A comparison of the bond strength to enamel and dentin of two compomers: an in vitro study.

The aim of this study was to evaluate the bond strength of two resin-reinforced glass ionomer cements to etched and unetched enamel and to dentin. Thirty-six noncarious human premolar teeth were used. Flat buccal and lingual surfaces were prepared. Dyract and Compoglass were used. The teeth were distributed at random into six groups of six teeth each. The materials were handled according to manufacturers' instructions. In groups 1 and 3 the enamel was etched with 37 percent phosphoric acid. All samples were sheared with an Autograph AG5 machine at a crosshead speed of 0.5 mm/min. Two way ANOVA and comparison with the Tukey test were used to evaluate the results. These showed that on etched enamel Dyract had a significantly higher bond strength (p = 0.02); on unetched enamel Compoglass had a statistically higher bond strength (p = 0.003), and on dentin the materials provided the same bond strength. Overall, disregarding surfaces, there was no difference between the two materials.