title: Monomer conversion in dual-cured core buildup materials.
abstract: OBJECTIVE
  To examine the impact of self-curing (SC) and light-curing (LC) mechanisms on the curing efficiency of dual-cured buildup restorative materials (DCB).
  
  
  METHODS
  The DCB materials tested were: Clearfil DC Core Automix (CD), Cosmecore DC (CM), LuxaCore DC (LX) and MultiCore DC Flow (MC). The SC material Clearfil Core New Bond (CN) and the LC material Clearfil Photo Core (CP) were used as controls. Specimens (Ø=4 mm, d=1 mm, n=4) of DCB materials prepared without light-exposure were tested after 10-, 20-, 30- and 60-minutes of storage in dark and dry conditions (37°C), whereas DCB specimens light-cured immediately after mixing (20 seconds, 850mW/cm2) served as a reference. The amount of remaining C=C bonds (%RDB) was measured on the bottom specimen surfaces using ATR-FTIR spectroscopy. One-way ANOVA and multiple comparison tests were used to evaluate the statistically significant differences (α=0.05).
  
  
  RESULTS
  Polymerization mode had a strong effect on the polymerization efficacy of the DCB materials (p<0.0001). The control materials (CN, CP) performed better than the DCB materials (p<0.0001), except for LX in the LC mode. LX and MC showed better SC conversion during the initial 20-minute period. After 60 minutes, the %RDB values of CM were still above 60%, whereas in CD and LX, they reached the level of LC specimens.
  
  
  CONCLUSIONS
  The LC initiation mechanism of the DCB materials that were tested resulted in better C=C conversion when compared to their native SC mechanisms. The SC and LC control materials performed better than the DCB materials, with the exception of LX in the LC mode.
authors.affiliation: National and Kapodistrian University of Athens, Department of Operative Dentistry, Athens, Greece. nikos.kournetas@gmail.com
authors.forename: N
authors.initials: N
authors.lastname: Kournetas
authors.forename: I
authors.initials: I
authors.lastname: Tzoutzas
authors.forename: G
authors.initials: G
authors.lastname: Eliades
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D058105:Polymerization; D011176:Post and Core Technique; D055116:Self-Curing of Dental Resins; D018709:Statistics, Nonparametric
chemical_list: D003188:Composite Resins; D008768:Methylmethacrylates