Polymerization Activity of New Resin Composite Including Radical Amplifier

Objectives: The aim of this study was to evaluate the polymerization activity of new flowable resin composite (ESTELITE UNIVERSAL FLOW; EUF) that includes radical amplifier as a composition of polymerization initiator system named ‘RAP technology’.
Methods: Three kinds of different flowable resin composites were tested: EUF (Tokuyama Dental Corporation, RAP technology), EUF-CQ (experimental resin composite, conventional photo initiator system, camphorquinone/amine), EUF-CQ2 (experimental resin composite, containing 1.6 times the amount of camphorquinone and amine). Polymerization activity was evaluated by comparing Vickers Hardness Number (VHN) and degree of conversion (DC) under different light curing time. VHN was measured at the curing surface using micro hardness tester (n = 6, MMT-X7, MATSUZAWA). DC was determined by means of Raman spectroscopy and measurements were done at the bottom surface of the cured resin composite (n = 3, 2 mm thickness, NRS-7100, JASCO). Each samples were cured by halogen light (Optilux LCT, 800 mW/cm²) for 10 and 30 seconds. The Data was submitted to one-way ANOVA with post-hoc Turkey’s HSD test (p<0.05).
Results: The following table shows VHN and DC of the tested resin composites.
Conclusions: EUF using RAP technology shows the highest and even VHN and DC in both 10 and 30 seconds of light curing compared to conventional photo initiator system. These results indicate that RAP technology achieves the shortest curing time for resin composite.