Analysis, Comparison and Evaluation of the Microhardness and Elasticity of Thermoformed Polyurethane Sheets Used for Treatment with Aligners in Different Brands

Abstract

The present in vitro study aimed to analyze the mechanical (flexural and Microhardness) and optical (color stability) properties of three commercial thermoformed polyurethane sheets used in orthodontics: Essix ACE,® Duran® and Taglus®. These properties, which are crucial for the clinical efficacy of aligners, were evaluated and compared to provide orthodontists with relevant information for selecting the most suitable material for each patient. The results revealed significant differences in mechanical properties between the three brands, suggesting that the choice of material may influence the effectiveness of the treatment. Duran® presented the highest flexural modulus, while Taglus® exhibited the highest Microhardness. Additionally, the color stability of the sheets was evaluated when immersed in different coloring substances, including red wine, orange juice and Fanta®. Red wine produced the greatest color alterations in the materials, a factor to consider for patients. In conclusion, the selection of material for aligner manufacturing should consider not only strength and durability, but also color stability, as well as other factors such as patient comfort. This study provides valuable information on the characteristics of different thermoformed polyurethane sheets, which can be useful for orthodontists to make more informed decisions when selecting the material to manufacture aligners. © 2025 Elsevier B.V., All rights reserved.