title: Bacterial adhesion on direct and indirect dental restorative composite resins: An in vitro study on a natural biofilm.
abstract: BACKGROUND
  Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to determine the affinity of bacterial biofilm to dental restorative composite resins placed directly and indirectly.
  
  
  METHODS
  Five direct composite resins for restorations (Venus Diamond, Adonis, Optifil, Enamel Plus HRi, Clearfil Majesty Esthetic) and 3 indirect composite resins (Gradia, Estenia, Signum) were selected. The materials were incubated in unstimulated whole saliva for 1 day. The biofilms grown were collected and their bacterial cells counted. In parallel, the composite resin surface morphology was analyzed with atomic force microscopy. Both bacterial cell count and surface topography parameters were subjected to statistical analysis (α=.05).
  
  
  RESULTS
  Indirect composite resins showed significantly lower levels than direct composite resins for bacterial cell adhesion, (P<.001). No significant differences were observed within the direct composite resins (P>.05). However, within the indirect composite resins a significantly lower level was found for Gradia than Estenia or Signum (P<.01). A partial correlation was observed between composite resin roughness and bacterial adhesion when the second and particularly the third-order statistical moments of the composite resin height distributions were considered.
  
  
  CONCLUSIONS
  Indirect dental restorative composite resins were found to be less prone to biofilm adhesion than direct composite resins. A correlation of bacterial adhesion to surface morphology exists that is described by kurtosis; thus, advanced data analysis is required to discover possible insights into the biologic effects of morphology.
authors.affiliation: Research Associate, Department of Surgical, Medical, Molecular Pathology and Critical Area, University of Pisa, Pisa, Italy; and Tuscan Dental Institute, Lido di Camaiore, Pisa, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Derchi
authors.affiliation: Research Associate, Department of Surgical, Medical, Molecular Pathology and Critical Area, University of Pisa, Pisa, Italy; and Tuscan Dental Institute, Lido di Camaiore, Pisa, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Vano
authors.affiliation: Associate Professor, Department of Surgical, Medical, Molecular Pathology and Critical Area, University of Pisa, Pisa, Italy; and Tuscan Dental Institute, Lido di Camaiore, Pisa, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Barone
authors.affiliation: Professor, Department of Surgical, Medical, Molecular Pathology and Critical Area, University of Pisa, Pisa, Italy; and Tuscan Dental Institute, Lido di Camaiore, Pisa, Italy.
authors.forename: Ugo
authors.initials: U
authors.lastname: Covani
authors.affiliation: Director, Nanophysics Department, Italian Institute of Technology, Genova, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Diaspro
authors.affiliation: Research Technologist, Nanophysics Department, Italian Institute of Technology, Genova, Italy. Electronic address: marco.salerno@iit.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Salerno
mesh_terms: D031843:Adonis; D001422:Bacterial Adhesion; D018441:Biofilms; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000379:methods*; D066298:In Vitro Techniques; D008422:Materials Testing; D008689:Methacrylates; D011140:Polyurethanes; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C470230:Gradia; D008689:Methacrylates; D011140:Polyurethanes; C000612968:Signum Ceramis; C488393:Venus (composite resin); C541508:clearfil majesty; C091839:urethanetrimethacrylate