title: Template assisted surface microstructuring of flowable dental composites and its effect on microbial adhesion properties.
abstract: OBJECTIVE
  Despite their various advantages, such as good esthetic properties, absence of mercury and adhesive bonding to teeth, modern dental composites still have some drawbacks, e.g., a relatively high rate of secondary caries on teeth filled with composite materials. Recent research suggests that microstructured biomaterials surfaces may reduce microbial adhesion to materials due to unfavorable physical material-microbe interactions. The objectives of this study were, therefore, to test the hypotheses that (i) different surface microstructures can be created on composites by a novel straightforward approach potentially suitable for clinical application and (ii) that these surface structures have a statistically significant effect on microbial adhesion properties.
  
  
  METHODS
  Six different dental composites were initially tested for their suitability for microstructuring by polydimethylsiloxane (PDMS) templates. Each composite was light-cured between a glass slide and a microstructured PDMS template. The nano-hybrid composite Grandio Flow was the only tested composite with satisfying structurability, and was therefore used for the bacterial adhesion tests. Composites samples were structured with four different microstructures (flat, cubes, linear trapezoid structures, flat pyramids) and incubated for 4h in centrifuged saliva. The bacterial adherence was then characterized by colony forming units (CFUs) and scanning electron microscopy (SEM).
  
  
  RESULTS
  All four microstructures were successfully transferred from the PDMS templates to the composite Grandio Flow. The CFU-test as well as the quantitative analysis of the SEM images showed the lowest bacterial adhesion on the flat composite samples. The highest bacterial adhesion was observed on the composite samples with linear trapezoid structures, followed by flat pyramids and cubes. The microstructure of dental composite surfaces statistically significantly influenced the adhesion of oral bacteria.
  
  
  CONCLUSIONS
  Modifying the composite surface structure may be a clinically suitable approach to control the microbial adhesion and thus, to reduce the risk of secondary caries at dental composite restorations. Smaller composite surface structures may be useful for accomplishing this.
authors.affiliation: Department of Conservative Dentistry, University Hospital Jena, Friedrich Schiller University, An der alten Post 4, D-07743 Jena, Germany.
authors.forename: Nadja
authors.initials: N
authors.lastname: Frenzel
authors.affiliation: Otto Schott Institute of Materials Research, Faculty of Physics and Astronomy, Friedrich Schiller University, Löbdergraben 32, D-07743 Jena, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Maenz
authors.affiliation: Otto Schott Institute of Materials Research, Faculty of Physics and Astronomy, Friedrich Schiller University, Löbdergraben 32, D-07743 Jena, Germany.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Sanz Beltrán
authors.affiliation: Department of Conservative Dentistry, University Hospital Jena, Friedrich Schiller University, An der alten Post 4, D-07743 Jena, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Völpel
authors.affiliation: Department of Conservative Dentistry, University Hospital Jena, Friedrich Schiller University, An der alten Post 4, D-07743 Jena, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Heyder
authors.affiliation: Department of Conservative Dentistry, University Hospital Jena, Friedrich Schiller University, An der alten Post 4, D-07743 Jena, Germany.
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Sigusch
authors.affiliation: Otto Schott Institute of Materials Research, Faculty of Physics and Astronomy, Friedrich Schiller University, Löbdergraben 32, D-07743 Jena, Germany; Jena School for Microbial Communication (JSMC), Friedrich Schiller University, Jenergasse 8, D-07743 Jena, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lüdecke
authors.affiliation: Otto Schott Institute of Materials Research, Faculty of Physics and Astronomy, Friedrich Schiller University, Löbdergraben 32, D-07743 Jena, Germany; Jena School for Microbial Communication (JSMC), Friedrich Schiller University, Jenergasse 8, D-07743 Jena, Germany. Electronic address: K.Jandt@uni-jena.de.
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Jandt
mesh_terms: D000328:Adult; D001422:Bacterial Adhesion / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects*; D003188:Composite Resins / Q000737:chemistry*; D004245:DMF Index; D003773:Dental Plaque / Q000382:microbiology; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012212:Rheology; D012463:Saliva / Q000737:chemistry; D013234:Stem Cells; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D004129:Dimethylpolysiloxanes; C509998:Grandio; C501891:Tetric EvoCeram; C542517:Venus flow composite resin; C000613961:X-Flow; C541508:clearfil majesty; C111840:flowable hybrid composite; C507210:premise composite resin; C013830:baysilon
keywords: Bacterial adhesion; Dental composites; Microstructuring