ABSTRACT
El objetivo fue analizar in vitro la resistencia de la unión al cizallamiento de sistemas adhesivos convencional y autocondicionante sobre la superficie de esmalte y dentina después del proceso erosivo ocasionado por una bebida ácida. Cuarenta incisivos bovinos fueron seccionados y desgastados hasta obtener superficies planas en esmalte y dentina. Sobre estas, fue simulado un proceso erosivo utilizando Coca-Cola® por 10 días, 4 veces al día durante 10 min. Después, las muestras fueron divididas en 4 grupos: G1-esmalte y G2-dentina, ambas superficies hibridizadas con adhesivo convencional (Adper Single Bond II); G3-esmalte y G4-dentina, hibridizados con sistema autocondicionante (Clearfil SE Bond). Cilindros de resina compuesta (Filtek Flow Z350) con 2 mm. de altura por 0,8 mm. de diámetro fueron confeccionados y almacenados en agua deionizada a 37º C por 24h. Terminado el período, fueron sometidos al test de microcizallamiento en Emic DL 2000 con una velocidad de 1mm/min. hasta la fractura. Los resultados fueron sometidos al análisis estadístico (ANOVA One-way) y las medias comparadas por el Teste post-hoc Games-Howell. Los grupos G1 y G3 presentaron los mayores valores medios (11,92 e 14,93MPa respectivamente) con diferencia estadística entre si (p<0.05). Los grupos G2 y G4 presentaron los menores valores (2,35 e 5,50MPa respectivamente) con diferencias estadísticas entre si (p<0.05). Se concluye que los sistemas adhesivos testados actuaron efectivamente sobre el esmalte después de la erosión, no siendo tan eficaz en la dentina, probablemente, debido al over etching
The aim of the present study was to verify the shear bond strength of total and self-etching systems on the surface of enamel and dentine after erosive process. 40 bovine incisors were sectioned and finished until the surfaces got planned in enamel and dentine. On these, erosive process was simulated by using Coke® for 10 days, 4 times by day during 10 min. After, the samples were divided in 4 groups: G1-enamel and G2-dentine, both surfaces were hybridized with total-etching adhesive system (Adper Single Bond II); G3-enamel and G4-dentine were hybridized with self-etching system (Clearfil SE Bond). Resin composite cylinders (Filtek Flow Z350) with 2 mm of height for 0,8 mm of diameter were constructed on these hybridized surfaces and after they were stored in distilled water at 37ºC for 24h. Subsequently, they were submitted to the microshear test in Emic DL 2000 with speed of 1mm/min until failure. The results were submitted to the statistical analysis (ANOVA One-way) and the means were compared by the Test post-hoc Games-Howell. The groups G1 and G3 presented the highest mean values (11.92 and 14.93MPa respectively) however they differed statically itself (p<0.05). By the other hand, the groups G2 and G4 showed the lowest mean values of bond strength (2.35 and 5.50MPa respectively) and they were statistically differents (p<0.05). It can be concluded that both adhesive systems acted effectively on the enamel after erosion process, but on dentin the adhesives were not so efficient due to over etching