Force degradation study on aligner plates immersed in various solutions.

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Polymer Science

Background:

• Invisible aligners are susceptible to environmental degradation, impacting their mechanical properties.
• The long-term stability of aligner materials in various beverages is crucial for treatment efficacy.

Purpose of the Study:

• To compare the strength changes of three invisible aligner films after immersion in common beverages.
• To evaluate the degradation resistance of PETG, PET, and PU aligner materials.

Main Methods:

• Three aligner types (Duran T-PETG, Biolon-PET, Zendura FLX-PU) were immersed in artificial saliva, coffee, tea, cola, and red wine for up to 7 days.
• Strength was assessed using a three-point bending test.
• Statistical analysis was performed using the independent t-test (P < 0.05).

Main Results:

• Biolon (PET) and Duran T (PETG) films showed significant strength reduction in certain beverages.
• Zendura FLX (PU) exhibited no significant strength difference across all tested conditions due to a waterproof surface layer.
• Strength decay was observed in most aligner films, except for those with thermoplastic polyurethane (TPU) ingredients.

Conclusions:

• Material composition significantly influences the beverage resistance of invisible aligners.
• Thermoplastic polyurethane (TPU) based aligners demonstrate superior stability in common beverages compared to PETG and PET.
• Zendura FLX (PU) is a promising material for invisible aligners due to its resistance to degradation from dietary factors.