Abstracts

Indiana University-Purdue University Indianapolis (IUPUI) Objective: The objective was to assess a multiple emission peak light-emitting-diode(LED) light-curing unit (LCU) by measuring the polymerization efficiency through thedegree of conversion (DC) and Knoop microhardness (KHN) of a resin-based pit andfissure sealant at various light curing times and two distances compared to a singleemission peak LED LCU.Method: Sixty disks of resin-based pit and fissure sealant (Delton, DENTSPLY, York, PA)samples (6x1mm) were fabricated (n=5/LCU/group). Prepared samples were polymerizedusing 10, 20 and 40 second curing time at 2 or 4 mm curing distances. The irradiance andradiant exposure received on the top/bottom surfaces of the samples were measured usingthe Managing Accurate Resin Curing-Resin Calibrator (MARC-RC) system. The sampleswere stored at 37C for one hour. Then, the DC (n=3/surface) and KHN (n=5/surface)measurements were collected on the top and bottom surfaces using Attenuated TotalReflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and a microhardnesstester (Instron) utilizing 25-gm at 10 seconds dwell time, respectively. Multiple-wayANOVA was performed followed by Tukey test (=0.05).Result: The irradiance from the multiple emission peak LED LCU was significantly higherthan the single emission peak LED LCU (1312.6 and 768.3 mW/cm2) respectively.Moreover, the multiple emission peak LED LCU displayed significantly higher DC(82.5%) and microhardness (26.2 KHN) compared to the single emission peak LED LCU(75.5% DC and 21.2 KHN) when curing samples at 2 and 4 mm curing distances assessedusing 10, 20 and 40-second curing times. The 10 second cure at 4 mm showed significantlylower DC and KHN values compared to the other groups.Conclusion: The multiple emission peak LED LCU demonstrated significantly higherirradiance, DC and KHN compared to the single emission peak LED LCU on a resin-basedpit and fissure sealant at 2 and 4 mm curing distances and 10, 20 and 40 second curingtimes. Therefore, the multiple emission peak LED LCU performed higher than the singleemission peak LED LCU.Advisors/Committee Members: Soto, Armando E..