title: The effect of brushing on surface roughness of denture lining materials.
abstract: OBJECTIVE
  The purpose of this study was to test the effect of brushing on surface roughness of two resilient liners (Luci Sof and Sofreliner) compared with an acrylic resin (QC 20).
  
  
  METHODS
  Twenty specimens of each material were prepared (25 mm x 14 mm x 3 mm). Ten specimens served as controls and were stored in distilled water and not brushed. The remaining ten specimens were subjected to mechanical brushing, using an MSEt plus machine to simulate brushing at a rate of 5.0 strokes per second (30,000 cycles). Surface roughness measurements were recorded before and after brushing. Random samples were analyzed using scanning electron microscope. Data collected were analyzed by a two-way analysis of variance using material and treatment as variables, followed by Tukey's test (alpha= 0.05).
  
  
  RESULTS
  Initial surface roughness of materials indicated that QC 20 was the smoothest (0.13 microm), and Luci Sof the roughest (0.68 mum). Sofreliner had an intermediate value (0.31 microm). All materials were significantly different. Mechanical brushing significantly increased surface roughness in all the materials. Although there was no statistical difference between QC 20 and Luci Sof after mechanical brushing (0.88 and 1.00 microm, respectively), both differed significantly from Sofreliner (7.74 microm).
  
  
  CONCLUSIONS
  The two resilient liners and the acrylic resin became rougher, to a greater or lesser extent, when subjected to mechanical brushing.
authors.affiliation: Department of Prosthodontics and Periodontology, Dental School of Piracicaba, State University of Campinas, Av. Limeira 801, Piracicaba, São Paulo, CEP 13414-018, Brazil.
authors.forename: Luciana Valadares
authors.initials: LV
authors.lastname: Oliveira
authors.forename: Marcelo Ferraz
authors.initials: MF
authors.lastname: Mesquita
authors.forename: Guilherme Elias Pessanha
authors.initials: GE
authors.lastname: Henriques
authors.forename: Rafael Leonardo Xediek
authors.initials: RL
authors.lastname: Consani
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003822:Denture Liners; D013499:Surface Properties; D014099:Toothbrushing / Q000009:adverse effects*
chemical_list: D000180:Acrylic Resins