Influence of acid etching on shear strength of different glass ionomer cements

Aim: To assess the influence of dental etching on the shear strength of different glass ionomer cements. Methods: The crown of 60 bovine incisors was prepared to obtain a flat, smooth surface, were attached to a PVC tube and randomly divided into six groups: Group 1 – Riva Self Cure without etching; Group II – Riva Self Cure with pre-etching; Group III – Maxxion R without etching; Group IV – Maxxion R with pre-etching; Group V – KetacTMMolar Easymix without etching; and Group VI – KetacTMMolar Easymix with pre-etching. Etching was performed with 10% polyacrylic acid for 30 s. A standardizing device was used for preparation of the test specimens (SBS Test Method). Following preparation, the specimens were stored in distilled water at 37o C for 24 h. The shear test was performed on a Kratos universal testing machine at a crosshead speed of 0.5 mm/min. The specimens were then viewed under a stereomicroscope at a magnification of x90 for analysis of fractures. Results: The results revealed that pre-etching increased the shear strength of Riva glass ionomer cement (SDI) alone, whereas no statistically significant differences were found with regard to the other materials tested. Conclusions: Pre-etching with 10% polyacrylic acid for 30 s increased the shear strength of Riva glass ionomer cement.