Characterization of Ti-Zr and Ti-Nb-Zr Experimental Alloys for Dental Implants

Objectives: The increased failure of commercially pure titanium (cpTi) implants has emerged the development of titanium (Ti) alloys to manufacture dental implants. This study investigated the structural, mechanical, chemical and electrochemical properties of experimental Ti alloys with the addition of zirconium (Zr) and niobium (Nb).
Methods: Alloys with the following composition (wt%) were developed: Ti5Zr, Ti10Zr, Ti35Nb5Zr and Ti35Nb10Zr (n=5). CpTi and Ti alloy with aluminium (Al) and vanadium (V) (Ti6Al4V) were used as controls. The Ti discs (10 mm in diameter and 2 mm in thickness) were characterized by microstructural analysis, surface roughness, Vicker’s microhardness, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and surface free energy. For the electrochemical assay, standard tests such as open circuit potential (3,600 sec), electrochemical impedance spectroscopy (frequency ranging from 100 KHz to 5 mHz), and potentiodynamic tests (-0.8 V to 1.8 V and 2 mV/sec scan rate) were conducted in simulated body fluid (pH 7.4) using a potentiostat with a 3-electrode system. Data were analyzed by one-way ANOVA and Tukey HSD test (α=.05).
Results: CpTi and TiZr alloys were characterized as α type, Ti6Al4V and Ti35Nb5Zr were α+β type while Ti35Nb10Zr was β type. Increased microhardness values were noted for TiZr alloys (P<.05) while Nb addition reduced the microhardness of ternary alloys (P<.05). Experimental alloys exhibited lower roughness values and similar surface free energy when compared to controls (P<.05). Higher values of polarization resistance and lower values of capacitance were noted for TiZr alloys (P<.05). The corrosion current density and corrosion rate were the lowest for binary TiZr alloys (P<.05). The incorporation of Nb did not improve the electrochemical behavior of Ti (P>.05).
Conclusions: Binary Ti alloys containing Zr are promising candidates for the manufacture of dental implants.