title: Surface morphology changes of acrylic resins during finishing and polishing phases.
abstract: BACKGROUND
  The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients.
  
  
  OBJECTIVE
  The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases.
  
  
  METHODS
  Thirty discs (10 mm in diameter and 5 mm in length) were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test.
  
  
  RESULTS
  The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness.
  
  
  CONCLUSIONS
  Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs, wood sandpaper, water sandpaper, pumice and low abrasive liquids.
authors.forename: Glaucio
authors.initials: G
authors.lastname: Serra
authors.forename: Liliane Siqueira
authors.initials: LS
authors.lastname: de Morais
authors.forename: Carlos Nelson
authors.initials: CN
authors.lastname: Elias
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007834:Lasers; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016382:Orthodontic Appliance Design; D009968:Orthodontic Appliances, Removable; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D017640:Silicates; D012822:Silicon Dioxide; C005144:pumice
keywords: Acrylic resins; Scanning electron microscopy; Surface properties