Biofunctional properties and electrochemical behavior of loose sintering titanium alloys under simulated oral conditions and acidic dietary habits

Abstract

Commercially pure titanium (cpTi IV) and Ti6Al4V are widely used in dental implants due to their good me- chanical properties and clinical reliability. However, their high elastic modulus may cause biomechanical mismatch with bone, and Ti6Al4V contains potentially cytotoxic elements such as Al and V. Additionally, exposure to acidic carbonated beverages may compromise implant longevity by accelerating corrosion. This study compares the biomechanical (stiffness and strength) and biofunctional (corrosion resistance and bioac- tivity) performance of cpTi IV and Ti6Al4V with a commercial Ti35Nb7Zr5Ta alloy, which features a lower elastic modulus and lacks cytotoxic elements. Although promising, Ti35Nb7Zr5Ta is more costly and requires more complex processing, warranting detailed evaluation. Disc-shaped samples were produced by loose sintering and fully dense processing to assess the influence of porosity. Corrosion behavior was analyzed using open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization in artificial saliva and Coca-Cola at 37 ◦C. Results show superior corrosion resistance for cpTi IV, balanced mechanical–corrosion behavior for Ti6Al4V, and improved biomechanical compatibility and bioactivity for Ti35Nb7Zr5Ta. Porosity and acidic conditions negatively affected passive film stability. These findings support optimization of titanium- based dental and orthopedic implants.