科研之友
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摘要
Statement of problem. Monolithic zirconia restorations are increasingly common. Dual-polymerizing cements have been advocated for cementation. The opacious nature of zirconia restoration can attenuate light, compromising optimal resin polymerization and eventually restoration debonding. Purpose. The purpose of this in vitro study was to evaluate the influence of material thickness on light irradiance, radiant exposure, and the degree of monomer conversion (DC) of 2 dual-polymerizing resin cements light-polymerized through different brands of monolithic zirconia. Material and methods. Dual-polymerizing resin cements (RelyX Ultimate; 3M-ESPE, and Variolink II; Ivoclar, Vivadent) were mixed according to the manufacturers' instructions with a film thickness of 40 mu m, placed under a 10x10 mm specimen of monolithic zirconia (Prettau Anterior by Zirkonzahn, Katana by Noritake, BruxZir by Glidewell, and Zenostar by Wieland) and a zirconia core control (ICE zirkon by Zirkonzahn) at various thicknesses (0.50, 1.00, 1.50, and 2.00 mm, n=5 of each thickness). Each specimen was irradiated for 20 seconds (RelyX Ultimate) and 40 seconds (Variolink II) with Elipar 510 (3M-ESPE, 1200 mW/cm(2)). The amount of irradiance and radiant exposure was quantified for each specimen. Fourier transform infrared spectroscopy was used to measure the DC from the bottom surface of the resin. Statistical analysis was performed with 2-way ANOVA and post hoc Tukey honest significant difference (HSD) tests (alpha=.05). Results. Light irradiance and radiant exposure decreased as the thickness of the specimen increased (P<.05) regardless of the brand. The ranking from least to highest was BruxZirConclusion. The thickness of zirconia affects the DC of resin-based cements. The DC of the resin cements differed significantly between cements and among zirconia brands. More polymerizing time may be needed to deliver sufficient energy through some brands of zirconia.
- 出版日期2015-7
