Formation and detection of titanium release during implant insertion

Introduction: In orthopaedic wear of titanium components of endo-prosthesis is an increasing problem, especially in hip prosthesis. Inflammation and tissue degeneration make surgical revisions risky and unfavourable. As approximately one million dental implants are inserted every year in Germany alone, side-effects like multi-etiological periimplantitis become more fre-quent. This study is motivated by the need to prevent disturbance of osseo-integrative healing of implants after insertion due to phagocytosis of nano-particles. That may cause activation of prolonged tissue inflammation with subsequent higher risk of implant loss or activation of multi-etiological peri-implantitis. Methods: Human donor bone of D1 quality (Os femoris) was cut in appropriate size and 6 Conelog implants (Camlog) of 3,8 mm diameter (3 implants with a microrough surface and 3 of machined surface) together with 6 Thommen implants of 4 mm diameter (3 implants with a microrough surface and 3 of machined surface) were inserted with a maximum torque of 20 Ncm. Afterwards the bone cavity was opened and investigated for titanium wear. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) was used to perform detection of nanoparticles. Statistical analysis was performed using ANOVA. Results: The occurence of titanium was very limited. Therefore, the size of particles could not be measured. Overall 150 sites in 12 implants have been analyzed (average of 12.5 sitesper implant). In total, the measurements of 37 sites produced positive detection of small traces of titanium (0.016–0.364 wt.%). No differences have been found regarding the surface morphology or type of manufacturer. Remarkably there are differences in the sub-groups. There is a statistically significant difference between machined and microrough surfaces in Canelog implants (p = 0.0161). No difference has been found in machined and microrough Thommen implants (p = 0.696). Summary and Conclusion: This unpretentious investigation actually shows that wear of titanium can occur in human bone simply due to implant insertion. Though wear is extremely limited in human donor bone and of little clinical relevance. Further long-term investigations regarding aspects of bio-tribocorrosion in dental implants are needed. The risk of prolonged inflammation during osseointegration is considered to be extremely low and therefore titanium implants are a safe and predictable therapeutic option. Keywords: bio-tribocorrosion, human donor bone, particles, titanium, wear