Effect of finishing technique on the microleakage and surface texture of resin-modified glass ionomer restorative materials

Purpose: The purpose of this study was to evaluate the effects of wet and dry finishing/polishing procedures on the microleakage and surface texture of resin-modified glass ionomer (RMGI) restorative materials. Materials and methods: Class V cavity preparations were made at the cemento–enamel junction (CEJ) on the buccal and lingual surface of 30 extracted human molars. The teeth were restored in three groups of 10 (20 preparations in each group) using Fuji II LC and Vitremer, both RMGIs, and Fuji II, a capsulated conventional glass ionomer cement (control). One restoration per tooth was finished/polished with copious applications of water and the other was finished/polished without water. All restorations were finished/polished using a sequence of four abrasive disks. Finishing/polishing was initiated according to manufacturers' instructions—immediately after light-curing Fuji II LC and Vitremer, and 15 min after placement for Fuji II. The specimens were thermocycled and subjected to a silver nitrate leakage test. Each tooth was sectioned buccolingually and examined with an optical microscope at 40× to determine the extent of microleakage at enamel and dentin margins. The data were subjected to a non-parametric statistical analysis. To evaluate surface roughness after polishing, three disks each of Vitremer and Fuji II LC were fabricated in Teflon molds. One disk of each material was not finished/polished (control). The others were finished/polished using Sof-Lex abrasive disks. One specimen of each material was kept wet during all finishing/polishing procedures, while the other was kept dry. Atomic force microscopy was used to determine the average roughness ( R a) of the specimens. Results: For each material, microleakage at the enamel margin was very slight. Leakage of the conventional glass ionomer Fuji II was severe at dentin margins. Statistical analysis indicated that both Vitremer and Fuji II LC had significantly less leakage than Fuji II, and that Vitremer had significantly less leakage than Fuji II LC ( p