title: Effect of surface roughness on stain resistance of dental resin composites.
abstract: BACKGROUND
  Surface quality of dental restorations is one of the important factors that determine the success of the restoration. Unfortunately, exterior discoloration is still a problem for dental resin composites.
  
  
  OBJECTIVE
  The purpose of the study was to investigate the influential factors on stain resistance of dental resin composites.
  
  
  METHODS
  Filtek Supreme (nanocomposite), Filtek A110 (microfilled composite), Filtek Z250 (microhybrid composite), and Filtek P60 (microhybrid composite) (all products from 3M ESPE, St. Paul, MN, USA) were tested. Thirty-six specimens per material were prepared and randomly assigned to 6 groups. The specimens in 5 groups were polished against 1,000-, 1,200-, 1,500-, 2,000-, and 2,500-grit sandpaper, respectively. The specimens in a sixth group were polished with 2,500-grit or 1,200-grit sandpaper and used as controls. Surface roughness (Ra) and gloss of the specimens were measured with a profilometer and a glossmeter, respectively. Specimens were immersed in a coffee solution (control group in distilled water) and kept in a 37 degrees C incubator. Color was measured by a spectrophotometer at baseline, 3 days, 7 days, and 14 days, and color change (DeltaE*(ab)) was calculated.
  
  
  RESULTS
  Coffee, material, Ra, and the interaction of material x Ra had statistically significant influences on the stain resistance of the dental composites tested. For most materials in coffee solution, time squared and Ra had significant effects on the discoloration.
  
  
  CONCLUSIONS
  Coffee had a significant influence on discoloration of the dental resin composite materials tested. The different composites behaved differently in coffee solution. Discoloration increased as Ra increased for the composites tested, except with Filtek A110. The discoloration process was accelerated with time.
authors.affiliation: Department of Restorative Dentistry and Biomaterials, Dental Branch, the University of Texas Health Science Center at Houston, Houston, TX 77030-3402, USA. huan.lu@uth.tmc.edu
authors.forename: Huan
authors.initials: H
authors.lastname: Lu
authors.forename: Leslie B
authors.initials: LB
authors.lastname: Roeder
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.forename: John M
authors.initials: JM
authors.lastname: Powers
mesh_terms: D003069:Coffee / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003775:Dental Polishing; D003793:Dental Restoration, Permanent; D006801:Humans; D008422:Materials Testing; D013053:Spectrophotometry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003069:Coffee; D003188:Composite Resins; C452225:Filtek A110 composite resin; C438835:Filtek P60 Composite Resin; C474035:Filtek Supreme; C444701:Filtek Z250