title: Ultrasonic measurement of the effects of adhesive application and power density on the polymerization behavior of core build-up resins.
abstract: OBJECTIVE
  To use ultrasonic measurements to monitor the effects of adhesive application and power density on the polymerization behavior of dual-cured core build-up resins.
  
  
  METHODS
  Ultrasonic measurements were carried out using a pulser-receiver, transducers and an oscilloscope. The core build-up resins were mixed, inserted into a transparent mold and then placed onto a sample stage with or without self-etch adhesive. Power densities of 0 (no light irradiation), 200 and 600 mW/cm(2) were used for curing. The transit time through the core build-up resin disk was divided by the specimen thickness to obtain the longitudinal sound velocity (V).
  
  
  RESULTS
  Light irradiation of the core build-up resins at a power density of 600 mW/cm(2) caused V values to rise to an initial plateau of 1550-1650 m/s, then to rise rapidly to a second plateau of 2800-3200 m/s. The rate of V increase was slower when the resin cements were light-irradiated and became faster when irradiated at a higher power density. There were no significant differences between the groups with or without adhesive.
  
  
  CONCLUSIONS
  The polymerization behavior of the core build-up resins was affected by the power density of the curing unit. The influence of adhesive application differed among the core build-up resins tested.
authors.affiliation: Department of Operative Dentistry, Nihon University School of Dentistry, Kanda-Surugadai, Chiyoda-ku, Tokyo, Japan.
authors.forename: Noriatsu
authors.initials: N
authors.lastname: Sunada
authors.forename: Ryo
authors.initials: R
authors.lastname: Ishii
authors.forename: Koji
authors.initials: K
authors.lastname: Shiratsuchi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Keishi
authors.initials: K
authors.lastname: Tsubota
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Kurokawa
authors.forename: Masashi
authors.initials: M
authors.lastname: Miyazaki
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry / Q000528:radiation effects; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D055117:Curing Lights, Dental; D045662:Dental Etching / Q000379:methods; D008422:Materials Testing; D058105:Polymerization; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry*; D055116:Self-Curing of Dental Resins; D014463:Ultrasonography
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D019279:Resin Cements