title: Curing characteristics of flowable and sculptable bulk-fill composites.
abstract: OBJECTIVE
  The aim of this study was to determine and correlate the degree of conversion (DC) with Vickers hardness (VH) and translucency parameter (TP) with the depth of cure (DoC) of five bulk-fill composites.
  
  
  METHODS
  Six specimens per group, consisting of Tetric EvoCeram Bulk Fill ("TEC Bulk," Ivoclar Vivadent), SonicFill (Kerr), SDR Smart Dentin Replacement ("SDR," Dentsply), Xenius base ("Xenius," StickTech; commercialized as EverX Posterior, GC), Filtek Bulk Fill flowable ("Filtek Bulk," 3M ESPE), and Tetric EvoCeram ("TEC," control), were prepared for DC and VH: two 2-mm-thick layers, each light-cured for 10 s; one 4-mm bulk-fill, light-cured for 10 or 20 s; and one 6-mm bulk-fill, cured for 20 s. DC was measured using a Fourier-transform infrared spectrometer, VH using a Vickers hardness tester. DoC and TP were measured using an acetone-shaking test and a spectrophotometer, respectively. Data were analyzed using ANOVA and Pearson's correlation (α = 0.05).
  
  
  RESULTS
  DC and VH ranged between 40-70 % and 30-80 VHN, respectively. TEC Bulk, Xenius, and SonicFill, bulk-filled as 4-mm-thick specimens, showed bottom-to-top hardness ratios above 80 % after 20 s curing. A positive linear correlation was found for bottom DC and VH. An average DC ratio of 0.9 corresponded to a bottom-to-top VH ratio of 0.8.
  
  
  CONCLUSIONS
  Sculptable bulk-fills require 20 s, whereas 10 s curing time was sufficient for flowable bulk-fills using a high-intensity LED unit.
  
  
  CONCLUSIONS
  Clinicians should be aware that longer curing times may be required for sculptable than flowable bulk-fill composites in order to achieve optimal curing characteristics.
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Kapucijnenvoer 7, block a - box, 7001, Leuven, Belgium.|School of Dental Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Miletic
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Kapucijnenvoer 7, block a - box, 7001, 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, Kapucijnenvoer 7, block a - box, 7001, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: De Munck
authors.affiliation: Department of Chemistry, KU Leuven (University of Leuven), Leuven, Belgium.
authors.forename: Neil R
authors.initials: NR
authors.lastname: Brooks
authors.affiliation: BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Kapucijnenvoer 7, block a - box, 7001, Leuven, Belgium. bart.vanmeerbeek@med.kuleuven.be.
authors.forename: Bart
authors.initials: B
authors.lastname: Van Meerbeek
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D006244:Hardness; D006245:Hardness Tests; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D058105:Polymerization; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C000618653:EverX Posterior; C000614713:Filtek Bulk Fill; C000614714:SDR composite; C000613185:SonicFill; C501891:Tetric EvoCeram; C111840:flowable hybrid composite
keywords: Bulk-fill; Composites; Degree of conversion; Depth of cure; Hardness; Translucency