title: Depth of cure of resin composites: is the ISO 4049 method suitable for bulk fill materials?
abstract: OBJECTIVE
  To evaluate if depth of cure D(ISO) determined by the ISO 4049 method is accurately reflected with bulk fill materials when compared to depth of cure D(new) determined by Vickers microhardness profiles.
  
  
  METHODS
  D(ISO) was determined according to "ISO 4049; Depth of cure" and resin composite specimens (n=6 per group) were prepared of two control materials (Filtek Supreme Plus, Filtek Silorane) and four bulk fill materials (Surefil SDR, Venus Bulk Fill, Quixfil, Tetric EvoCeram Bulk Fill) and light-cured for either 10s or 20s. For D(new), a mold was filled with one of the six resin composites and light-cured for either 10 s or 20 s (n=22 per group). The mold was placed under a microhardness indentation device and hardness measurements (Vickers hardness, VHN) were made at defined distances, beginning at the resin composite that had been closest to the light-curing unit (i.e. at the "top") and proceeding toward the uncured resin composite (i.e. toward the "bottom"). On the basis of the VHN measurements, Vickers hardness profiles were generated for each group.
  
  
  RESULTS
  D(ISO) varied between 1.76 and 6.49 mm with the bulk fill materials showing the highest D(ISO). D(new) varied between 0.2 and 4.0 mm. D(new) was smaller than D(ISO) for all resin composites except Filtek Silorane.
  
  
  CONCLUSIONS
  For bulk fill materials the ISO 4049 method overestimated depth of cure compared to depth of cure determined by Vickers hardness profiles.
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Switzerland. simon.flury@zmk.unibe.ch
authors.forename: Simon
authors.initials: S
authors.lastname: Flury
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hayoz
authors.forename: Anne
authors.initials: A
authors.lastname: Peutzfeldt
authors.forename: Jürg
authors.initials: J
authors.lastname: Hüsler
authors.forename: Adrian
authors.initials: A
authors.lastname: Lussi
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000592:standards; D003764:Dental Materials / Q000737:chemistry* / Q000592:standards; D006244:Hardness; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000592:standards*; D008422:Materials Testing / Q000592:standards; D058105:Polymerization; D062047:Silorane Resins; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C515951:Filtek Supreme Plus; C510379:QuiXfil; D062047:Silorane Resins; D012833:Siloxanes; C553871:Surefil SDR Flow; C501891:Tetric EvoCeram; C488393:Venus (composite resin); C555513:silorane composite resin