Timo O. Na ¨ rhi Heidi Leminen Anna Haukioja Eva So ¨ derling Adhesion of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum on bioactive TiO 2 surfaces Authors’ affiliations: Timo O. Na ¨ rhi, Eva So ¨ derling, Department of Prosthetic Dentistry, Institute of Dentistry, University of Turku, Turku, Finland Timo O. Na ¨ rhi, Heidi Leminen, Clinic of Oral Diseases, Turku University Central Hospital, Turku, Finland Anna Haukioja, Eva So ¨ derling, Institute of Dentistry, University of Turku, Turku, Finland and National Institute of Health and Welfare, Helsinki, Finland Timo O. Na ¨ rhi, Eva So ¨ derling, Turku Clinical Biomaterials Centre, Turku, Finland Corresponding author: Timo O. Na ¨ rhi Department of Prosthetic Dentistry, Institute of Dentistry, University of Turku, Turku, Finland Tel.: +35823338295 Fax: +35823338390 e-mail: timo.narhi@utu.fi Key words: biomaterials, material sciences, microbiology, periodontology, soft tissue-implant interactions Abstract Background: Bioactive TiO 2 coatings have been found to enhance fibroblast adhesion and gingival attachment on the titanium surfaces, but no information is available whether the coatings also promote the adhesion of periodontal pathogens. Aim: The purpose of this study was to investigate protein adsorption and the adhesion of Aggregatibacter actinomycetemcomitans (Aa) and Fusobacterium nucleatum (Fn) on bioactive TiO2 surfaces. Materials and methods: Commercially pure titanium discs (diameter 11.0 mm, grade 2) were coated with sol-gel derived bioactive TiO2 coatings (MetAlive, Vivoxid, Turku, Finland) and preincubated in 1.5 ml PBS/diluted serum/diluted saliva at room temperature to mimic the clinical situation after implantation and to allow serum/saliva proteins to adhere on the substrates. Uncoated titanium discs were used as controls. Results: SDS-PAGE revealed similar protein profiles on bioactive and control titanium substrates. No differences were noticed in Aa or Fn adhesion between bioactive and control titanium. However, serum and saliva conditioning diminished Aa adhesion on both surfaces (p<0.001). Conclusion: It can be concluded that bioactive TiO2 coating does not promote adhesion of Aa and Fn. Good bone and soft tissue attachment is an important prerequisite for successful implant therapy. Bone bonding of currently available oral implants is good due to their bone inte- gration promoting surface treatments (Al- brektsson et al. 2003). However, none of the surface modifications of commercially avail- able implants have been able to facilitate direct soft tissue attachment, which would be comparable with the bonding of bone on the implant surfaces. We have recently reported about soft tissue response to sol-gel- derived TiO 2 coatings. This nanoporous sur- face treatment mediates direct fibroblast attachment on different substrates (Areva et al. 2004; Paldan et al., 2008; Meretoja et al. 2010). Bonding between cells and coat- ing is mechanically strong (Paldan et al. 2008; Meretoja et al. 2010). Good peri- implant tissue attachment on coated oral implants has been verified also in clinical conditions in a pre-clinical trial (Rossi et al. 2007) and in a clinical pilot study (Wenner- berg et al. 2011). Serum proteins attach on TiO 2 surface immediately after the coated implant is exposed to blood (Areva et al. 2004). Specific protein adsorption seems to promote wound healing process, which is probably the most important reason for the strong fibroblast adhesion. Microbial colonization on oral implants follows the same pattern as on tooth surfaces (Subramani et al. 2009). In both cases, micro- bial colonization is determined by the forma- tion of acellular salivary pellicle. Thus, in clinical environment, bacterial adhesion and subsequent biofilm development is strongly determined by materials ability to adsorb flu- ids from their surroundings. In the oral environment, implants and implant abutments are exposed to saliva, pla- que, and crevicular fluid, which raise the question whether or not oral microorganisms can attach to TiO 2 -coated implants and increase the risk for peri-implant infections. Therefore, we set out to study the attach- Date: Accepted 19 November 2011 To cite this article: Na ¨ rhi TO, Leminen H, Haukioja A, So ¨ derling E. Adhesion of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum on bioactive TiO2 surfaces. Clin. Oral Impl. Res. 00, 2012, 1–5 doi: 10.1111/j.1600-0501.2011.02399.x © 2012 John Wiley & Sons A/S 1