title: Plaque formation on surface modified dental implants. An in vitro study.
abstract: Bacterial adhesion on titanium implant surfaces has a strong influence on healing and long-term outcome of dental implants. Parameters like surface roughness and chemical composition of the implant surface were found to have a significant impact on plaque formation. The purpose of this study was to evaluate the influence of two physical hard coatings on bacterial adhesion in comparison with control surfaces of equivalent roughness. Two members of the oral microflora, Streptococcus mutans and Streptococcus sanguis were used. Commercially pure titanium discs were modified using four different surface treatments: physical vapour deposition (PVD) with either titanium nitride (TiN) or zirconium nitride (ZrN), thermal oxidation and structuring with laser radiation. Polished titanium surfaces were used as controls. Surface topography was examined by SEM and estimation of surface roughness was done using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Titanium discs were incubated in the respective bacterial cell suspension for one hour and single colonies formed by adhering bacteria were counted by fluorescence microscopy. Contact angle measurements showed no significant differences between the surface modifications. The surface roughness (Ra) of all surfaces examined was between 0.14 and 1.00 microm. A significant reduction of the number of adherent bacteria was observed on inherently stable titanium hard materials such as TiN and ZrN and thermically oxidated titanium surfaces compared to polished titanium. In conclusion, physical modification of titanium implant surfaces such as coating with TiN or ZrN may reduce bacterial adherence and hence improve clinical results.
authors.affiliation: School of Dental Medicine, Clinic for Restorative Dentistry and Periodontology, University of Kiel, Arnold-Heller-Strasse 16, D-24105 Kiel, Germany. groessner-schreiber@konspar.uni-kiel.de
authors.forename: B
authors.initials: B
authors.lastname: Grössner-Schreiber
authors.forename: M
authors.initials: M
authors.lastname: Griepentrog
authors.forename: I
authors.initials: I
authors.lastname: Haustein
authors.forename: W D
authors.initials: WD
authors.lastname: Müller
authors.forename: K P
authors.initials: KP
authors.lastname: Lange
authors.forename: H
authors.initials: H
authors.lastname: Briedigkeit
authors.forename: U B
authors.initials: UB
authors.lastname: Göbel
mesh_terms: D001422:Bacterial Adhesion; D020099:Coated Materials, Biocompatible; D015921:Dental Implants / Q000382:microbiology*; D003773:Dental Plaque / Q000382:microbiology*; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D010087:Oxides; D012463:Saliva; D018709:Statistics, Nonparametric; D013295:Streptococcus mutans / Q000502:physiology; D013298:Streptococcus sanguis / Q000502:physiology; D013499:Surface Properties; D014025:Titanium / Q000528:radiation effects; D017155:Wettability; D015040:Zirconium
chemical_list: D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D010087:Oxides; C041500:titanium nitride; D015040:Zirconium; D014025:Titanium