Tissue integration versus bacterial colonization on dental implant materials

Biomaterial implants are frequently used in modern medicine to restore function and form of human anatomy. However, the presence of implanted biomaterials dramatically elevates infection risk. In order to reduce the incidence of infection-associated implant failure, we have applied different materials and surface modifications for tissue integration improvement and inhibiting biofilm formation on dental implants.
At the beginning of this thesis we identified causes as to why dental implants, which are in a bacterial-laden milieu, so often succeed where others, in a near-sterile environment, fail. The major reason is that oral tissues heal fast in the presence of bacteria, and tolerance of the oral immune-system. In order to mimic the oral environment, two in vitro models the peri-operative model, using supra-gingival bacterial strains versus human gingival fibroblast cells, and a late post-operative model involving periodontopathogens versus osteoblast cells have been developed. Results point to a different material for stimulating the formation of a soft tissue seal by the fibroblasts compared to the preservation of osseointegration; the neck of the implant should preferentially be made of smooth titanium, while for osseointegratable parts titanium-zirconium alloy and zirconia variants are to be preferred. The used co-culture studies in this thesis are in line with clinical findings and provide more relevant information than traditional in vitro mono-culture studies addressing solely bacterial or tissue response to biomaterials.