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Effects of different surface treatments and accelerated artificial aging on the bond strength of composite resin repairs Abstract: The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs) were prepared and divided into 24 groups (n = 8). Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments were phosphoric acid + silane + adhesive (PSA); phosphoric acid + adhesive (PA); diamond bur + phosphoric acid + silane + adhesive (DPSA); diamond bur + phosphoric acid + adhesive (DPA); air abrasion + phosphoric acid + silane + adhesive (APSA); and air abrasion + phosphoric acid + adhesive (APA). The repair was performed and the specimens were again aged as described above. A control group (n = 8) was established and did not receive any type of aging or surface treatment. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Data were analyzed by one-way ANOVA/Tukey's test (p < 0.05). No statistically significant differences were found among DPSA, DPA, APSA, APA, and the control group. The aged PSA and PA achieved low bonding values and were statistically different from the control group, whereas the nonaged PSA and PA presented no statistically significant difference from the control group. Repairs with the proposed surface treatments were viable on both recent and aged restorations; however, phosphoric acid + adhesive alone were effective only on recent restorations.

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The present findings demonstrate that restorations with established and active lesions at the margins when visually inspected often require removal and retreatment.

Aim:To compare the retention of glass ionomer cement (GIC) used as fissure sealant with a resinbased sealant. Methods: Six-to nine-year-old children (n=96) with all permanent first molars in occlusion were examined and assigned to two groups: GIC sealant or resin-based sealant. The sealants were applied according to the manufacturers' recommendations. The assessment of sealant retention was performed at two-month interval sessions (n=6), when each sample was scored according to the following criteria: complete retention, partial retention or complete loss. The visual and tactile examinations were carried out with a WHO probe, mouth mirror, air syringe and artificial light. The data were submitted to descriptive statistics and survival analysis. Results: A total of 384 occlusal surfaces were analyzed. Independent of the tooth and evaluation time, slightly better results were achieved by the resin-based sealant, but the difference was not statistically significant. Conclusions: GIC and resin-based sealants achieved similar results with regards to retention during a one-year follow-up period.

Aim:The aim of this in vitro study was to evaluate the flexural strength of a composite resin polymerized with three different modes of light exposure.Materials and Methods:The three different modes of light exposure were conventional, 600 mW/cm2/40s; soft start, 300 mW/cm2/10s + 600 mW/cm2/30s; pulse delay, 600 mW/cm2/1s + 60 s of waiting time + 600 mW/cm2/39s). Twenty samples were prepared for each polymerization method. Flexural strength (FS) tests were carried out with a 2 kN load at a speed of 0.5 mm/ min. All tested groups were submitted to analysis of variance (one-way-ANOVA) and Tukey's test (P < 0.05).Results:When stored in water, conventional and pulse delay groups presented higher FS values which were statistically different from the soft start group. When stored in 100% ethanol, conventional and soft start groups presented higher FS values which were statistically different from the pulse delay group.Conclusion:Different polymerization modes and immersion media can affect the physical properties (flexural strength) of composite resin.

ObjectiveThe aim of the present study was to evaluate the surface roughness (Ra) of the Z-350 resin composite following immersion in different media (distilled water, coca-cola, coffee, black tea and red wine). Methods Fifty Results A significant increase in Ra was found in the specimens submitted to coffee, coca-cola ® and black tea between baseline and the three-month evaluation. Variance was also found among the remaining evaluation times (3 months to 12 months), but the differences did not achieve statistical significance. No statistically significant differences in Ra were found among evaluation times in the specimens submitted to red wine or distilled water. ConclusionBased on the present findings, coca-cola, coffee and black tea exert an influence on the surface roughness of resin composites. RESUMO ObjetivoAvaliar a rugosidade da superfície (Ra) do Z-350 resina composta após imersão em diferentes meios (água destilada, coca-cola, café, chá preto e vinho tinto). MétodosForam preparados cinquenta espécimes de resina composta medindo 10 mm x 2 mm. A polimerização foi realizada através do método convencional (40 s). Cada espécime foi imerso durante uma hora por dia. As avaliações foram realizadas na linha de base, bem como após três, seis, nove e 12 meses. Três leituras Ra foram levados em direções opostas em cada avaliação, utilizando um medidor de rugosidade. Os valores médios de Ra foram submetidos a análise de variância (ANOVA) seguido pelo teste de Tukey (p <0,05). ResultadosUm aumento significativo na Ra foi encontrada nas amostras submetidas ao café, coca-Cola ® e chá preto entre o início e a avaliação de três meses. Variância também foi encontrado entre as épocas de avaliação restantes (3 meses a 12 meses), mas as diferenças não atingiram significância estatística. Não houve diferenças estatisticamente significativas na Ra encontrados entre os momentos de avaliação nos casos submetidos ao vinho tinto ou água destilada. ConclusãoCom base nos achados, coca-cola, café e chá preto exercem uma influência sobre a rugosidade superficial de resinas compostas.Termos de indexação: Bebidas. Imersão. Resinas compostas. Erosão dentária.

Posteriormente ao clareamento dental, pode haver a necessidade da troca de restaurações, utilizando procedimentos estético-adesivos. Objetivou-se avaliar a resistência adesiva de resina composta em esmalte de dentes clareados (DC) e dentes não clareados (DNC) em função de três sistemas adesivos. Utilizou-se o clareador Whiteness Perfect 10% (FGM), a resina Filtek Z-350 e os sistemas adesivos Adper Scotchbond Multi Pourpose, Adper Single Bond 2 e Adper Easy One (3M ESPE). Criou-se 6 grupos (n=10), sendo: G1=DNC+Adper Scotchbond Multi Pourpose; G2=DC+Adper Scotchbond Multi Pourpose; G3=DNC+Adper Single Bond 2; G4=DC+Adper Single Bond 2; G5=DNC+Adper Easy One; e G6=DC+Adper Easy One. Selecionou-se 30 molares cortados (MD) em cortadeira ISOMET 1000 (Buehler) e embutidos em anéis de PVC. As superfícies de esmalte foram planificadas em politriz metalográfica (TECLAGO). Os corpos de prova foram clareados por 2 horas diárias por 14 dias e armazenados sob umidade relativa de 100% a 37±2 o C. Após 24h, os protocolos adesivos foram realizados e uma matriz de silicone (2mm diâmetro/altura) foi justaposta ao corpo de prova para inserir a resina. Fotopolimerizou-se com Elipar FreeLight 2 (3M ESPE) por 40 segundos. Submeteu-se os corpos de prova ao cisalhamento na máquina EMIC DL 2000, com célula de carga de 200 Kgf e velocidade do atuador de 0,5mm/min. Aos resultados (MPa), aplicou-se análise de variância ANOVA e teste de Tukey (p<0,05): G3(11,3±1,18) > G1(5,5±1,39) = G5(4,5±0,92) e G4(16,5±1,21) > G2(7,2±1,45) = G6(6,0±1,02). Concluiu-se que para DC e DNC os sistemas adesivos mostraram comportamentos estatisticamente semelhantes; e o sistema adesivo Adper Single Bond 2 apresentou a maior resistência adesiva em esmalte.