Adherence of Porphyromonas gingivalis to modified titanium surfaces

Titanium dental implants provide an important treatment option for replacing missing teeth. Implant failures do however occur and may be promoted by local bacterial infection. Objectives: The aim of this study was to modify the surface roughness and surface free energy of titanium and assess what effect these had on subsequent bacterial adherence. Methods: Sixteen titanium samples of different roughness (34.57-449.42 nm) were prepared by specific polishing procedures. A further 6 samples were chemically altered by argon plasma discharge treatment and immersion in silane solutions to produce different surface hydrophobicities. An in vitro adhesion assay using Porphyromonas gingivalis was then used to assess the effect of modification on bacterial adherence. Results: A significant reduction in adhesion to materials categorised as ‘very smooth' (Ra 34.57 ± 5.79 nm) was evident. This was not evident with ‘smooth' (Ra 155.00 ± 33.36 nm), ‘rough' (Ra 223.24 ± 9.86 nm) or ‘very rough' (Ra 449.42 ± 32.97 nm) surfaces. Changing material surface hydrophobicity was not found to effect bacterial adhesion. Conclusions: Adhesion of P. gingivalis to titanium was inhibited at surface roughness levels below those generally encountered for implant collars/abutments (350 nm). Considerations of these findings may be beneficial in the production of titanium implants in order to reduce bacterial colonisation.