Intracellular uptake and toxicity of three different Titanium particles.

Introduction: Titanium (Ti) and its alloys are used for implants and other dental materials. In this study, cytotoxicity, DNA damage, cellular uptake and size of three kinds of Ti particles were measured. Methods: Cytotoxicity for Ti microparticles (Ti-MPs, <44. μm), NiTi microparticles (NiTi-MPs, <44. μm), and Ti nanoparticles (Ti-NPs, <100. nm) in periodontal ligament (PDL)-hTERT cells was measured with XTT test. DNA damage was determined with comet assay. Particle size was measured with scanning electron microscope, intracellular uptake was determined with laser scanning confocal microscopy and transmission electron microscopy. Results: The EC50 values of investigated particles were: 2.8mg/ml (Ti-NPs), 41.8mg/ml (NiTi-MPs) and >999mg/ml (Ti-MPs). The Olive Tail Moment (OTM) values at 1/10 EC50 were: 3.2 (Ti-NPs) and 2.2 (NiTi-MPs). An OTM of 2.2 for Ti-MPs was detected at the concentration of 6666μg/ml. Determined sizes of investigated particles were 20-250nm (Ti-NPs), 0.7-90μm (NiTi-MPs) and 0.3-43μm (Ti-MPs). The highest cellular uptake efficiency was observed with Ti-NPs, followed by Ti-MPs and NiTi-MPs. Only Ti-NPs were found in the nucleus. Conclusion: Compared to Ti-MPs and NiTi-MPs, Ti-NPs induced higher cellular uptake efficiency and higher toxic potential in PDL-hTERT cells. Ni in the alloy NiTi induced an increase in the toxic potential compared to Ti-MPs