The effects of surface treatments on shear bond strengths of light-cured and chemically cured glass ionomer cements to enamel

Shin, Kang Seob; Lee, Ki Soo

Abstract

The purpose of this study was to evaluate the effects of surface conditioning with 10% polyacrylic acid, etching with 38% phosphoric acid, and polishing with a slurry of pumice on shear bond strengths of light-cured glass ionomer cement, chemically cured glass ionomer cement, and a composite resin to enamel, and to observe the failure patterns of bracket bondings. Shear bond strengths of glass ionomer cements were compared with that of a composite resin. Metal brackets were bonded on the extracted human bicuspids after enamel surface treatments, and samples were immersed in the 37degrees C distilled water bath, and shear bond strengths of glass ionomer cements and a composite resin were measured on the Instron machine after 24hrs passed, and the deboned samples were measured in respect of adhesive remnant index. Scanning electron micrographs were taken of enamel surfaces after various treatments. The data were evaluated and tested by ANOVA and Duncan's multiple range test, and those results were as follows. 1. Shear bond strength of light-cured glass ionomer cement showed statistically higher than that of chemically cured glass ionomer cement. 2. Shear bond strengths of light-cured and chemically cured glass ionomer cements to enamel treated with 10% polyacrylic acid and 38% phosphoric acid showed statistically higher than those with a slurry of pumice. 3. According to scanning electron micrographs, enamel surface conditioned with 10% polyacrylic acid is slightly etched and cleaned, that etched with 38% phosphoric acid is severely etched, and that polished with a slurry of pumice is irregulary scretched and not completely cleaned. 4. After debonding, light-cured glass ionomer cement to enamel treated with 10% polyacrylic acid showed less residual materials on the enamel surface than composite resin to enamel etched with 38% phosphoric acid. 5. There was no significant difference in the shear bond strength of light-cured glass ionomer cement to enamel treated with 10% polyacrylic acid and that of composite resin to enamel etched with 38% phosphoric acid.