title: Translucency, opalescence and light transmission characteristics of light-cured resin composites.
abstract: OBJECTIVE
  To evaluate the translucency, opalescence and light transmission characteristics of resin composites with different thicknesses.
  
  
  METHODS
  Disks of three resin composites (Estelite∑, Beautifil II, Clearfil Majesty) of A2 shade were prepared in diameter of 10mm with various thicknesses (0.5mm, 1.0mm and 2.0mm). Color was measured according to CIELAB color scale on a reflection spectrophotometer and a color haze meter, and translucency parameter (TP) and opalescence parameter (OP) were calculated. Using the distribution graphs of transmitted light intensity on a goniophotometer, diffusion factor (DF) as an indicator for a diffuse transmission property and peak gain (G0) for a straight-line transmission property were calculated.
  
  
  RESULTS
  The TP and G0 values significantly decreased in the order: 0.5mm>1.0mm>2.0mm thickness (p<0.05). The OP value increased as the thickness of resin composite increased from 1.0mm to 2.0mm (p<0.05), while was similar for the 0.5mm- and 1.0mm-thick groups. The DF value increased from 0.5mm to 1.0mm, but was similar for the 1.0mm- and 2.0mm-thick groups. There was a significant correlation between TP and DF (R(2)=0.96, p<0.001). On the other hand, there was a weak correlation between OP and DF (R(2)=0.21, p<0.005), however within the values of the 0.5mm-thick group, OP was highly correlated with DF (R(2)=0.84, p<0.001).
  
  
  CONCLUSIONS
  At the 0.5mm thickness, the translucency (TP) and opalescence (OP) of resin composites had a significant correlation with a diffuse transmission property (DF). When more than 1.0mm thickness of resin composites, translucency and opalescence were influenced by the thickness, in which translucency significantly decreased and opalescence significantly increased.
authors.affiliation: Department of Restorative Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Japan. abookofants@yahoo.co.jp
authors.forename: Ayako
authors.initials: A
authors.lastname: Arimoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hosaka
authors.forename: Kozo
authors.initials: K
authors.lastname: Nishimura
authors.forename: Masaomi
authors.initials: M
authors.lastname: Ikeda
authors.forename: Richard M
authors.initials: RM
authors.lastname: Foxton
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D006801:Humans; D008027:Light; D055620:Optical Phenomena; D010783:Photometry; D013053:Spectrophotometry; D013499:Surface Properties
chemical_list: C470433:Beautifil composite resin; D003188:Composite Resins; D003764:Dental Materials; C507124:Estelite sigma; C541508:clearfil majesty; D017438:Bisphenol A-Glycidyl Methacrylate