Efficacy of two coating agents on the surface hardness of Fuji II and Fuji IX

Many protective materials such as varnishes as well as specially designed agents are used to protect glass ionomer cements against hydration and dehydration. The use of enamel bonding agents is also purposed. This study was conducted to evaluate the efficacy of an enamel bonding agent. Vickers microhardness was used as the criteria for judgment. Forty five discs (2×6 mm) were made from each of the two glass ionomer cements using Fuji II and Fuji IX. They were divided equally into three subgroups, which were protected with either finishing gloss/3M, Margin bond/Coltene or without protection (control). Microhardness of the specimens was evaluated at 24 hours, one week and one month after preparation. Data were analyzed by 3-way ANOVA and Tukey post-hoc test. The highest Vickers hardness number (VHN) for Fuji IX and Fuji II was recorded when protected with Margin bond at 1 month (110.54 ± 6.52 and 106.43 ± 8.30, respectively), whereas the lowest VHN was observed for the control group at 1 day (80.29 ± 6.78 and 62.18 ± 7.46, respectively). There was no significant difference between Fuji II and Fuji IX coated specimens at all time intervals. Protecting the glass ionomer cements with either of the two agents exhibited similar results. Microhardness of the tested glass ionomers increased during the test period; however, the only differences detected were between one day and one month specimens. The performance of enamel bonding agent in protecting the glass ionomers was similar to that of especially designed coating material.