Adhesion of Streptococcus mitis and Actinomyces oris in co-culture to machined and anodized titanium surfaces as affected by atmosphere and pH

Abstract

BackgroundWith the rising demand for osseointegrated titanium implants for replacing missing teeth, often in patients with a history of periodontitis, implant-related infections have become an issue of growing concern. Novel methods for treating and preventing implant-associated infections are urgently needed. The aim of this study was to investigate if different pH, atmosphere and surface properties could restrict bacterial adhesion to titanium surfaces used in dental implants.MethodsTitanium discs with machined or anodized (TiUnite™) surface were incubated with a co-culture of Streptococcus mitis and Actinomyces oris (early colonizers of oral surfaces) at pH 5.0, 7.0 and 9.0 at aerobic or anaerobic atmosphere. The adhesion was analysed by counting colony forming (CFU) units on agar and by confocal laser scanning microscopy (CLSM).ResultsThe CFU analysis showed that a pH of 5.0 was found to significantly decrease the adhesion of S. mitis, and an aerobic atmosphere, the adhesion of A. oris. S. mitis was found in significantly less amounts on the anodized surface than the machined surface, while A. oris was found in equal amounts on both surfaces. The CLSM analysis confirmed the results from the CFU count and provided additional information on how the two oral commensal species adhered to the surfaces: mainly in dispersed clusters oriented with the groves of the machined surface and the pores of the anodized surface.ConclusionsBacterial adhesion by S. mitis and A. oris can be restricted by acidic pH and aerobic atmosphere. The anodized surface reduced the adhesion of S. mitis compared to the machined surface; while A. oris adhered equally well to the pores of the anodized surface and to the grooves of the machined surface. It is difficult to transfer these results directly into a clinical situation. However, it is worth further investigating these findings from an in vitro perspective, as well as clinically, to gain more knowledge of the effects acid pH and aerobic atmosphere have on initial bacterial adhesion.

Effect of ultraviolet treatment on bacterial attachment and osteogenic activity to alkali-treated titanium with nanonetwork structures

“…While newly prepared titanium surfaces are acidic, owing to the isoelectric point of TiO 2 (between 5.6 and 6.1), the production of hydroxyl radicals on the TNS surface via the replacement reaction between Na + and H + renders this material basic, 23,24 and basic surface conditions have been shown to promote the attachment of A. oris. 25 A basic titanium surface was previously suggested to have a negative impact on bacterial attachment; 26 however, the results of the present study clearly show that such surfaces yield enhanced colonization of A. oris.…”

The effect of different surface topographies of titanium implants on bacterial biofilm: a systematic review

“…This review did not observe one specific type of titanium surface, which was found to exhibit lower bacterial counts or biofilm mass than the other surfaces. Several studies came to the same conclusion that anodized titanium surfaces exhibited lower bacterial biofilm mass than untreated titanium surfaces [9,18,55] and machined titanium had a lower bacterial biofilm than other types of implant materials (e.g. zirconia, copper) [1,12,29].…”

“…One study stated that the implant surface chemical properties, surface treatment and titanium purity can also influence early bacterial colonization [50]. Actions can be taken to provoke chemical changes in the oral environment to restrict bacterial adhesion after implant placement in order to promote healing [9]. Additionally, the development of in vitro biofilm was more easily influenced by the surface features of the dental implants than biofilm formed by complex communities in the mouth [5].…”

“…Physically textured titanium represented the surfaces with nanostructures comprising thin spears and uniform nanotubular structures [8,32]. The anodized titanium surfaces had a bonelike apatite formation on its surface and a rough homogenous and isotropic structure [9,55]. The laser-modified surfaces had a controlled geometry consisting of micrometrical holes symmetrical in dimension, shape and distribution [19].…”

The influence of nanoporous anodic aluminum oxide on the initial adhesion of Streptococcus mitis and mutans

“…Since AAO surfaces with a pore size of 15 nm have an isoelectric point (iep) of ~6.7, in contrast to pores of 40 nm with a higher iep (~7.9) (Pedimonte et al, ), this lower iep seems to impair the adhesion behavior of S. mitis . Caous et al describe a similar inhibitory effect of a low pH value on S. mitis in anodized titanium materials compared to machined surfaces (Caous, Loevenklev, Faeldt, & Langton, ). Experiments with Escherichia coli on nanoporous solid‐state membranes showed a reduction of protein adsorption with increase of nanoroughness.…”