cem conventional GICs and Vitro Fil LC, Ortho Glass LC RMGICs. Five 1-mm-thick samples of each material-P/L ratio were produced for radiodensity evaluation. Samples were x-ray exposed onto Digora phosphor plate and radiodensity was obtained using the software Digora for Windows 2.5 Rev 0. For DTS, five (4.0x8.0 mm) cylinder samples of each material were tested (0.5 mm/min). Data were subjected to one- and two-way ANOVA (5x2) followed by Tukey's HSD test, or Kruskal-Wallis and Dunn's method. For paired comparisons, t-test or Mann-Whitney test were used (α=0.05). RESULTS: There was a significant interaction (P=0.001) for the studied factors (materials vs. P/L ratio). Reduced P/L ratio resulted in significantly lower DTS for the RMGICs, but radiodensity was affected for all materials (P<0.05). CONCLUSIONS: Reduced P/L ratio affected properties of the tested glass ionomer cements. RMGICs were more susceptible to lower values of DTS, but radiodensity decreased for all materials following P/L ratio reduction.

Radiodensity evaluation of dental impression materials in comparison to tooth structures

In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals. OBJECTIVE: The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin. MATERIAL AND METHODS: Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15), being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05). RESULTS: Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05), but not to bovine enamel (p<0.05). Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05). CONCLUSION: Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.

Luting glass ceramic restorations using a self-adhesive resin cement under different dentin conditions

OBJECTIVES: The aim of this study was to investigate the bond strength of ceramic restorations luted using a self-adhesive resin cement (RelyX Unicem, 3M ESPE) under different dentin conditions. MATERIAL AND METHODS: In the experimental groups, ceramic restorations were luted to bovine incisors with RelyX Unicem under the following conditions: [Dry dentin]: surface was dried using air stream for 15 s; [Moist dentin]: excess dentin moisture was removed with absorbent paper; [Bonding agent]: Clearfil SE Bond (Kuraray) self-etching adhesive system was previously applied to dentin. In the Control group, cementation was done using an etch-and-rinse adhesive (Excite DSC) and Variolink II resin cement (Ivoclar Vivadent). Photoactivation of the resin cements was performed with UltraLume LED 5 unit (Ultradent). The restorations (n=5 per group) were sectioned into beams and microtensile testing was carried out. Data were subjected to ANOVA and Tukey's test (p<0.05). Failure modes were classifed under Scanning Electron Microscopic (SEM) (x120 magnifcation). RESULTS: The bond strength was dependent on the moisture status of the dentin. Bond strength in the "dry dentin group" was signifcantly lower than that of all other groups, which showed similar results. A predominance of mixed failures was detected for the control group, while a predominance of adhesive failures was observed for the "bonding agent" and "dry dentin" groups. The "moist dentin" group presented predominantly cohesive failures within the luting material. The previous application of a self-etching adhesive showed no signifcant effect. CONCLUSIONS: Only excess dentin moisture should be removed for the cementation of ceramic restorations with self-adhesive resin cements.

Bonding to wet or dry deproteinized dentin: micro tensile bond strength and confocal laser micromorphology analysis

Aim: To investigate the influence of deproteinization and moisture condition (wet vs. dry) on the bond strength and micromorphology of resin-dentin bonding interfaces. Methods: Dentin surfaces were etched with 37% phosphoric acid for 15 s and rinsed with water. Four groups (n = 10) were tested: WET: dentin was left visibly moist; DRY: dentin was dried with compressed air; WET-D: dentin was deproteinized for 60 s using 10% NaOCl solution and left moist; DRY-D: dentin was deproteinized and dried. Prime&Bond 2.1 adhesive was applied and the teeth were restored with composite resin. Microtensile test was carried out after 24 h, and failure modes classified under magnification. Data were subjected to two-way ANOVAand Tukey’s test (P < 0.05). The bonding micromorphology was analyzed by confocal laser scanning microscopy. Results: The group DRY showed significantly lower bond strength (P < 0.05) than the other groups, which were similar to each other (P > 0.05). Adhesive failures were predominant. Analysis of micromorphology showed formation of a collagen-resin hybrid layer only for the non-deproteinizedgroups. Adhesive penetration into the dentinal tubules was deeper for the DRY-D compared to the WETD group. Conclusion: The bond strength was not dependent on the moisture condition and a more homogeneous hybridization was obtained when dentin was deproteinized.

Influence of sterilization method on the bond strength of caries-affected dentin

This study evaluated the effect of sterilization method on the bond strength of caries-affected dentin before artificial caries development and after restoration. Twelve bovine incisors were sectioned perpendicularly to their long axes at 7 mm from the amelodentinal junction. They were painted with acid-resistant nail varnish, except on an exposed coronal dentin area. Four groups were formed (n = 3) in accordance with the sterilization method used, before artificial caries development and after complete restoration: NE - no sterilization (control group); G - gamma-rays before and after; A - steam autoclave before and after; AG - steam autoclave before and gamma-rays after. For artificial caries development, dentin sections were immersed in BHI broth with S. mutans. After the soft carious tissue was removed, dentin was restored with Scotchbond Multi-Purpose and Filtek Z250. Next, the samples were sterilized in accordance with the methods described above and microtensile testing was performed. The data were analyzed by the Mann-Whitney test (p < 0.05). The G (22.7 MPa) and AG groups (16.3 MPa) were not statistically different from the NE group (17.5 MPa). Nevertheless, there were statistical differences between groups A (6.3 MPa) and NE, A and G, A and AG, G and AG. The bond strength of caries-affected dentin was not influenced by gamma-ray sterilization irrespective of whether the sterilization was performed before or after restoration.

