title: Effect of pulse-delay curing on in vitro wall-to-wall contraction of composite in dentin cavity preparations.
abstract: OBJECTIVE
  To determine the effect of pulse-delay curing of resin composite on marginal gap formation in dentin cavity preparations.
  
  
  METHODS
  Cylindrical cavities were prepared in extracted human molar dentin and were distributed into 8 groups (A-H). The cavity preparations were treated with a dentin-bonding agent (Prime & Bond NT) and filled with a light-cured resin composite (Z100). The restorations were irradiated initially for 1, 2 or 3 seconds at a power density of 425 mW/cm2. Following water storage for varying time intervals, the restorations were re-exposed for 10 seconds at 750 mW/cm2. Marginal gap formation was measured by light microscopy after 20 minutes of water-storage, and the wall-to-wall contraction was calculated as the widest gap in percent of cavity diameter.
  
  
  RESULTS
  Pulse-delay curing in combination with a waiting time of at least 1 minute between exposures reduced wall-to-wall contraction in dentin cavities compared to continuous-cure control.
authors.affiliation: Department of Dental Materials, School of Dentistry, University of Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Sahafi
authors.forename: A
authors.initials: A
authors.lastname: Peutzfeldt
authors.forename: E
authors.initials: E
authors.lastname: Asmussen
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003737:Dental Cavity Preparation; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008027:Light; D008422:Materials Testing; D008963:Molar; D011109:Polymethacrylic Acids / Q000737:chemistry; D012822:Silicon Dioxide; D013223:Statistics as Topic; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015040:Zirconium
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; C083568:Z100 composite resin; D014867:Water; D012822:Silicon Dioxide; D015040:Zirconium