ABSTRACT
ABSTRACT Objective: The 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 specimens of resin composite measuring 10 mm x 2 mm were prepared. Polymerization was performed using the conventional method (40 s). Each specimen was immersed for one hour per day. Evaluations were performed at baseline as well as after three, six, nine and 12 months. Three Ra readings were taken in opposite directions at each evaluation using a roughness meter. Mean Ra values were subjected to analysis of variance (ANOVA) followed by Tukey's test (p < 0.05). Results: A significant increase in Ra was found in the specimens submitted to coffee, coca-cola(r) 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. Conclusion: Based on the present findings, coca-cola, coffee and black tea exert an influence on the surface roughness of resin composites.
RESUMO Objetivo: Avaliar 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). Métodos: Foram 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). Resultados: Um aumento significativo na Ra foi encontrada nas amostras submetidas ao café, coca-Cola(r) 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. Conclusão: Com base nos achados, coca-cola, café e chá preto exercem uma influência sobre a rugosidade superficial de resinas compostas.
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 non-aged 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.