Bending strength and hardness comparison of titanium and cobalt–chromium alloys for dentures made by selective laser melting

This in vitro study presents new comparative results for titanium alloy (Ti6Al4V) and cobalt-chromium alloy (Co-Cr) used in removable dental prostheses, including the 3-point bending test and microhardness. For the 3-point bending test, two groups of specimens were designated as group Ti6Al4V and group Co-Cr. For each group, 10 specimens with dimensions of 0.5 × 3 × 25 mm according to ISO 9693-1 were prepared. The Micro-Vickers hardness was measured for 6 specimens of each alloy, with a cylindrical shape (approximately 10 mm in diameter and 3 mm in height). Specimens were prepared with a selective laser melting system for selective laser melting alloys. Different grading of silicon carbide (SiC) papers was used to polish the prepared samples. The surface contaminants were cleaned ultrasonically with acetone and deionized water for at least 10 min. Data were analyzed using Welsh and Mann-Whitney U tests (α = 0.05). No difference in stress values was detected between groups (P = 0.087). However, Ti6Al4V showed higher strain lower modulus of elasticity, and lower microhardness (P < 0.05).