Comparison of the bond strength between the glass ionomer and composite resin, with and without acid etching

Abstract

The aim of this study was to determine whether the use of acid etching on glass ionomer (Vitremer) improves the adhesion strength with the composite resin. 30 inlay glass ionomer (Vitremer) were analyzed with 2mm thick and 12 mm diameter, laid above a cylindrical acrylic block with 4 cm high and 2 cm diameter. Once made these 30 samples, were separated into three groups of 10. The first group resin restoration was made without using phosphoric acid, 2 layers of adhesive on the glass ionomer were applied and then 3mm of composite resin were placed. In the second group, 35% phosphoric acid was placed for 15 seconds on the glass ionomer prior to placement of adhesive system and resin, and finally in the third group was placed phosphoric acid for 30 seconds prior to placement of the adhesive systems and resin. The samples were stored in distilled water at 37 ° C for 5 days before being failed in shear. The adhesion strength was calculated in megapascals and statistically analyzed. The averages were compared with the methods of Bonferroni and Tukey Kramer, calculated at a 0,05 significance level.

Of all the samples analyzed, group 1 had an average of 4,73 MPa being the group with the highest force recorded, followed by group 2 with an average of 4,36 MPa and finally group 3 with less force registered an average of 3,90 MPa. When performing statistical analyzes results in which there were no statistically significant differences among the three groups were obtained. In the test of equal variances Bonferroni test, the three groups presented a value of 1,0 which is higher than 0,05, therefore there are no significant difference. Using Tukey Kramer test, a comparative study was made between the three groups and it was found that the group 1 versus group 2 showed a value of 0,922, group 1 versus group 3 presented a value of 0,665 and finally group 2 versus group 3 presented a value of 0,880. Therefore, the three groups had higher than 0.05, which determines that they are not significantly different. As a conclusion, the use of phosphoric acid on glass ionomer (Vitremer) may or may not be omitted in an operative procedure using composite resin.