title: Post-cure depth of cure of bulk fill dental resin-composites.
abstract: OBJECTIVE
  To determine the post-cure depth of cure of bulk fill resin composites through using Vickers hardness profiles (VHN).
  
  
  METHODS
  Five bulk fill composite materials were examined: Tetric EvoCeram(®) Bulk Fill, X-tra base, Venus(®) Bulk Fill, Filtek™ Bulk Fill, SonicFill™. Three specimens of each material type were prepared in stainless steel molds which contained a slot of dimensions (15 mm × 4 mm × 2 mm), and a top plate. The molds were irradiated from one end. All specimens were stored at 37°C for 24h, before measurement. The Vickers hardness was measured as a function of depth of material, at 0.3mm intervals. Data were analysed by one-way ANOVA using Tukey post hoc tests (α=0.05).
  
  
  RESULTS
  The maximum VHN ranged from 37.8 to 77.4, whilst the VHN at 80% of max.VHN ranged from 30.4 to 61.9. The depth corresponding to 80% of max.VHN, ranged from 4.14 to 5.03 mm. One-way ANOVA showed statistically significant differences between materials for all parameters tested. SonicFill exhibited the highest VHN (p<0.001) while Venus Bulk Fill the lowest (p≤0.001). SonicFill and Tetric EvoCeram Bulk Fill had the greatest depth of cure (5.03 and 4.47 mm, respectively) and was significant's different from X-tra base, Venus Bulk Fill and Filtek Bulk Fill (p≤0.016). Linear regression confirmed a positive regression between max.VHN and filler loading (r(2)=0.94).
  
  
  CONCLUSIONS
  Bulk fill resin composites can be cured to an acceptable post-cure depth, according to the manufacturers' claims. SonicFill and Tetric EvoCeram Bulk Fill had the greatest depth of cure among the composites examined.
authors.affiliation: Biomaterials Research Group, School of Dentistry, University of Manchester, Manchester M13 9PL, UK; Department of Restorative Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. Electronic address: alrahlah@hotmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Alrahlah
authors.affiliation: Biomaterials Research Group, School of Dentistry, University of Manchester, Manchester M13 9PL, UK.
authors.forename: N
authors.initials: N
authors.lastname: Silikas
authors.affiliation: Biomaterials Research Group, School of Dentistry, University of Manchester, Manchester M13 9PL, UK; Photon Science Institute, University of Manchester, Manchester M13 9PL, UK.
authors.forename: D C
authors.initials: DC
authors.lastname: Watts
mesh_terms: D000180:Acrylic Resins; D003188:Composite Resins; D001840:Dental Bonding; D006801:Humans; D011140:Polyurethanes; D011176:Post and Core Technique
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes
keywords: Bulk fill; Depth of cure; Microhardness; Post-cure; Resin composites