Patient-Reported Outcomes for Different Orthodontic Thermoplastics Used in Clear Aligners

Overview

Clear aligner therapy is an esthetic orthodontic treatment modality that uses removable thermoplastic trays to correct dental alignment. Different thermoplastic materials, including thermoplastic polyurethane (TPU) and polyethylene terephthalate glycol (PETG), may differ in flexibility and mechanical behavior. These material differences may influence patient-reported outcomes such as pain, mucosal ulceration, tooth sensitivity, tooth mobility, and material-related allergic symptoms. This randomized, double-blind, parallel-group clinical trial will compare patient-reported outcomes in patients treated with clear aligners fabricated from TPU versus PETG. Participants requiring non-extraction clear aligner therapy for mild to moderate crowding will be randomly allocated in a 1:1 ratio to receive aligners fabricated from either PETG or TPU. Outcomes will be recorded at five predefined time points after aligner assignment and wear: T0 before aligner wear, T1 immediately after aligner insertion/wear, T2 at day 1, T3 at day 3, and T4 at day 7.

This is a randomized, double-blind, parallel-group clinical trial conducted at the Department of Orthodontics, Institute of Dentistry, CMH Lahore Medical College, Lahore, Pakistan. Eligible participants will be patients aged 15 to 30 years seeking orthodontic treatment with clear aligners. Patients must have permanent dentition from first molar to first molar, mild to moderate crowding less than 8 mm, and a non-extraction treatment plan. After baseline assessment, participants will be randomized in a 1:1 ratio to receive clear aligners fabricated from PETG or TPU. Randomization will use a computer-generated sequence prepared by an independent statistician. Allocation concealment will be maintained using sealed envelopes by staff not involved in trial assessment. The principal investigator will plan all aligner cases. Linear movements will be limited to 0.25 mm per aligner. Angular movements will be limited to 2 degrees per aligner, except torque, which will be limited to 1 degree per aligner. Each aligner will be worn for 10 days. Patient-reported outcomes will be collected by an operator blinded to the aligner material. Participants will also be blinded to the aligner material. Outcomes include pain on a visual analog scale, ulceration or soft-tissue trauma, tooth sensitivity, tooth mobility, and symptoms suggestive of material-related allergy.