Comparative Evaluation of Mechanical Properties of Cobalt-Chromium, Stainless Steel and β-Titanium Wires: An In Vitro study

AIMOF THE STUDY: To evaluate and compare the mechanical properties of heat treated cobalt-chromium wires with as received stainless steel (SS) and titanium Molybdenum alloy (TMA) wires manufactured by three different companies. METHODS: Nine samples of 0.016″ × 0.022″ inch dimension archwire of SS, TMA and BE from three different companies were chosen. Elgiloy wires were subjected to heat treatment in Furnace at 500oC for 10 minutes. The wire samples were tested in universal testing machine. Each group's specimens were tested at 25°C in 0.5 mm and 1 mm loading, as well as unloading 0.5 mm (from the 1 mm loading) and returning to their original position (zero position). To evaluate mechanical performance in unloading and possible wire deformation, each test was conducted three times with the same wire (A, B, C). RESULTS: The results showed that Blue Elgiloy after heat treatment produced highest force levels on loading and unloading compared to stainless steel and TMA which showed that the mechanical properties of Blue Elgiloy were improved after heat treatment. On comparing the companies of blue Elgiloy wires, all the companies produced similar forces on initial loading and unloading whereas Rocky mountain orthodontics wires produced highest forces after testing for third time indicating higher formability of wires whereas G&H orthodontics wires showed lesser forces after third loading indicating higher shape memory of wires. On comparing the companies of Stainless steel wires, Rocky mountain orthodontics wires showed higher forces on loading and unloading which showed highest stiffness compared to other wires. On comparing the companies of TMA wires, Rocky mountain orthodontics wires showed higher forces on loading and unloading which showed highest stiffness compared to other wires. Wires from Dentaurum and G&H Orthodontics are more resilient than those from Rocky Mountain Orthodontics. CONCLUSION: Heat-treated BE, as received SS and TMA wires of RMO had higher forces and rigidity when compared to other company wires. After heat treatment, Blue Elgiloy wires produced similar force levels to SS wires and increased resistance to deformation during loading and unloading, which could have important clinical implications in the finishing stage of treatment