TiN-coated dental implants: Will the coating last?
For the approval of the TiN-coated dental implant, our customer had to prove that the titanium nitride coating can withstand scratching with pointed instruments. The measurement results were generated in our laboratory in a specially developed worst-case scratch test.
Plaque and tartar are removed during routine dental visits by the dental hygienist with pointed instruments. Patients with dental implants may experience scratching on the implant surface with pointed instruments. On behalf of a well-known implant manufacturer, samples of titanium were used in this study to investigate the consequences of such scratching processes on TiN-coated dental implants.
For this purpose, a worst-case scenario was investigated in which a steel tip of an ultrasonic dental instrument scratched the surface of the coated titanium implant with different forces. The test setup developed in the RMS Foundation consisted of the fixed instrument tip and a rotating disc made of pure titanium in variations with and without coating. The abrasion resistance and the coefficient of friction were determined under different contact forces. The scratch marks were then analysed in three dimensions using white light interferometry.
The study showed that the TiN coating can also be scratched under very high loads and that the scratches penetrate the base material. For clinically relevant loads, however, a significant reduction in the scratch depth and abrasion of the TiN-coated discs compared to the uncoated ones was measured.
This example shows that close collaboration between the implant manufacturer and the external testing laboratory has made it possible to establish an applied product-specific test arrangement. This was used to generate relevant measurement results that were used for the approval of the product.
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