title: Surface geometry of various nanofiller composites using different polishing systems: A comparative study.
abstract: OBJECTIVE
  This in vitro study assessed the surface quality of three nanoparticle composites with four commercially available polishing systems.
  
  
  METHODS
  A total of 180 specimens (10 × 2 mm) were prepared in metal molds using three nanocomposites, Filtek Z-350 XT, Ceram-X Mono, and Tetric N-Ceram. Sixty specimens of each material were then randomly assigned to five study groups. Control specimens were left untreated and the remaining specimens were subjected to polishing with SpinBrite, CompoMaster, AstroPol, and SofLex polishing systems. Average roughness (Ra) and average ten-point roughness (Rz) were calculated using Perthometer, and the data were analyzed by two-way analysis of variance (ANOVA) and post-hoc Tukey's tests.
  
  
  RESULTS
  For all the materials, the roughest surfaces were observed for control specimens, with no statistically significant differences between the material groups. For Filtek Z-350 XT, the decrease in surface roughness after two-step polishing was insignificant. For Ceram-X, SpinBrite specimens showed similar degree of roughness as control specimens. For Tetric N-Ceram, no significant decrease in roughness was observed after one-step polishing. Two-way ANOVA (interaction of subgroups and groups) did not show a significant association with the outcome.
  
  
  CONCLUSIONS
  For nanofilled composites (Filtek Z-350 XT), the surface roughness decreased with the increase in number of polishing steps, whereas one-step and multi-step polishing procedures produced similar quality of smoothness for nanohybrid composites (Ceram-X, Tetric N-Ceram). Ra and Rz values of surface roughness are a function of type of finishing/polishing only.
authors.affiliation: Department of Conservative Dentistry and Endodontics, I.T.S. Centre for Dental Studies and Research, Delhi-Merrut Road, Ghaziabad, Uttar Pradesh, India.
authors.forename: Vipul
authors.initials: V
authors.lastname: Sapra
authors.affiliation: Department of Conservative Dentistry and Endodontics, I.T.S. Centre for Dental Studies and Research, Delhi-Merrut Road, Ghaziabad, Uttar Pradesh, India.
authors.forename: Sonali
authors.initials: S
authors.lastname: Taneja
authors.affiliation: Department of Conservative Dentistry and Endodontics, I.T.S. Centre for Dental Studies and Research, Delhi-Merrut Road, Ghaziabad, Uttar Pradesh, India.
authors.forename: Mohit
authors.initials: M
authors.lastname: Kumar
keywords: Nanocomposites; profilometry; surface roughness