Wear behavior of experimental Ti-5Al and Ti-5Al-5Cu alloys

Objective: This study assessed the wear resistance of experimental Ti-5Al and Ti-5Al-5Cu alloys for possible use in prosthetic teeth. Methods: Ti-5mass%Al and Ti-5mass%Al-5wt%Cu alloys were made with the necessary amounts of elements in an argon arc-melting furnace (MarkIII High Vacuum/Controlled Atmosphere Arc melting System, IVI Corp, MA, USA). Maxillary and mandibular teeth duplicated from artificial first molars (Livdent FB30, GC Dental, Tokyo, Japan) were used as patterns for casting. Each alloy was cast into a mold made of a phosphate-bonded investment material (T-invest, GC Dental) using a gas-pressure casting unit (Autocast HC-III, GC Dental). After sandblasting with 50 µm Al2O3 and chemical treatment with a HNO3/HF solution (Chemipolish, Shofu, Kyoto, Japan), the wear was tested using a two-body wear testing apparatus that simulated chewing function. Wear was assessed as volume loss (mm3) after the test (n=5). The data for these alloys were compared to previously recorded data for CP Ti grade III (CP Ti), Ti-6Al-7Nb (6-7), and Au-Pt (Ohkubo et al., J Prosthodont 11:263-269, 2002). The wear resistance was analyzed by ANOVA/Duncan's test (α=0.05). Results: The results of testing [Mean (SD)] were: CP Ti: 1.89 (0.37), 6-7: 0.89 (0.20), Ti-5Al: 0.38 (0.31), Ti-5Al-5Cu: 0.63 (0.29), and Au-Pt: 0.55 (0.14). Excluding the data for the CP Ti and 6-7, there were no statistical differences among the metals tested (p>0.05). The wear was statistically the highest for CP Ti (p<0.05) and the lowest for the Ti-5Al. Conclusion: The wear behavior of the experimental Ti-5Al and Ti-5Al-5Cu alloys was comparable to that of Au-Pt. This study was partially supported by NIH-NIDCR grant 11787.