Effectiveness of surface protection of resin modified glass ionomer cements evaluated spectrophotometrically

The effectiveness of four surface protectors for resin-modified glass ionom er cements was evaluated by spectrophotometrically determining dye uptake. Ninety specimens, 3.0 mm in diameter and 1.0 mm in height, were made with P hotac-Fil, Fuji II LC and Vitremer and divided into six groups for each mat erial. Positive and negative controls were not protected while experimental specimens were protected with proprietary glaze, nail varnish, flowable re sin and glaze. The discs were immersed in 0.1% methylene blue solution for 10 minutes after mixing, except for those negative control specimens that w ere immersed in deionized-water. After 24 hours, the specimens were washed and the protectors trimmed with Sof-Lex discs. The specimens were then remo ved from the matrixes and individually placed in 1.5 mL of 65% nitric acid for five hours. The absorbance was determined spectrophotometrically at 590 nm, Dye uptake was expressed in mug dye/specimen. The data were analyzed b y two-way ANOVA and Tukey-Kramer tests. All surface protectors tested were effective. For Fuji II LC and Vitremer no differences were observed among t ested protections. For Photac-Fil, nail varnish showed better performance t han the proprietary glaze.