Influence of photocuring and storage time on the volumetric change of resin modified glass ionomer cements

Abstract

AIM: This study evaluated the effect of photoativation and storage on the hygroscopic expansion of resin modified glass ionomers (Vitremer-3M/ESPE, Fuji II LC-GC Int., Vitro Fil LC-DFL). MATERIAL AND METHODS: The RMGIC were manipulated according to the manufacturer’s instructions, inserted into a mold and kept in a darkness box for 15 minutes. Then, the samples were distributed into four groups (n=5): light-cured for 20s, light-cured for 40s, light-cured for 60s and not light-cured (control group).  Each sample was storage in distilled water at 37ºC. The measurements of volumetric changes were made in three different times of storage: 24 hours, 7 days and 30 days. Volumetric changes were determined using Archimedes principle. Means and standard deviations  values were analyzed by three-way analysis of variance and  Tukey’s test to compare significance between the groups (?=0,05). RESULTS: All materials underwent volumetric expansion after 30 days. Vitremer showed the less expansion when no light-cured. The time of light-cure did not influence the volumetric change, except for Fuji II LC, that showed great expansion when activated for 60s. Vitro Fil LC showed some degree of shrinkage after 7 days. CONCLUSION: This study concluded that photocuring can influence the volumetric change of resin modified glass ionomer cement.