Evaluation of the effect of different beverages on the mechanical properties of orthodontic arch wires

Purpose: This study was conducted to evaluate the effect of different beverages on surface microhardness, modulus of elasticity and flexural strength of orthodontic archwires.
Materials and Methods: Four orthodontic archwires (stainless steel, NiTi, copper NiTi and Teflon-coated NiTi) were used. They were immersed in three different solutions (Artificial saliva, tea and Coca Cola) for fourweeks. For mechanical properties assessment, the specimens were classified mainly intofour groups (90 specimens each) according to the archwire type. Each group was further subdivided into 3 subgroups (30 specimens arch) according to the used solution. Each subgroup had been divided into three divisions (10 specimens each) according to the test parameter (surface microhardness, modulus of elasticity, flexural strength). Surface microhardness was evaluated using Vickers hardness tester. While modulus of elasticity and flexural strength were measured by subjecting the archwires specimens to the three point bending test using a universal testing machine. Means and standard deviations were calculated for all tests. The data was analyzed and compared using two-way ANOVA analysis and Least Significant Difference (LSD) test (p < 0.05). Results: Artificial saliva significantly decreased the surface microhardness of St. St. and Teflon-coated NiTi archwires and significantly decreased the modulus of elasticity of NiTi, CuNiTi, St.St. archwires. Tea and Coca Cola significantly decreased the surface microhardness of CuNiTi, St. St. and Teflon-coated NiTi archwires and significantly decreased the modulus of elasticity of all archwire specimens. Two-way ANOVA results revealed significant difference among the tested groups (p < 0.001). Conclusions: Tea and Coca Cola potentially would contribute to the change in the mechanical properties of orthodontic archwires leading to prolonged orthodontic treatment.