Caracterização e avaliação de acilaçúcar sintético no comportamento da mosca-branca Bemisia Tabaci (Gennadius, 1886) biótipo B (Hemiptera: Aleyrodidae) em tomateiro / Characterization and evaluation of synthetic acylsugar on the behavior of the whitefly Bemisia tabaci (Gennadius, 1886) b biotype (hemiptera: aleyrodidae) in tomato plant

O cultivo de tomate é uma atividade de destaque no Brasil em termos de produção e consumo e os estados de Goiás, São Paulo e Minas Gerais são os principais produtores. Visando a desenvolver novos compostos com função inseticida, este trabalho foi desenvolvido com o objetivo de sintetizar acilaçúcares, aleloquímico presente nas folhas que conferem resistência natural ao tomateiro Lycopersicon pennellii e avaliar seus efeitos no comportamento da mosca-branca. O delineamento utilizado foi o inteiramente casualizado, com cinco tratamentos e cinco repetições. Os ensaios consistiram dos seguintes tratamentos: plantas de tomate cv. Santa Clara pulverizadas com água pura (testemunha); plantas de tomate cv. Santa Clara pulverizadas com acilaçúcar 01 (sintetizado a partir de sacarose); plantas de tomate cv. Santa Clara pulverizadas com acilaçúcar 02 (sintetizado a partir da glicose com cloreto de zinco como catalisador); plantas de tomate cv. Santa Clara pulverizadas com acilaçúcar 03 (sintetizado a partir da glicose com acetato de sódio como catalisador) e plantas de tomate Lycopersicon pennellii pulverizadas com água pura. A concentração do composto utilizada foi de 0,05 por cento. Os resultados obtidos mostraram que o acilaçúcar 03 reduz a oviposição do inseto no tomateiro. Todavia, se fazem necessários estudos mais detalhados para se avaliar melhor a ação desse composto sobre a mosca-branca.

Tomato plant growing is an important activity in Brazil both in production and in consumption, and the states of Goiás, São Paulo and Minas Gerais are the main producing states. In order to develop new products with insecticide activity, this work was developed with the aim synthesizing acylsugar, alelochemical present in the leaves that give natural resistance to the tomato plant Lycopersicon pennellii evaluating and its effects on the behavior of the whitefly. The layout used was a completely randomized design, with five treatments and five repetitions. The trials consisted of the following treatments: Santa Clara tomato plants cultivar sprayed with pure water (control); Santa Clara tomato plants cultivar sprayed with acylsugar 01 (synthesized starting from sucrose); Santa Clara plants of tomato cultivar sprayed with acylsugar 02 (synthesized starting from the glucose with chloride of zinc as catalyst); tomato plants Santa Clara cultivar sprayed with acylsugar 03 (synthesized starting from the glucose with acetate of sodium as catalyst) and tomato plants Lycopersicon pennellii splayed with pure water. The concentration of the composition used was of 0.05 percent. The results showed that the acylsugar 03 reduce the egg laying activity of the whitefly in the tomato plant. However, it seems necessary to deepen studies to evaluate the action of this product on the whitefly behavior.

Influência do tempo de fotoativação na resistência à flexão de compósitos restauradores / Influence of photoactivation time on flexural strength of restorative composites

Este estudo avaliou a influência de dois tempos de fotoativação sobre a resistência à flexão de quatro compósitos comerciais. Amostras em forma de barra (25 mm x 2 mm x 2 mm) foram confeccionadas em matriz de aço inoxidável de acordo com s ISO 4049 e fotoativadas com um aparelho LED com cinco ativações de 20 ou 60s, em diferentes pontos ao longo das superfícies de topo e base da amostra. O teste foi realizado em uma máquina de ensaios mecãnicos com velocidade de 0,05 mm/min. As médias (MPa) foram submetidas à análise de variância de dois fatores e ao teste de Tukey (p < 0,05). Em ambos os tempos de fotoativação, os compósitos Filtek Supreme® e Esthet-X® apresentaram os maiores valores de resistência à flexão. O compósito Opallis® apresentou valores intermediários com 20s de ativação, diferindo estatisticamente do compósito 4 Seasons® com a menor média. Com 60s de ativação, os compósitos Opallis® e 4 Seasons® obtiveram médias significativamente menores que os demais, mas não diferiram entre si. Todos os compósitos apresentaram aumento significativo dos valores de resistência à flexão com o aumento do tempo de ativação. Concluiu-se que a fotoativação por 60s aumentou os valores de resistência à flexão dos compósitos.