Evaluation of Water Sorption and Solubility, Fluoride release and Microhardness of One Step Versus Conventionally Placed Glass Ionomer Restorative Material

Abstract

Objectives: This in vitro study compared a one step placed glass ionomer (GI), Ketac Universal Aplicap (KUA), with a conventionally placed GI, Ketac Molar Aplicap (KMA), with and without resin coating, regarding water solubility and solubility, fluoride release, and microhardness. Materials and Methods: A total of 120 samples were prepared, 40 for each test (n=10 per subgroup). Water sorption and solubility were determined according to ISO 4049 after 7 days of immersion. Fluoride release was quantified using calibrated fluoride ion selective electrode at 1 and 7 days. Vickers microhardness was measured under a 50 g load applied for 10 s. Results: coating statistically significantly reduced solubility in both materials (KMA: p = 0.003; KUA: p = 0.001) moreover, water sorption did not differ statistically significantly among the groups. Non coated KMA exhibited statistically significant higher solubility than non coated KUA (165.36 ± 3.110,137.23 ± 4.291 μg/mm³; p = 0.001) respectively, and coating also statistically significantly reduced fluoride release in both materials at 1 and 7 days (p = 0.001); release increased statistically significantly from day 1 to 7 days (p < 0.05), and coated KUA released more fluoride than coated KMA at 7 days (3.47 ± 0.316, 2.89 ± 0.422 ppm; p = 0.039) respectively. Coating statistically significantly improved microhardness only for KUA (p = 0.043). Conclusion: Resin coating improved the stability and microhardness of
both GI but attenuated their fluoride release, and the one step material did not behave equivalently to the conventionally placed material under coating.