title: Refractive indices of unfilled resin mixtures and cured composites related to color and translucency of conventional and low-shrinkage composites.
abstract: This study correlated the refractive indices (RIs) of unfilled resin mixtures and resin-based composites (RBCs) with color and translucency of conventional and low-shrinkage RBCs. Unfilled resin mixtures based on different ratios of conventional monomers Bisphenol A-glycidyl-methacrylate (BisGMA)/triethyleneglycol-dimethacrylate (TEGDMA) and urethane-dimethacrylate (UDMA)/TEGDMA and a low-shrinkage monomer FIT-852 (FIT, Esstech Inc.)/TEGDMA were used to prepare model RBCs, containing 30 wt % of the organic matrix and 70 wt % of silanated barium-glass fillers (n = 1.553, Esstech Inc.). The RIs of resins were measured on an ABBE refractometer, those of cured RBCs using the Becke-line method in immersion oils. Color and translucency were determined using an AvaSpec-2048 (Avantes BV) spectrometer. The RIs of unfilled resin mixtures decreased with increasing amounts of TEGDMA. Cured RBCs had higher RIs than their respective resin mixtures. BisGMA-based composites were more translucent with significantly lower L* values than FIT- and UDMA-based RBCs. The RIs of unfilled resins positively correlated with cured RBCs (p = 0.001), as did the RIs with translucency (p = 0.001) and color (p = 0.008). Resin mixtures and corresponding RBCs based on UDMA and its modified low-shrinkage version, FIT, showed similar optical properties. The RIs of unfilled resins appeared to be good predictors of the RIs of cured RBCs. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 7-13, 2017.
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, 11000, Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Miletic
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, 11000, Belgrade, Serbia.
authors.forename: Nikola
authors.initials: N
authors.lastname: Jakovljevic
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, 11000, Belgrade, Serbia.
authors.forename: Dragica
authors.initials: D
authors.lastname: Manojlovic
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, 11000, Belgrade, Serbia.
authors.forename: Jovana
authors.initials: J
authors.lastname: Marjanovic
authors.affiliation: University of Belgrade, Faculty of Mining and Geology, Department of Crystallography, 11000, Belgrade, Serbia.
authors.forename: Aleksandra A
authors.initials: AA
authors.lastname: Rosic
authors.affiliation: University of Belgrade, Vinča Institute of Nuclear Sciences, 11001, Belgrade, Serbia.
authors.forename: Miroslav D
authors.initials: MD
authors.lastname: Dramićanin
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D012031:Refractometry
chemical_list: D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: color; composite; low-shrinkage; refractive index; translucency