Degree of conversion of dual-polymerizing cements light polymerized through monolithic zirconia of different thicknesses and types

• Published in: The Journal of prosthetic dentistry 2015-07, Vol.114 (1), p.103-108
• Main Authors: Sulaiman, Taiseer A., BDS, Abdulmajeed, Aous A., BDS, PhD, Donovan, Terrence E., DDS, Ritter, André V., DDS, MS, MBA, Lassila, Lippo V., DDS, MSc, Vallittu, Pekka K., DDS, PhD, Närhi, Timo O., DDS, PhD
• Format: Article
• Language: English
• Subjects: Ceramics - chemistry; Dental Materials - chemistry; Dentistry; Humans; Light; Light-Curing of Dental Adhesives - methods; Materials Testing; Polymerization; Radiation Dosage; Resin Cements - chemistry; Resin Cements - radiation effects; Self-Curing of Dental Resins - methods; Spectroscopy, Fourier Transform Infrared - methods; Surface Properties; Time Factors; Yttrium - chemistry; Zirconium - chemistry
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1016/j.prosdent.2015.02.007

Abstract 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 μm, placed under a 10×10 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 S10 (3M-ESPE, 1200 mW/cm2 ). 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 (α=.05). Results Light irradiance and radiant exposure decreased as the thickness of the specimen increased ( P