Effect of glass ionomer surface hardness by using LED, calcium chloride and plasma Arc : (In-vitro Study) /

Abstract

To measure and compare the effect of LED, Calcium chloride solution, Calcium chloride gel and Plasma Arc on the surface hardness of conventional Fuji IX GIC twice, at baseline and after pH cycling. A total of 50 encapsulated conventional Fuji IX GP FAST GIC were mixed to form disc-shaped specimens using a split-teflon mold. They were divided into 5 groups of 10 specimens each. Group 1 (control): specimens were left to set conventionally without any treatment. Group 2 (LED): the top surface of the specimens was irradiated for 40s by LED during setting. Groups 3 (CaCl2-Sol.): the top surface of the specimens was treated with CaCl2 solution for 2 minutes during setting. Group 4 (CaCl2- Gel): the top surface of specimens was treated with CaCl2 gel for 2 minutes during setting. Group 5 (Plasma Arc): the top surface of the specimens was irradiated with Plasma Arc curing device for 10s during setting. Next, baseline surface hardness was measured by using Vickers Micro-Hardness Tester. Finally, all groups were exposed to a pH cycling protocol using 5% acetic acid, pH=3, for 14 days. Finally, surface hardness was re-measured after pH cycling. The results showed significantly higher values for the surface hardness of Fuji IX GIC specimens treated by: LED, Calcium Chloride and Plasma Arc in comparison to the control untreated specimens. Plasma Arc showed the highest significant hardness values, compared to the other tested groups. However, LED, CaCl2 solution and CaCl2 gel showed comparable results. CaCl2 solution group showed significantly lower values compared to LED irradiated group. Finally, pH cycling had significant adverse effects on the overall hardness of all tested groups, showing a decrease in surface hardness except for the Plasma Arc irradiated group.