The Annealing Effects on the Modulus of Elasticity Properties of Different Varieties of Orthodontic Wires: An in vitro Study

Abstract

Aim and Objectives: The main purpose of this study was to define the outcome of annealing on the modulus of elasticity of Heat-activated nitinol, Super elastic nitinol, Stainless Steel, Beta -titanium (TMA), and Cooper nitinol wires. Specific points were tested beside the wire to define how distant from the annealed ends the modulus of elasticity of the wires was affected. Methods: Seventy-Five orthodontic wires consisting of Five groups of Heat Activated Nitinol, Super Elastic Nitinol, and SS/TMA/Copper Nitinol were utilized for this in vitro study. The wires measurement and markings were done by 5mm, and all the wires were sectioned into 33.00 mm.  The gas torch was used to heat the wires until the first 13.00mm wires were seen red hot. We contended load-deflection tests using an Instron®  testing machine at 5mm distances from the end of the wire where annealing is performed and then determining variation in modulus of elasticity. Results: Two-way ANOVA test was done, and the results showed. Concluded that there were significant differences in the change in modulus of elasticity among the parts of the wires in the annealed segment. Stainless Steel wire had the highest primary elastic modulus, Beta Titanium (TMA) wire, Heat Activated Nitinol, Super Elastic Nitinol, and Heat-activated Nitinol had the lowest modulus of elasticity in the Annealed section of wire 8.0/13.0/18.0/23.0mm. Conclusion: There were significant variances in the change in modulus of elasticity among the portions of the wires in the annealed segment. The parts were 5mm and 10mm further from the annealed section. The difference in elastic modulus within the annealed area was significantly more significant at 8 mm than at 13mm. There was considerably greater than 18mm and 23mm and 5mm and 10mm past the annealed segment, separately. Stainless steel showed the biggest changes in elastic modulus throughout annealing and breakages of the wire were compared to the other orthodontic wires.