Effect of APF gel on light-cured glass ionomer cements: an SEM study

This SEM study evaluated the micro morphological effect of a 1.23% acidulated phosphate fluoride gel (Oral-B)(APF) on the surface of VariGlass and Vitrebond light-cured glass ionomer cements with or without Ketac Glaze protective surface glazing. Glass ionomer (GI) cylinders (area 6.69 mm) were prepared and divided into six groups of 10 specimens each: Group 1: VariGlass; Group 2: VariGlass + APF gel for 4 minutes; Group 3: VariGlass + Ketac Glaze; Group 4: VariGlass + Ketac Glaze + APF for 4 minutes; Group 5: Vitrebond; Group 6: Vitrebond + APF gel for 4 minutes; Group 7: Vitrebond + Ketac Glaze; Group 8: Vitrebond + Ketac Glaze + APF for 4 minutes. The cements were handled according to manufactures' instructions, except for the groups using the glaze after light-curing the GI. The Ketac Glaze resin was painted with a brush over the GI surface and cured with visible light (Demetron) for 30 seconds. The fluoride gel was left in contact with the surface for 4 minutes, rinsed and dried. All specimens were then mounted on aluminum stubs, coated and evaluated under the SEM. The results indicated that the APF gel etches both GI surfaces considerably and that the unfilled resin glaze protects the GIs from the erosive effects of the APF gel.