title: Biofilm formation on composite resins for dental restorations: an in situ study on the effect of chlorhexidine mouthrinses.
abstract: OBJECTIVE
  Biofilm formation on the surface of dental restorative materials by oral bacteria is considered an important step in the development of secondary caries. The aim of this study was to evaluate the in situ effect of a chlorhexidine (CHX)-containing mouthrinse on the biofilm formation occurring on the surface of human enamel and of two resin-based commercially available materials: a silorane-based material (Filtek Silorane®) and a methacrylate-based material (Filtek Supreme XT®).
  
  
  METHODS
  53 disks were obtained for each of the two composites and 37 disks for enamel. The surface was characterized by determining the surface roughness and the surface free energy of 5 samples for each of the three materials tested, then the remaining samples were mounted on splints worn by 16 volunteers. The participants were randomly divided into two groups: an experimental group that used 0.12% CHX-based mouthrinse and a control group that used a placebo mouthrinse. Biofilm formation on the different surfaces after a 24 h period was assessed using MTT assay.
  
  
  RESULTS
  The two composites in the group treated with the placebo mouthrinse showed a similar biofilm formation, which was significantly higher than that occurring on enamel surfaces. The CHX-based mouthrinse significantly reduced biofilm formation on the surfaces of the two resin-based materials when compared with the placebo mouthrinse. The reduction was particularly relevant on the Filtek Silorane surfaces.
  
  
  CONCLUSIONS
  The new silorane-based material seems to interact with CHX in a promising way from the point of view of biofilm formation control.
authors.affiliation: Department of Health Sciences, University of Milan, Milan, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Brambilla
authors.forename: Andrei
authors.initials: A
authors.lastname: Ionescu
authors.forename: Massimo
authors.initials: M
authors.lastname: Gagliani
authors.forename: Andrea
authors.initials: A
authors.lastname: Cochis
authors.forename: Carla Renata
authors.initials: CR
authors.lastname: Arciola
authors.forename: Lia
authors.initials: L
authors.lastname: Rimondini
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage*; D058491:Bacterial Load; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002710:Chlorhexidine / Q000008:administration & dosage*; D003188:Composite Resins / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D009067:Mouthwashes / Q000008:administration & dosage*; D062047:Silorane Resins / Q000009:adverse effects*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000891:Anti-Infective Agents, Local; D003188:Composite Resins; C474035:Filtek Supreme; D009067:Mouthwashes; D062047:Silorane Resins; C555513:silorane composite resin; D002710:Chlorhexidine