Effects of Thermoforming and Intraoral Aging on Mechanical Properties of Three Different Commercially Available Orthodontic Aligners: A Prospective Clinical Study
Year: 2026
Type: article
Abstract: The hardness is indicated by the measurement of the resistance to indentation.For instance, research has shown that variations in hardness can significantly affect how well an aligner retains its shape and applies force over time.8,9 Aligners made from materials with a higher modulus of elasticity can deliver the same forces with thinner dimensions, which improves patient acceptance.10 IntroductIonClear aligner therapy (CAT) involves a series of removable aligners, with incremental tooth movements planned by specialized software.1 Each aligner is designed to be worn for 1 or 2 weeks, achieving linear and rotational tooth movements.2 Aligners are typically made from materials, including derivatives of polyvinyl chloride, thermoplastic polyurethanes (TPU), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polypropylene, polycarbonate, and various copolyesters.3 PETG is an amorphous copolyester derived from PET with enhanced transparency, impact strength, and resistance to chemicals, making it ideal for clear aligners and intricate designs, whereas PU is a polymer with excellent elasticity, abrasion resistance, and tear strength, capable of recovering its shape under and after the load.4 These materials must exhibit specific mechanical characteristics to ensure that they can apply adequate forces on the teeth while maintaining patient comfort.5,6 Thermoplastic polymers exhibit varying responses to oral cavity stresses, including mechanical stress from functional movements, thermal stress from thermoforming (TF) and temperature changes, and chemical stress from saliva and beverages.4 The viscoelastic nature of thermoplastic materials leads to deformation under stress, resulting in a gradual alteration of their mechanical properties over time.
Source: World Journal of Dentistry
Authors: Anjusha Divakar, Ravindra K Jain, Arthi Balasubramaniam
Institution: Saveetha University
Language: English
Subfield: Orthodontics
Field: Dentistry
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7127958115