title: Changes in translucency of resin composites after storage in salivary esterase.
abstract: BACKGROUND
  Dental resin composites are degraded by salivary enzymes, but the enzymatic influence on the translucency of resin composites has not been determined.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the changes in translucency of resin composites after storage in the salivary enzyme esterase (ETE, porcine liver esterase, 400 mU/mL) compared with those in phosphate-buffered saline (PBS).
  
  
  METHODS
  The colors of specimens of three brands of resin composites of various shades were measured after polymerization and polishing (baseline), and after immersion in PBS or ETE for 9 weeks; measurements were determined over white and black backgrounds according to the CIELAB color scale (established by Commission Internationale de l'Eclairage). The final specimen thickness was 1.75 mm. Translucency parameter (TP) was obtained by calculating the color difference between the specimen over a white background and that over a black background. Two-factor, repeated-measures analysis of variance was used to compare differences.
  
  
  RESULTS
  TP values varied among and within different shade designations and also among different brands of resin composites. TP values were significantly changed after immersion in PBS and ETE and were influenced by the brand of resin composites, but they were not influenced differently by the immersion solutions of PBS and ETE (p = .05).
  
  
  CONCLUSIONS
  Translucency of dental resin composites is an important esthetic consideration. Based on the results of this study, the influence of salivary esterase on the changes in translucency of dental resin composites is not significantly different from that of phosphate-buffered saline. Therefore, it can be concluded that the enzymatic effects of saliva do not adversely alter the translucency of dental resin composites.
authors.affiliation: Department of Dental Biomaterials Science, Dental Research Institute, College of Dentistry, Seoul National University, Korea.
authors.forename: Yong-Keun
authors.initials: YK
authors.lastname: Lee
authors.forename: Seung-Heon
authors.initials: SH
authors.lastname: Kim
authors.forename: John M
authors.initials: JM
authors.lastname: Powers
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003116:Color; D003188:Composite Resins; D004950:Esterases; D006801:Humans; D008027:Light; D008099:Liver / Q000201:enzymology; D008422:Materials Testing; D008689:Methacrylates; D012463:Saliva / Q000201:enzymology*; D013552:Swine
chemical_list: D003188:Composite Resins; C474035:Filtek Supreme; D008689:Methacrylates; C485364:Renew composite; C451741:point 4 composite resin; D004950:Esterases