title: Light energy transmission through cured resin composite and human dentin.
abstract: OBJECTIVE
  This study determined the amount of light energy transmitted through various densities of cured resin composite and human dentin when 2 different light intensities were used.
  
  
  METHODS
  The maximum light energy (mW/cm2) transmitted through disks (0.46 to 5.85 mm thick) of 7 resin composites and human dentin was measured when either a Standard or a Turbo light guide was attached to a curing light. The effects of the 2 light guides, the specimen thickness, and type of specimen dentin on light energy transmission were determined.
  
  
  RESULTS
  The mean light energy reading at the surface of the specimens was 682.1 mW/cm2 with the Standard light guide and 1,014 mW/cm2 with the Turbo light guide. For all the specimens, there was an exponential decrease in light energy transmitted as the specimen thickness increased. The analysis of covariance showed that the specimen, thickness, and light guide all had a statistically significant effect. Significantly more light energy (about 42%) was transmitted through the specimens when the Turbo light guide was used.
  
  
  CONCLUSIONS
  When the Turbo light guide was used, about 42% more light energy was transmitted through the cured composite specimens. There was an exponential decrease in the light energy transmitted through 7 resin composites and dentin as the specimen thickness increased.
authors.affiliation: Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, Canada. rbprice@is.dal.ca
authors.forename: R B
authors.initials: RB
authors.lastname: Price
authors.forename: D G
authors.initials: DG
authors.lastname: Murphy
authors.forename: T
authors.initials: T
authors.lastname: Dérand
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D003116:Color; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D003804:Dentin / Q000033:anatomy & histology / Q000528:radiation effects*; D004867:Equipment Design; D006801:Humans; D016018:Least-Squares Analysis; D008027:Light; D008029:Lighting / Q000295:instrumentation; D011874:Radiometry; D012542:Scattering, Radiation; D012822:Silicon Dioxide; D013499:Surface Properties; D015040:Zirconium
chemical_list: C406265:Alert composite resin; D003188:Composite Resins; C079764:Pertac hybrid; C099128:Prodigy; C403464:SureFil packable composite; C083568:Z100 composite resin; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium