The influence of surface texture and wettability on initial bacterial adhesion on titanium and zirconium oxide dental implants

Torsten Wassmann,Stefan Kreis,Michael Behr,Ralf Buergers

doi:10.1186/s40729-017-0093-3

Abstract

BackgroundThis study aims to investigate bacterial adhesion on different titanium and ceramic implant surfaces, to correlate these findings with surface roughness and surface hydrophobicity, and to define the predominant factor for bacterial adhesion for each material.MethodsZirconia and titanium specimens with different surface textures and wettability (5.0 mm in diameter, 1.0 mm in height) were prepared. Surface roughness was measured by perthometer (Ra) and atomic force microscopy, and hydrophobicity according to contact angles by computerized image analysis. Bacterial suspensions of Streptococcus sanguinis and Staphylococcus epidermidis were incubated for 2 h at 37 °C with ten test specimens for each material group and quantified with fluorescence dye CytoX-Violet and an automated multi-detection reader.ResultsVariations in surface roughness (Ra) did not lead to any differences in adhering S. epidermidis, but higher Ra resulted in increased S. sanguinis adhesion. In contrast, higher bacterial adhesion was observed on hydrophobic surfaces than on hydrophilic surfaces for S. epidermidis but not for S. sanguinis. The potential to adhere S. sanguinis was significantly higher on ceramic surfaces than on titanium surfaces; no such preference could be found for S. epidermidis.ConclusionsBoth surface roughness and wettability may influence the adhesion properties of bacteria on biomaterials; in this context, the predominant factor is dependent on the bacterial species. Wettability was the predominant factor for S. epidermidis and surface texture for S. sanguinis. Zirconia did not show any lower bacterial colonization potential than titanium. Arithmetical mean roughness values Ra (measured by stylus profilometer) are inadequate for describing surface roughness with regard to its potential influence on microbial adhesion.

Highlights

This study aims to investigate bacterial adhesion on different titanium and ceramic implant surfaces, to correlate these findings with surface roughness and surface hydrophobicity, and to define the predominant factor for bacterial adhesion for each material
As soon as implant surfaces are exposed to the human oral cavity, they are immediately colonized by microorganisms [7, 8]
In almost every corresponding investigation, the arithmetical mean roughness roughness values (Ra)—which is measured by stylus profilometer—is used as a parameter to describe implant surface roughness

Summary

Introduction

This study aims to investigate bacterial adhesion on different titanium and ceramic implant surfaces, to correlate these findings with surface roughness and surface hydrophobicity, and to define the predominant factor for bacterial adhesion for each material. Ra values alone may be inadequate to describe “surface roughness” in respect to its potential influence on microbial adhesion [25] For this reason, we applied atomic force microscopy (AFM) for a three-dimensional assessment of the surface topography of the tested materials. The crucial influence of surface wettability on bacterial adhesion is widely accepted, but there is still conflicting evidence if substrata with hydrophobic properties reduce or enhance the quantity of adhering microorganisms [9, 10, 27,28,29,30,31]. No study has yet varied surface roughness and hydrophobicity in well-defined patterns to define the crucial surface factor for different bacterial species

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