| Summary: | 碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 90 === The purpose of this study was to investigate the polymerization shrinkage and microhardness of resin composites under alternative curing modes by various curing machine. Forty EA-00-031DE-350 strain gauges (Measurements Group, Inc., Raleigh, NC, USA) were tested for polymerization shrinkage. Sixty four resin specimens (Prodigy® and Heliomolar®) were cured by one of four modes as following. Although each mode has their own light intensity and different irradiation time, but the final energy density is the same (16000 mJ/cm²).
I. Conventional (XL3000): 40 sec at 400mW/cm².
II. Boost (Apollo 95E): 13.3 sec at 1200 mW/cm².
III. Soft-start (Optilux 501): Initially at 100 mW/cm², increasing exponentially to 1000 mW/cm² in the first 10 sec. Then maintains at 1000 mW/cm² for the final 10.5 sec.
IV. Pulse activation (Elipar Trilight): Initial 2 sec at 400 mW/cm², a 5-minute hiatus and an additional exposure of 19 sec at 800 mW/cm².
The data of polymerization shrinkage and hardness number were subjected to ANOVA, t-test analysis at a level of significance of p=0.05. With the same energy density (16000mJ/cm²), various curing modes resulted in the same shrinkage stress but different shrinkage dynamics and bottom/top hardness ratio.
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