Influencia do grau de mineralização do substrato dentinario na resistencia a microtração de tres sistemas adesivos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The purpose of this in vitro study was to investigate the effect of dentin mineralization level: demineralized, normal or hypermineralized, on microtensile bond strength of the adhesive systems Clearfil Liner Bond 2V / Kuraray Co. (CLB), Single Bond / 3M (SB) and OptiBond Solo Plus / Kerr (OSP). 90 freshly extracted incisive bovine teeth were selected, thoroughly cleaned and mechanically polished with wet silicon carbide papers. Teeth were randomly assigned into three groups, which were submitted to different pH-cycling models: Group I - demineralized dentin (DD); Group II - hypermineralized dentin (HD) and Group III normal dentin (ND). Each group, with its specific mineralization pattern, was randomly reassigned into three subgroups, in order to receive one of each adhesive application, according to manufacturers instructions. Resin "crowns" with 5 mm high were incrementally constructed with Filtek Z250 /3M composite resin, and after 24 h of storage in distilled water at 37°C, teeth were prepared to micro-tensile testing. Samples were serially sectioned on a precision cutter in 1 mm slices, parallel to the dental long axis; and with diamond points, the hour glass devices were trimmed resulting in a cross-sectional area of 0.8 mm2. Each specimen was indMdual1y tested on a microtensile device (MT Jig) attached to a universal testing machine / EMIC with a crosshead speed of 0.5 mm/min. After testing, each specimen was visually evaluated. The bond strengths were statistically evaluated with two-way ANOVA and Tukey´s test (p<0.05). The mean values obtained, recorded in MPa, were: ND;SB= 31.05; ND/OSP= 24.49; HD;SB= 23.97; HD/CLB= 19.32; ND/CLB= 19.00; HD/OSP= 17.84; DD/CLB= 15.81; DD;SB= 13.62; DD/OSP= 5.22. The statistical analysis showed a significant (p<0.05) interaction between the adhesive systems and the dentin substrates evaluated. SB and OSP presented the higher tensile bond strength values on ND. In terms of tensile bond strengths to DD, the highest mean values originated from SB and CLB. Regarding the HD, no differences were found among the adhesive systems evaluated. It could not be observed a real benefit from a unique adhesive system in all dentin mineralization levels

ASSUNTO(S)

dentina micro-tensile test bond stength adesivos dentarios adhesive systems dentistica dentin

ACESSO AO ARTIGO

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