Photofunctionalization increases the bioactivity and osteoconductivity of the titanium alloy Ti6Al4V

Effect of Photofunctionalization on Ti6Al4V Screw Stability Placed in Segmental Bone Defects in Rat Femurs

PURPOSE

Ultraviolet-mediated photofunctionalization is a new technology to improve bone and titanium integration. We hypothesized that photofunctionalization would enhance the stability of titanium screws used for segmental bone defects.

MATERIALS AND METHODS

Disks were prepared of a titanium alloy (Ti6Al4V) for an in vitro study to evaluate the attachment, proliferation, and differentiation of osteoblasts. Commercially available Ti6Al4V screws were used in vivo. Segmental bone defects were created in rat femurs as an immediate loading reconstruction model. The defects were reconstructed with commercially available titanium plates and Ti6Al4V screws, with or without photofunctionalization. The screw survival rates and mechanical stability were evaluated at 2 and 4 weeks, and the bone formation around the screws was analyzed.

RESULTS

Osteoblasts showed greater attachment, proliferation, and differentiation on the photofunctionalized Ti6Al4V disks. Photofunctionalized screws had significantly greater survival rates and mechanical stability at 2 and 4 weeks. The bone formation around the photofunctionalized screws was significantly greater than that around the untreated screws at 4 weeks.

CONCLUSIONS

The results of the present study have demonstrated the efficacy of photofunctionalization on enhancing the survival and stability of Ti6Al4V screws under a loaded condition in the reconstruction of segmental defects. This was associated with increased bioactivity and bone formation around the photofunctionalized Ti6Al4V material.

Effect of UV-photofunctionalization on oral bacterial attachment and biofilm formation to titanium implant material

Bacterial biofilm infections remain prevalent reasons for implant failure. Dental implant placement occurs in the oral environment, which harbors a plethora of biofilm-forming bacteria. Due to its trans-mucosal placement, part of the implant structure is exposed to oral cavity and there is no effective measure to prevent bacterial attachment to implant materials. Here, we demonstrated that UV treatment of titanium immediately prior to use (photofunctionalization) affects the ability of human polymicrobial oral biofilm communities to colonize in the presence of salivary and blood components. UV-treatment of machined titanium transformed the surface from hydrophobic to superhydrophilic. UV-treated surfaces exhibited a significant reduction in bacterial attachment as well as subsequent biofilm formation compared to untreated ones, even though overall bacterial viability was not affected. The function of reducing bacterial colonization was maintained on UV-treated titanium that had been stored in a liquid environment before use. Denaturing gradient gel-electrophoresis (DGGE) and DNA sequencing analyses revealed that while bacterial community profiles appeared different between UV-treated and untreated titanium in the initial attachment phase, this difference vanished as biofilm formation progressed. Our findings confirm that UV-photofunctionalization of titanium has a strong potential to improve outcome of implant placement by creating and maintaining antimicrobial surfaces.

The Relationship between Biofilm and Physical-Chemical Properties of Implant Abutment Materials for Successful Dental Implants

The aim of this review was to investigate the relationship between biofilm and peri-implant disease, with an emphasis on the types of implant abutment surfaces. Individuals with periodontal disease typically have a large amount of pathogenic microorganisms in the periodontal pocket. If the individuals lose their teeth, these microorganisms remain viable inside the mouth and can directly influence peri-implant microbiota. Metal implants offer a suitable solution, but similarly, these remaining bacteria can adhere on abutment implant surfaces, induce peri-implantitis causing potential destruction of the alveolar bone near to the implant threads and cause the subsequent loss of the implant. Studies have demonstrated differences in biofilm formation on dental materials and these variations can be associated with both physical and chemical characteristics of the surfaces. In the case of partially edentulous patients affected by periodontal disease, the ideal type of implant abutments utilized should be one that adheres the least or negligible amounts of periodontopathogenic bacteria. Therefore, it is of clinically relevance to know how the bacteria behave on different types of surfaces in order to develop new materials and/or new types of treatment surfaces, which will reduce or inhibit adhesion of pathogenic microorganisms, and, thus, restrict the use of the abutments with indication propensity for bacterial adhesion.

Mesenchymal stem cell response to UV-photofunctionalized TiO2coated CoCrMo

UV photofunctionalization of TiO₂coated implant surfaces enhanced markers of cell adhesion. This may prove to be advantageous for orthopaedic implants by supporting the colonisation and adhesion of cells capable of facilitating in bone healing.