title: Light transmission on dental resin composites.
abstract: OBJECTIVE
  The purposes of this study was: (1) to examine the light transmittance characteristics of two light-cured resin composites, for different thickness, (2) to correlate the light transmittance through the resin composites and the filler contents, and (3) to determine the penetration depth of the light as a function of the wavelength.
  
  
  METHODS
  Two resin composites (Filtek Z250, shade A2 and Filtek Supreme XT, shade A2E) were used. Specimens of six different thicknesses (0.15, 0.25, 0.30, 0.36, 0.47 and 0.75 mm) were prepared (n=3). The transmittance at wavelengths from 400 to 800 nm was measured using a UV-visible spectrophotometer, before and after light polymerization.
  
  
  CONCLUSIONS
  Significant differences were found in the wavelength dependence of transmittance between the two materials, and between the unpolymerized and polymerized stages of each resin composite. At lower wavelengths, the light transmittance of the Filtek Supreme XT resin composite was lower than the Filtek Z250. At the higher wavelengths, however, Filtek Supreme XT presented higher light transmittance. For both resin composites, the penetration depth was higher after polymerization. However, Filtek Supreme XT showed a higher gain in transmittance at the 0.15 mm thickness. The difference in light transmittance characteristics of the resin composites may affect their depth of polymerization.
authors: Faculdade de Odontologia, Universidade do Estado do Rio de Janeiro, Boulevard 28 de Setembro, 157, Vila Isabel, Rio de Janeiro 20.0000, Brazil.
authors: G B
authors: GB
authors: dos Santos
authors: R V Monte
authors: RV
authors: Alto
authors: H R Sampaio
authors: HR
authors: Filho
authors: E M
authors: EM
authors: da Silva
authors: C E
authors: CE
authors: Fellows
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D006801:Humans; D008027:Light; D008029:Lighting / Q000295:instrumentation; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry / Q000528:radiation effects; D055095:Optics and Photonics; D010316:Particle Size; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D012822:Silicon Dioxide / Q000737:chemistry / Q000528:radiation effects; D013053:Spectrophotometry; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry / Q000528:radiation effects
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C474035:Filtek Supreme; C444701:Filtek Z250; D011108:Polymers; D012822:Silicon Dioxide; D015040:Zirconium; C028541:zirconium oxide