Effects of the color components of light-cured composite resin before and after polymerization on degree of conversion and flexural strength / 대한치과보존학회지

ABSTRACT

OBJECTIVES: This study investigated the effects of the color components of light-cured composite resin before and after polymerization on degree of conversion (DC) and biaxial flexural strength (FS). MATERIALS AND METHODS: Four enamel shades (A1, A2, A3, A4) and two dentin shades (A2O, A3O) of Premisa (Kerr Co.) and Denfil (Vericom Co.) were evaluated on their CIE L*, a*, b* color components using the spectrophotometer before curing, after curing and at 7 day. The DC of same specimens were measured with Near-infrared spectrometer (Nexus, Thermo Nicolet Co.) at 2 hr after cure and at 7 day. Finally, the FS was obtained after all the other measurements were completed at 7 day. The correlations between each color component and DC and FS were evaluated. RESULTS: The light-curing of composite resin resulted in color changes of Premisa in red-blue direction and Denfil in green-blue direction. The DC and FS were affected by product, time and shade (3-way ANOVA, p < 0.05) and product and shade (2-way ANOVA, p < 0.05), respectively. Premisa only showed a significant correlation between the DC and CIE a* component - before and after polymerization (Pearson product moment correlation, p < 0.05). The FS of Premisa showed significant negative correlations with CIE a* and CIE b* components. CONCLUSIONS: The DC and FS of the light-curing composite resin were affected by the color components of the material before and after polymerization.