Effect of self-etching adhesives on intact and ground enamel / Efeito de sistemas adesivos sobre a superficie do esmalte dental integro e desgastado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The aim of this study was to evaluate the effect of the self-etching systems Prompt L-Pop (PLP-ESPE), Adper Prompt (AD-3M/ESPE) e Clearfil SE Bond (SE-Kuraray) on ground (G) and unground (U) enamel in comparison to the total-etch system Single Bond (SB-3M/ESPE). Fifty-two non-carious human third molars were used in this study. Thirty-two teeth were separated in 4 Groups of 8 teeth to analyze the etching pattern and the resin-enamel interface. On Group 1 (n=3) a 35% phosphoric acid was applied, on Group 2 (n=3) the SE primer, and on the Groups 3 (n=3) and 4 (n=3) the ?all in one? adhesives systems PLP and AD, respectively. The bonding procedures were performed on the five remainders teeth of each Group with the application of the bonding resins (Groups 1 e 2) and light curing (all the Groups). After that, an increment of the resin composite Filtek Z-250 (3M/ESPE) was applied and light cured on each tooth. Two of these samples were processed for morphologic characterization of the resin-enamel interface, and the three remainder were dissolved in HCl 6N to observe the resin reproduction of the etching pattern. To evaluate the microtensile bond strength, twenty teeth separated in the same four Groups (n=5) received the application of the adhesives and a block the resin composite Filtek Z250 (3M/ESPE) was incrementally built up on their surfaces. After 24 hours, the microtensile bond strength test was performed and the results analyzed by the Tukey?s test (?=0,05). The fracture pattern was classified in: Type I- interfacial failure, Type II- cohesive failure in enamel, Type III- cohesive failure in bonding resin, Type IV- cohesive failure in enamel and in bonding resin. The self-etching system SE produced shallow demineralization on G and U enamel, resulting in an extremely thin hybrid layer. The ?all in one? adhesive systems PLP and AD were more aggressive than SE, producing microporosities in both G and U enamel. The infiltration of the resin formed a homogenous and uniform hybrid layer. More aggressive morphologic alterations were produced by phosphoric acid in both G and U enamel. This outcomes in a hybrid layer equally continuous and uniform, however thicker. The microtensile bond strength values [Mean (MPa) ± SD] were: SB/U-29.74±7.67; SB/G-31.81±6.65; PLP/U-24.27±5.15; PLP/G-25.01±5.16; AD/U-20.49±5.72; AD/G-20.88±5.54; SE/U-17.19±5.03; SE/G-17.92±3.09. The SB system produced statistically higher bond strength compared to the other adhesive systems. Among the self-etching systems, the best results were obtained with PLP, which was statistically higher than AD that was similar to SE. The G and U conditions didn t show influence on the microtensile bond strength results independent of the adhesive system employed. Despite of the enamel condition, the phosphoric acid produced the highest morphologic alteration. The self-etching systems produced different morphologic features after conditioning. The action of the PLP and AD systems were more effective in comparison to SE for both G and U enamel. There was prevalence of type IV failure pattern for SB, while the type III was more frequent for the self-etching systems

ASSUNTO(S)

materiais dentarios dental enamel esmalte dentario dental materials

ACESSO AO ARTIGO

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