Effect of fluoridated gels on a light-cured glass ionomer cement: an SEM study

This SEM study evaluated the micromorphological effect of a 1.23% acidulated phosphate fluoride gel (Oral-B) (APF) and a neutral 1.1% sodium fluoride gel (Thera-Flur) (Colgate-Hoyt) on the surface of a light-cured glass ionomer cement (Fuji II LC) with or without a protective surface glazing. Glass ionomer (GI) cylinders (area 6.69 mm) were prepared and divided into six groups of 10 specimens each: Group 1: GI; Group 2: GI + APF gel for 4 minutes; Group 3: GI + glaze; Group 4: GI, glaze, APF for 4 minutes; Group 5: GI, neutral fluoride for 4 minutes; Group 6: GI, glaze, neutral fluoride for 4 minutes. The glass ionomer was handled according to manufacturer's instructions, except for the groups using the glaze after light-curing the GI. The glaze resin (Ketac-Glaze) was painted with a brush over the GI surface and cured with visible light (Demetron) for 30 seconds. The fluoride gels were 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 the GI surface considerably and that the glaze protects the GI from the APF gel. The neutral fluoride gel had no significant effect on the GI surface with or without the glaze application.