title: Influence of refractive index on optical parameters of experimental resin composites.
abstract: OBJECTIVE
  Color characteristics of the experimental resin composites were determined to know the influence of different refractive index (RI) on optical parameters.
  
  
  METHODS
  Four experimental light-cured resin composites of the same shade but with different RI were used. The colorimetric values of the specimens were measured against black and white backgrounds using spectrophotometry. The results were converted to CIE L*a*b* color-space values. The chroma (C*ab), color difference (ΔE), translucency parameter (TP) and opacity (OP, opposite property of TP) values were calculated. Surface gloss (GS) of the specimen was also measured.
  
  
  RESULTS
  The L* coordinate, a* coordinate and ΔE*ab values increased as the difference in RI increased. The OP and GS values increased and the TP values decreased as the refractive-index difference increased. The L* and C*ab values increased as the value of the RI increased. The TP, OP and GS values were highly correlated with the RI value. The TP value decreased and the OP and GS values increased, as the RI value increased.
  
  
  CONCLUSIONS
  Refractive index of resin composites is important when thinking about improving the color appearance of esthetic restorations.
authors.affiliation: Department of Operative Dentistry, Nihon University School of Dentistry, Chiyoda-Ku, Tokyo, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Ota
authors.forename: Susumu
authors.initials: S
authors.lastname: Ando
authors.forename: Hajime
authors.initials: H
authors.lastname: Endo
authors.forename: Yukari
authors.initials: Y
authors.lastname: Ogura
authors.forename: Masashi
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Hosoya
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D055620:Optical Phenomena; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D012031:Refractometry; D012821:Silanes / Q000737:chemistry; D013053:Spectrophotometry; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D011109:Polymethacrylic Acids; D012821:Silanes; C020946:triethylene glycol dimethacrylate; C017492:methacryloxypropyltrimethoxysilane; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate