Further, the effect of implant particles on other cell types within the oral and systemic environments should not be overlooked. Although the health hazards of FPs and NPs are relatively less well established, literature in the fields of toxicology does indicate a glimpse of possible toxicity that should compel clinicians to carefully weigh the possible adverse human health effects. Lastly, “impurities” have been reported in titanium based implant materials, for example, up to 0.5 wt% iron (Fe) in commercial pure titanium (grade 1, 2 and 4) and 0.013 wt% nickel (Ni) (grade 1 and 2). While these trace metals may not present health risk in a whole implant, ions and particles released as a result of corrosion and/or mechanical intervention such as implantoplasty have been reported to cause adverse allergic reactions in humans. There is no current consensus agreement on the risk of particles released from Ti; however, it would be prudent for clinicians to carefully evaluate the materials used and to consider the potential risks of the individual constituents of any alloy, as indicated in this study.

In the present study, the release of nano and fine particles from both commercially pure grade 4 titanium and grade 5 Ti-6Al-4 V alloy implants following implantoplasty procedure was reported. Exposure to grade 5 implant particles resulted in significantly reduced cell viability compared to exposure to grade 4 particles. One of the major challenges facing implant dentistry is the lack of information on the possible adverse health effects caused by the exposure to these nano-sized particles. Authors acknowledge that it is inaccurate to directly extrapolate the current findings into human subjects in clinical settings. However, it is probable that the potential toxicity of Ti-6Al-4 V and/or fine implant particles in vivo are also due, at least in part, to the same mechanism presented in the current study. For patient safety, the potential cytotoxicity of Ti-6Al-4 V alloy particles must be considered when used as a material for dental implants. Furthermore, regardless of implant material, the implantoplasty procedure can release nano-sized particles, the full systemic effect of which is not fully understood. Particles have been shown to have local toxic effects; therefore, the authors do not recommend implantoplasty as a safe procedure for the treatment of peri-implantitis.