title: Soft tissue integration versus early biofilm formation on different dental implant materials.
abstract: OBJECTIVE
  Dental implants anchor in bone through a tight fit and osseo-integratable properties of the implant surfaces, while a protective soft tissue seal around the implants neck is needed to prevent bacterial destruction of the bone-implant interface. This tissue seal needs to form in the unsterile, oral environment. We aim to identify surface properties of dental implant materials (titanium, titanium-zirconium alloy and zirconium-oxides) that determine the outcome of this "race-for-the-surface" between human-gingival-fibroblasts and different supra-gingival bacterial strains.
  
  
  METHODS
  Biofilms of three streptococcal species or a Staphylococcus aureus strain were grown in mono-cultures on the different implant materials in a parallel-plate-flow-chamber and their biovolume evaluated using confocal-scanning-laser-microscopy. Similarly, adhesion, spreading and growth of human-gingival-fibroblasts were evaluated. Co-culture experiments with bacteria and human-gingival-fibroblasts were carried out to evaluate tissue interaction with bacterially contaminated implant surfaces. Implant surfaces were characterized by their hydrophobicity, roughness and elemental composition.
  
  
  RESULTS
  Biofilm formation occurred on all implant materials, and neither roughness nor hydrophobicity had a decisive influence on biofilm formation. Zirconium-oxide attracted most biofilm. All implant materials were covered by human-gingival-fibroblasts for 80-90% of their surface areas. Human-gingival-fibroblasts lost the race-for-the-surface against all bacterial strains on nearly all implant materials, except on the smoothest titanium variants.
  
  
  CONCLUSIONS
  Smooth titanium implant surfaces provide the best opportunities for a soft tissue seal to form on bacterially contaminated implant surfaces. This conclusion could only be reached in co-culture studies and coincides with the results from the few clinical studies carried out to this end.
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Orthodontics, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
authors.forename: Bingran
authors.initials: B
authors.lastname: Zhao
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands. Electronic address: h.c.van.der.mei@umcg.nl.
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Guruprakash
authors.initials: G
authors.lastname: Subbiahdoss
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Joop
authors.initials: J
authors.lastname: de Vries
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Minie
authors.initials: M
authors.lastname: Rustema-Abbing
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Kuijer
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.affiliation: University of Groningen and University Medical Center of Groningen, Department of Orthodontics, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
authors.forename: Yijin
authors.initials: Y
authors.lastname: Ren
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms; D015921:Dental Implants; D003764:Dental Materials; D005881:Gingiva / Q000382:microbiology / Q000502:physiology*; D006801:Humans; D016348:Osseointegration; D013211:Staphylococcus aureus / Q000254:growth & development / Q000502:physiology; D013499:Surface Properties
chemical_list: D015921:Dental Implants; D003764:Dental Materials
keywords: Osseo-integratable; Supra-gingival bacteria; Surface roughness; Titanium-zirconium alloy; Zirconia