Enhancement of the biocompatibility by surface nitriding of a low-modulus titanium alloy for dental implant applications

Yvan Bedouin (1, 2) , Doina-Margareta Gordin (2) , Pascal Pellen-Mussi (2) , Fabienne Pérez (3) , Sylvie Tricot-Doleux (2) , Cora Vasilescu (4) , Silviu Iulian Drob (4) , Dominique Chauvel-Lebret (1, 2) , Thierry Gloriant (2)

1 CHU Pontchaillou [Rennes]
2 ISCR - Institut des Sciences Chimiques de Rennes
3 CHU Nantes - Centre hospitalier universitaire de Nantes
4 ICF - Institute of Physical Chemistry “Ilie Murgulescu” Romanian Academy

To enhance their longevity, dental implants must be highly biocompatible and must have a low elastic modulus close to that of the bone. They must also possess a high superficial hardness and a high corrosion resistance. For these reasons, a recently developed low-modulus Ti-27Nb alloy with nontoxic elements was treated by gas nitriding at high temperature in this study. A very thin nitrided layer of 0.5 μm in thickness followed by an enriched nitrogen zone was observed. Consequently, a very high hardness evaluated at about 1800 HV was obtained in surface, which represents an increase of 4-5 times the hardness of the non-nitrided alloy. This superficial hardness was experimentally observed to decrease up to 800 nm in depth from the surface to the core. The low modulus of Ti-27Nb (evaluated at 55 GPa, which is twice lower than the commercially pure titanium) was not affected by the surface nitriding treatment. A better corrosion resistance was observed and a significant decrease in ion release rates for the nitrided alloy (ion release of 1.41 ng/cm compared to the 163.58 ng/cm obtained for the commercially pure titanium at pH = 7.48 in artificial Carter-Brugirard saliva). The cytocompatibility was not compromised and the cell viability performed on human osteoblasts, fibroblastic cells, and epithelial cells was enhanced on the nitrided surface in comparison with the non-nitrided surface. These combined properties make the nitrided Ti-27Nb alloy a good candidate for dental implant applications.

Keywords: low modulus; superficial hardness; corrosion resistance; biocompatibility; surface nitriding; titanium alloy

Domains: Chemical Sciences; Life Sciences [q-bio]; Biotechnology

Yvan Bedouin, Doina-Margareta Gordin, Pascal Pellen-Mussi, Fabienne Pérez, Sylvie Tricot-Doleux, et al.. Enhancement of the biocompatibility by surface nitriding of a low-modulus titanium alloy for dental implant applications. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2019, 107 (5), pp.1483-1490. ⟨10.1002/jbm.b.34240⟩. ⟨hal-01903314⟩