title: Evaluation of surface roughness of different restorative composites after polishing using atomic force microscopy.
abstract: BACKGROUND
  Resin based composites are widely used aesthetic restorative materials in clinical restorative dentistry. The filler size and the percentage of fillers affects smooth surface, clinical durability, aesthetics, better optical properties, compatibility with natural enamel tissue, surface gloss, and preventing the discoloration of the restoration. The finishing and polishing of tooth-coloured restorations are necessary clinical steps for better aesthetics and longevity of restored teeth.
  
  
  OBJECTIVE
  In this study nano composites were chosen, because these contain nano particles which provide better overall composites features, including the quality of polished surface. The aim of this study was to evaluate the surface roughness of different newer posterior composites.
  
  
  METHODS
  Five commercially available posterior restorative composite were tested in this study. All the specimens were polished with shofu multi step polishing system. After polishing the samples were all analyzed by atomic force microscopy which is used to study surface topography and surface morphology of materials.
  
  
  RESULTS
  The values of surface roughness of each specimen were statistically analyzed using Kruskal Wallis ANOVA, and Pair wise comparisons by Mann-Whitney U test setting the statistical significance at p ≤ 0.05.
  
  
  CONCLUSIONS
  Tetric Evo Ceram, Z350 exhibited less surface roughness compared to Ever X, Clearfil Majesty and Sure fil SDR. There was no statistical difference between groups regarding surface rough ness between groups.
authors.affiliation: Department of Conservative Dentistry and Endodontics, M. M. College of Dental Sciences and Research, Mullana, Ambala, Haryana, India.
authors.forename: C Meena
authors.initials: CM
authors.lastname: Kumari
authors.affiliation: Department of Pedodontia, Jaipur Dental College, Jaipur, Rajasthan, India.
authors.forename: K Manohar
authors.initials: KM
authors.lastname: Bhat
authors.affiliation: Department of Conservative Dentistry and Endodontics, M. M. College of Dental Sciences and Research, Mullana, Ambala, Haryana, India.
authors.forename: Rahul
authors.initials: R
authors.lastname: Bansal
keywords: AFM; Composite finishing and polishing; Nano composites; Surface roughness