Comparison of Single-Layer and Triple-Layer TPU MaxFlex Aligners After Intraoral Use

NCT07566533 | Completed DMC

• 2 other identifiers: TPU-ALIGNER-01no identifier
• Study Type: interventional
• Target: 66
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to compare two types of clear orthodontic aligner materials used in dental treatment: single-layer and triple-layer thermoplastic polyurethane (TPU) aligners (MaxFlex). Clear aligners are commonly used to straighten teeth and are preferred for their comfort and aesthetic appearance. Participants will be provided with aligners and instructed to wear them for approximately 22 hours per day for 10 days. The aligners will be collected before use and after the 10-day period. The study will evaluate how the oral environment affects the properties of these materials over time. Laboratory tests will be conducted to measure mechanical properties such as strength, flexibility, and deformation, as well as to examine surface changes under a microscope. The results of this study may help improve the performance and durability of aligners and contribute to better orthodontic treatment outcomes.

Conditions

Clear Aligner Therapy; Malocclusion; Orthodontic Treatment

Keywords

Thermoplastic Polyurethane (TPU); Clear Aligners; MaxFlex Aligners; Intraoral Aging; Scanning Electron Microscopy (SEM)

Outcome Measures

Primary Outcomes (3)

• Effect of Oral Environment on Elastic Modulus of TPU Aligners

  This outcome measures the change in elastic modulus (MPa) of thermoplastic polyurethane (TPU) orthodontic aligners following intraoral exposure. Measurements are obtained using a dynamic mechanical analyzer and compared between single-layer and multilayer TPU aligners at baseline and after two weeks of clinical use to assess changes in stiffness and material integrity.

  Baseline (0 week) and after 2 weeks of intraoral use (minimum 22 hours/day)

• Effect of Oral Environment on Stress Relaxation of TPU Aligners

  This outcome measures the percentage stress relaxation (%) of TPU aligners following intraoral exposure. Stress decay over time is recorded using a dynamic mechanical analyzer and compared between single-layer and multilayer TPU aligners at baseline and after two weeks to evaluate force retention capacity.

  Time Frame: Baseline (0 week) and after 2 weeks of intraoral use (minimum 22 hours/day)

• Effect of Oral Environment on Creep Behavior of TPU Aligners

  This outcome measures creep (% strain) in TPU aligners under constant stress conditions using a dynamic mechanical analyzer. Comparisons are made between single-layer and multilayer TPU aligners at baseline and after two weeks to assess susceptibility to permanent deformation.

  Time Frame: Baseline (0 week) and after 2 weeks of intraoral use (minimum 22 hours/day)

Study Arms (2)

Single-Layer TPU Aligner Group

EXPERIMENTAL

Participants in this group will receive single-layer thermoplastic polyurethane (TPU) MaxFlex aligners. The aligners will be worn intraorally for 10 days for a minimum of 22 hours per day under standardized conditions. Aligners will be collected at baseline and after the wear period for evaluation of mechanical properties and surface morphology.

Device: Single-Layer Thermoplastic Polyurethane Aligner

Triple-Layer TPU Aligner Group

EXPERIMENTAL

Participants in this group will receive triple-layer thermoplastic polyurethane (TPU) MaxFlex aligners consisting of a soft inner layer, a rigid intermediate layer, and a flexible outer layer. The aligners will be worn intraorally for 10 days for a minimum of 22 hours per day. Aligners will be collected at baseline and after use for mechanical and surface analysis.

Device: Triple-Layer Thermoplastic Polyurethane Aligner

Interventions

Single-Layer Thermoplastic Polyurethane Aligner DEVICE

Single-layer thermoplastic polyurethane (TPU) clear aligners fabricated from a homogeneous TPU sheet using thermoforming techniques. These aligners are designed to deliver orthodontic forces for tooth movement. Participants will be instructed to wear the aligners intraorally for 10 days for a minimum of 22 hours per day. The aligners will be evaluated before use and after intraoral exposure to assess changes in mechanical properties and surface morphology.

Single-Layer TPU Aligner Group

Triple-Layer Thermoplastic Polyurethane Aligner DEVICE

Triple-layer thermoplastic polyurethane (TPU) clear aligners composed of a multilayer structure including a soft inner layer, a rigid intermediate layer, and a flexible outer layer. These aligners are fabricated using thermoforming techniques and are designed to provide improved force delivery and adaptability. Participants will wear the aligners intraorally for 10 days for at least 22 hours per day. Pre- and post-use evaluations will be conducted to assess mechanical properties and surface morphology changes.

Triple-Layer TPU Aligner Group

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Patients aged 18-30 years Fully erupted permanent dentition Good periodontal health Patients undergoing orthodontic treatment with clear aligners Mild crowding or spacing requiring labiolingual tooth movement Willingness to wear aligners for at least 22 hours per day Provision of informed consent

You may not qualify if:

• Use of aligners from manufacturers other than study-specific TPU aligners Damaged or fractured aligners Poor compliance (wear time less than 22 hours/day) Presence of parafunctional habits (e.g., bruxism) Hypodontia or partially erupted dentition Cases involving bonded attachments on maxillary incisors Cases requiring rotational movement of maxillary incisors Patients with systemic or oral conditions affecting saliva composition or the oral environment

Sponsors & Collaborators

• Ayub Medical College, Abbottabad: lead

Study Sites (1)

Akhtar Saeed Medical & Dental College

Lahore, Punjab Province, Pakistan

Location

MeSH Terms

Conditions

Malocclusion

Condition Hierarchy (Ancestors)

Tooth Diseases; Stomatognathic Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The investigators performing laboratory analyses, including mechanical testing and surface morphology evaluation, will be blinded to group allocation to minimize assessment bias.
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Doctor

Model Details: Participants will be randomly assigned to one of two parallel groups receiving either single-layer or triple-layer thermoplastic polyurethane (TPU) aligners (MaxFlex). Each participant will use the assigned aligner type for 10 days under standardized conditions (minimum 22 hours per day), after which the aligners will be retrieved for laboratory analysis.

Study Record Dates

• First Submitted: April 19, 2026
• First Posted: May 5, 2026
• Study Start: September 13, 2025
• Primary Completion: March 5, 2026
• Study Completion: March 16, 2026
• Last Updated: May 5, 2026

Record last verified: 2025-09

Locations

PA (1)