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A Comparison Between the Expansion Force Exerted by Thermo-Printed Aligners and 3D Printed Aligners: An In Vitro
Samuele Avolese1,2, Simone Parrini2, Andrea Tancredi Lugas3
1Department of Mechanical and Aerospace Engineering, Polytechnic University of Turin, 10100 Torino, Italy.
Bioengineering (Basel, Switzerland)
|September 27, 2025
Summary
This study compared the forces of 3D printed orthodontic aligners (TC-85 DAC resin) to traditional thermoformed aligners (Smart Track®). The 3D printed aligners generated minimal force for dental arch expansion, unlike the thermoformed ones.
Area of Science:
- Biomaterials Science
- Orthodontics
- Dental Technology
Background:
- Three-dimensional (3D) printing offers potential efficiency gains in orthodontic aligner fabrication compared to traditional methods.
- However, the dimensional fidelity and force delivery of 3D printed aligners require thorough investigation.
- This study evaluates the forces produced by 3D printed aligners using TC-85 DAC resin.
Purpose of the Study:
- To measure and compare the forces exerted by 3D printed aligners (TC-85 DAC resin) with conventional thermoformed aligners (Smart Track®).
- To assess the effectiveness of 3D printed aligners in achieving programmed dental arch expansion movements.
- To investigate the impact of 3D printing technology on the mechanical properties of orthodontic appliances.
Main Methods:
- A patient in transitional mixed dentition underwent virtual setup for upper arch expansion (0.2 mm and 0.4 mm per side).
- Ten Smart Track® aligners and ten 3D printed TC-85 DAC resin aligners were fabricated based on the virtual setup.
- Aligner forces were measured using an ElectroForce® Test Bench within a 37°C thermostatic bath simulating intraoral conditions.
Main Results:
- Smart Track® aligners generated significant expansion forces: +0.2162 N (0.2 mm expansion) and +0.7159 N (0.4 mm expansion).
- TC-85 DAC resin 3D printed aligners produced negligible forces: -0.0034 N (0.2 mm expansion) and +0.0141 N (0.4 mm expansion).
- A notable difference in force delivery was observed between the two aligner types.
Conclusions:
- Thermoformed Smart Track® aligners effectively deliver measurable forces for posterior dental arch expansion.
- Orthodontic aligners fabricated with TC-85 DAC resin exhibit forces close to zero for programmed expansion movements.
- The findings suggest significant differences in the biomechanical performance between 3D printed and thermoformed orthodontic aligners.
Keywords:
3D printed alignersaligner biomechanicsdigital orthodonticsforce measurementmixed dentitionorthodontic expansion
