title: Effectiveness of polymerization of a prosthetic composite using three polymerization systems.
abstract: BACKGROUND
  Although properties of laboratory-polymerized composite materials are influenced by the type of polymerizing unit, little information is available regarding the comparison between use of a high-intensity light source and application of secondary heat treatment.
  
  
  OBJECTIVE
  This study examined properties of a prosthetic veneering composite polymerized with 3 polymerizing systems to evaluate the effects of varying polymerization modes on hardness, solubility, and depth of cure.
  
  
  METHODS
  A composite material designed for a prosthetic veneer (Conquest Crown and Bridge) was polymerized using 3 methods: (1) exposure in the proprietary photopolymerizing unit with 2 halogen lamps (Cure-Lite Plus), followed by heating in an oven (Conquest Automatic Curing Unit); (2) exposure in a photopolymerizing unit with a xenon stroboscopic light source (Dentacolor XS); and (3) exposure in a photopolymerizing unit with 2 metal halide lamps (Hyper LII). Knoop hardness, water solubility, and depth of cure were determined for groups of 5 specimens, according to standardized testing methods. Data were compared using analysis of variance and the Duncan new multiple range test (P <.05).
  
  
  RESULTS
  The hardness number generated with the metal halide unit was statistically greater than those produced by the other 2 methods, and material component released into water was minimal when the material was exposed with the metal halide unit (P <.05). Among the 3 photopolymerizing units, the metal halide unit consistently exhibited the greatest depth of cure.
  
  
  CONCLUSIONS
  Certain properties generated with the use of the high-intensity polymerizing unit exceeded those obtained from a proprietary system that requires a postheat treatment.
authors.affiliation: Nagasaki University School of Dentistry, Nagasaki, Japan. t-naomi@net.nagasaki-u.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Tanoue
authors.forename: H
authors.initials: H
authors.lastname: Matsumura
authors.forename: M
authors.initials: M
authors.lastname: Atsuta
mesh_terms: D000704:Analysis of Variance; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003188:Composite Resins / Q000737:chemistry*; D003801:Dental Veneers; D006244:Hardness; D006358:Hot Temperature; D008027:Light; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D018709:Statistics, Nonparametric; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; C092421:Conquest composite resin; D011108:Polymers; D014867:Water