title: Comparative three-dimensional analysis of initial biofilm formation on three orthodontic bracket materials.
abstract: BACKGROUND
  The purpose of the present study was to investigate and compare early biofilm formation on biomaterials, which are being used in contemporary fixed orthodontic treatment.
  
  
  METHODS
  This study comprised 10 healthy volunteers (5 females and 5 males) with a mean age of 27.3 +-3.7 years. Three slabs of different orthodontic materials (stainless steel, gold and ceramic) were placed in randomized order on a splint in the mandibular molar region. Splints were inserted intraorally for 48 h. Then the slabs were removed from the splints and the biofilms were stained with a two color fluorescence assay for bacterial viability (LIVE/DEAD BacLight-Bacterial Viability Kit 7012, Invitrogen, Mount Waverley, Australia). The quantitative biofilm formation was analyzed by using confocal laser scanning microscopy (CLSM).
  
  
  RESULTS
  The biofilm coverage was 32.7 ± 37.7% on stainless steel surfaces, 59.5 ± 40.0% on gold surfaces and 56.8 ± 43.6% on ceramic surfaces. Statistical analysis showed significant differences in biofilm coverage between the tested materials (p=0.033). The Wilcoxon test demonstrated significantly lower biofilm coverage on steel compared to gold (p=0.011). Biofilm height on stainless steel surfaces was 4.0 ± 7.3 μm, on gold surfaces 6.0 ± 6.6 μm and on ceramic 6.5 ± 6.0 μm. The Friedman test revealed no significant differences between the tested materials (p=0.150). Pairwise comparison demonstrated significant differences between stainless steel and gold (p=0.047).
  
  
  CONCLUSIONS
  Our results indicate that initial biofilm formation seemed to be less on stainless steel surfaces compared with other traditional materials in a short-term observation. Future studies should examine whether there is a difference in long-term biofilm accumulation between stainless steel, gold and ceramic brackets.
authors.affiliation: Center of Dentistry, Oral and Maxillofacial Medicine, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. marc@drdittmer.de.
authors.forename: Marc Philipp
authors.initials: MP
authors.lastname: Dittmer
authors.affiliation: Department of Orthodontics, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. c.fuchslocher@yahoo.de.
authors.forename: Carolina Fuchslocher
authors.initials: CF
authors.lastname: Hellemann
authors.affiliation: Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. grade.sebastian@mh-hannover.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Grade
authors.affiliation: Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. heuer.wieland@mh-hannover.de.
authors.forename: Wieland
authors.initials: W
authors.lastname: Heuer
authors.affiliation: Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. stiesch.meike@mh-hannover.de.
authors.forename: Meike
authors.initials: M
authors.lastname: Stiesch
authors.affiliation: Department of Orthodontics, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. schwestka-polly.rainer@mh-hannover.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Schwestka-Polly
authors.affiliation: Department of Orthodontics, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany. demling.anton@mh-hannover.de.
authors.forename: Anton Phillip
authors.initials: AP
authors.lastname: Demling
mesh_terms: D000328:Adult; D018441:Biofilms / Q000254:growth & development*; D002516:Ceramics / Q000032:analysis; D005260:Female; D006046:Gold / Q000032:analysis; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008422:Materials Testing / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods*; D016910:Orthodontic Brackets / Q000382:microbiology*; D009970:Orthodontics / Q000379:methods; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D013193:Stainless Steel / Q000032:analysis; D013499:Surface Properties; D055815:Young Adult
chemical_list: D013193:Stainless Steel; D006046:Gold