Aim: To compare between certain mechanical properties in TPU and PET-G aligner ‎material in terms of tensile strength, hardness, and retention before and after simulated ‎chewing and thermocycling.
Materials and methods: For this study, two types of ‎thermoplastic aligner sheets were used: Memoflex from Aditek orthodontics, (single ‎layered PETG sheets, 0.75 mm thick) and Zendura FLX, (triple layered TPU sheets, 0.76 ‎mm thick). To prepare the samples, a disc shaped model was designed using Autodesk ‎Meshmixer 3.3, then it was 3D printed.
Results: Compared to Zendura FLX aligners, ‎Memoflex aligners had significantly larger median tensile strength, larger median ‎retention force, larger median hardness before (p-value: <0.001) and after simulation.
‎Conclusion: PETG seems to have better mechanical properties when compared to TPU ‎aligners. This can indicate it for use as long term appliances as retainers due to their ‎assumed higher longevity and retentive forces.‎