title: Effect of surface roughness on the hydrophobicity of a denture-base acrylic resin and Candida albicans colonization.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the effect of surface roughness (roughness average [Ra] μm) on the hydrophobicity of a denture-base acrylic resin and the initial adherence and biofilm formation of Candida albicans (C. albicans).
  
  
  METHODS
  Disk-shaped specimens were divided into six groups: Ra 0.05, Ra 0.2, Ra 0.4, Ra 0.8, Ra 1.5, and Ra 3.0. Water contact angles (WCA) were measured, and the specimens incubated with C. albicans for 90 min (initial adherence, n = 108) or 48 h (biofilm formation, n = 108). Adhered and biofilm cells were evaluated by c.f.u./mL and 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT), and the correlation between the two methods was evaluated. The surface of the specimens and cells (adhered and biofilm) were also analyzed by scanning electron microscopy (SEM).
  
  
  RESULTS
  Groups Ra 0.05 and 3.0 exhibited the lowest (~75°) and the highest (~100°) WCA mean values, respectively. For both initial adherence and biofilm formation, no statistically-significant differences were observed among all groups, as determined by c.f.u./mL and XTT. A positive correlation between these two methods was found. SEM analysis showed the presence of scratches and valleys on the acrylic specimens and densely-packed yeast cells covering the entire surface.
  
  
  CONCLUSIONS
  Roughness significantly increased hydrophobicity (WCA), but had no effect on the number and metabolic activity of adherent and biofilm cells of C. albicans.
authors.affiliation: Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.
authors.forename: Camila C
authors.initials: CC
authors.lastname: de Foggi
authors.affiliation: Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Machado
authors.affiliation: Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.
authors.forename: Camila A
authors.initials: CA
authors.lastname: Zamperini
authors.affiliation: Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.
authors.forename: Darcy
authors.initials: D
authors.lastname: Fernandes
authors.affiliation: Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.
authors.forename: Amanda F
authors.initials: AF
authors.lastname: Wady
authors.affiliation: Araraquara Dental School, Department of Dental Materials and Prosthodontics, São Paulo State University, São Paulo, Brazil.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Vergani
mesh_terms: D000180:Acrylic Resins; D018441:Biofilms; D002176:Candida albicans; D003819:Denture Bases; D057927:Hydrophobic and Hydrophilic Interactions; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins
keywords: Candida albicans; acrylic resin; biofilm; hydrophobicity; surface roughness