Effect Of Aging On Mechanical Properties, Fluoride Release And Recharging, Water Sorption And Solubility Of Ceramic Reinforced Glass Ionomer: An In Vitro Study

Abstract

This study aimed to evaluate the effect of aging on compressive strength, modulus of elasticity, fluoride release, fluoride release after recharge, water sorption and solubility of ceramic-reinforced glass ionomer (Amalgomer CR) in comparison to a resin-modified (Fugi VIII) and a high-viscosity (Equia fil) glass ionomers. A total of 162 specimens were prepared, 54 for each restorative material. Compressive strength and modulus of elasticity were tested following the ISO Guidelines No. 9917-1:2007(E). Cylindrical specimens (4 mm diameter, 6 mm thickness) were prepared and tested after 24 hours and 6 months of storage in deionized water. For fluoride release and fluoride release after recharge, 6 mm diameter and 3 mm thickness disc specimens were prepared according to the manufacturer’s instructions and stored in deionized water at 37◦C until the time of testing (24, 48 hours, 7 days, 1, 3 and 6 months). Water sorption and solubility were evaluated following the ISO guidelines No. 4049:2009 (E). Disc shaped specimens (15 mm diameter, 1 mm thickness) were prepared and tested after 7 days, 1, 3, and 6 months storage in distilled water. Representative samples of the tested glass ionomers after 7 days and 6 months water storage (water sorption and solubility specimens) were assessed using environmental scanning electron microscope. Two-ways ANOVA and one-way ANOVA followed by pairwise comparisons with Bonferroni correction were used for statistical analysis of data. The results of this study revealed that Amalgomer CR and Fugi VIII showed the highest compressive strength with no significant difference between the two groups whereas, Equia fil showed the lowest value after 24 hours. After 6 months of aging, the compressive strength of Amalgomer CR was significantly decreased. For Modulus of elasticity results, Amalgomer CR and Equia fil showed the highest modulus of elasticity whereas, Fugi VIII showed the lowest modulus after 24 hours of water storage. The modulus of elasticity of all tested groups was decreased after 6 months aging in deionized water