Barzilai University Medical Center

19 Research Day 2020 Barzilai University Medical Center 9 THE MICROHARDNESS OF 3 GLASS IONOMER CEMENTS (GIC) DURING SETTING IN COMPARISON TO COMPOSITE AND THE EFFECT OF ENERGY DURING SETTING OF GIC Fanny Hershkovitz, Uri Zilberman Pediatric Dental Clinic, Barzilai Medical University Center, Ashkelon Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel. Background Glass ionomer cements (GIC) are a group of materials used in dentistry for restorations in deciduous and permanent teeth. GICs are bonded chemically to enamel and dentin and release significant fluoride to the surroundings. Objectives To examine the microhardness of 3 different GIC during setting, in comparison with composite and to analyze the effect of energy application on their microhardness. Methods and materials Discs of EQUIA (GC Co. Japan), Ketac Molar (3M/ESPE, Germany), and Riva (SDI, Australia) were examined for microhardness using Vickers indentations during setting after 15,20,25,30,60 min, 24 hours and 7,15 days and compared to Z250 (3M/ESPE, Germany). The effect of energy application during setting of GIC was compared to normal setting. Results During the first 60 min the composite showed better results (30-40 Vickers value compared to 12-25 for GIC), but after 24 hours the results for GIC were similar or higher than the composite. Between the GIC examined the EQUIA (GC Co. Japan) showed the highest results during the first 30 minutes of setting, but latter all three GIC showed similar results. Energy application during setting showed an increase of microhardness results during all the examined period by 20-40%. Conclusions Microhardness of GIC is similar to composite after the first 24 hours after application and is higher than composite after 8-15 days. The application of heat energy to GIC using a heating device improved the surface microhardness significantly. The temperature to be used is around 50 o C for 30 or 60 seconds in order not to cause irreversible damage to the pulp .