Degree of Conversion and Hardness of Two Different Systems of the VitrebondTM Glass Ionomer Cement Light Cured with Blue LED

This study investigated the physicochemical properties of the new formulation of the glass ionomer cements through hardness test and degree of conversion by infrared spectroscopy (FTIR). Forty specimens (n = 40) were made in a metallic mold (4 mm diameter x 2 mm thickness) with two resin-modified glass ionomer cements, Vitrebond TM and Vitrebond TM Plus (3M/ ESPE). Each specimen was light cured with blue LED with power density of 500 mW/cm2 during 30 s. Immediately after light curing, 24h, 48h and 7 days the hardness and degree of conversion was determined. The Vickers hardness was performed by the MMT-3 microhardness tester using load of 50 gm force for 30 seconds. For degree of conversion, the specimens were pulverized, pressed with KBr and analyzed with FT-IR (Nexus 470). The statistical analysis of the data by ANOVA showed that the Vitrebond TM and Vitrebond TM Plus were no difference significant between the same storage times (p > 0.05). For degree of conversion, the Vitrebond TM and Vitrebond TM Plus were statistically different in all storage times after light curing. The Vitrebond TM showed higher values than Vitrebond TM Plus (p < 0.05). The performance of Vitrebond TM had greater results for degree of conversion than Vitrebond TM Plus. The correlation between hardness and degree of conversion was no evidence in this study.