title: Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites.
abstract: OBJECTIVE
  To study the effect of a low-shrinkage methacrylate monomer and monoacylphosphine oxide photoinitiator on color, translucency, and color stability of model resin-based composites (RBCs).
  
  
  METHODS
  Four micro-hybrid RBCs were prepared containing barium-glass fillers in bisphenol A-glycidyl-methacrylate (BisGMA) and triethyleneglycol-dimethacrylate (TEGDMA) or urethane-based low-shrinkage monomer FIT-852 (FIT; Esstech Inc.) and TEGDMA matrix. Camphorquinone (CQ)/amine or Lucirin TPO were used as photoinitiators. Commercial low-shrinkage RBCs (Charisma Diamond, Heraeus Kulzer and N'Durance, Septodont) and conventional RBCs (Tetric EvoCeram, Ivoclar Vivadent and Filtek Z250, 3M ESPE) were used as controls. Color and translucency were measured using Thermo Scientific Evolution (Thermo Fisher Scientific) and SpectroShade™ Micro (MHT Optic Research) spectrophotometers. Color stability was evaluated after immersion in black tea (pure, with milk or lemon) and distilled water. Data were analyzed using analyses of variance with Tukey's post-test (α=0.05).
  
  
  RESULTS
  Photoinitiators had no significant effect on baseline color. Initially whiter FIT-based RBCs showed greater staining in all staining solutions than BisGMA-based RBCs. TPO-containing RBCs showed better color stability than CQ-containing RBCs irrespective of the base monomer. Tea and tea with lemon induced greatest color changes. Adding milk to tea significantly reduced material staining.
  
  
  CONCLUSIONS
  Urethane-based low-shrinkage monomer FIT and conventional BisGMA affected color, translucency and color stability of their respective RBCs. Despite being used in posterior teeth, low-shrinkage RBCs are expected to have favorable optical and esthetic properties. Manufacturers are urged to provide information on optical properties of monomers and monomer mixtures in their low-shrinkage RBCs to allow understanding of interaction with fillers and photoinitiators.
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, Rankeova 4, Belgrade, Serbia.
authors.forename: Dragica
authors.initials: D
authors.lastname: Manojlovic
authors.affiliation: University of Belgrade, Institute of Nuclear Sciences "Vinča", P.O. Box 522, Belgrade, Serbia.
authors.forename: Miroslav D
authors.initials: MD
authors.lastname: Dramićanin
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, Rankeova 4, Belgrade, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Lezaja
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Pong
authors.initials: P
authors.lastname: Pongprueksa
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Van Meerbeek
authors.affiliation: University of Belgrade, School of Dental Medicine, DentalNet Research Group, Rankeova 4, Belgrade, Serbia. Electronic address: vesna.miletic@stomf.bg.ac.rs.
authors.forename: Vesna
authors.initials: V
authors.lastname: Miletic
mesh_terms: D000818:Animals; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D002957:Citrus; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D008422:Materials Testing; D008892:Milk; D044367:Phase Transition; D010720:Phosphines / Q000737:chemistry; D058567:Photoinitiators, Dental / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D013499:Surface Properties; D013662:Tea
chemical_list: C084111:Charisma composite resin; D003188:Composite Resins; C444701:Filtek Z250; C551012:N'Durance composite resin; D010720:Phosphines; D058567:Photoinitiators, Dental; D011109:Polymethacrylic Acids; D013662:Tea; C501891:Tetric EvoCeram; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D002164:Camphor; C553149:camphorquinone
keywords: BisGMA; Camphorquinone; Color; Composite; Low-shrinkage; Lucirin TPO; Photoinitiator; Resin; Staining; Translucency