Study of mechanical properties and biocompatibility of tantalum-containing coatings on NiTi orthodontic archwires

The magnetron sputtering method was employed to deposit tantalum-containing coatings on NiTi wire using a pure tantalum metal target under different sputtering conditions. These coatings were deposited on NiTi wires to improve biocompatibility and mechanical behaviour. GI-XRD, FESEM/EDS, MTT assay, nanoindentation, and tensile tests were used to determine how the sputtering atmosphere affects the structure, morphology, biocompatibility, and mechanical properties. Nanoindentation and tensile results showed the highest amount of H.E-1 and H3.E-2 for the coating deposited in a 16.6 vol. % nitrogen, 83.4 vol. % argon atmosphere, which led to high resistance to external forces during stretching and higher mechanical stability. The N2-0.8-300 sample treated in a N2-Ar atmosphere showed the highest cell density due to its resistance to cell-induced stresses and suitable hardness in this sputtering atmosphere. Consequently, the sample deposited in an atmosphere containing 16.6 vol% nitrogen and 83.4 vol% argon is the best candidate for proposed orthodontic archwires in terms of biocompatibility and mechanical behaviour.