Leaching of Different Clear Aligner Systems: An In Vitro Study

Area of Science:

• Material Science
• Analytical Chemistry
• Biomaterials

Background:

• Clear aligners are increasingly popular orthodontic devices.
• Concerns exist regarding potential chemical leaching from these materials.
• Understanding leaching profiles is crucial for patient safety.

Purpose of the Study:

• To compare the leaching of chemical compounds from four distinct clear aligner systems.
• To identify specific chemicals leached under various ethanol-water immersion conditions.
• To evaluate potential differences in leaching among leading clear aligner brands.

Main Methods:

• Four clear aligner systems (Invisalign®, Eon®, SureSmile®, Clarity®) were tested.
• Aligner samples were immersed in ethanol-water solutions of varying concentrations (0-100% ethanol) for two weeks at 37°C.
• Leached substances were analyzed using gas chromatography-mass spectrometry (GC-MS).

Main Results:

• Eleven chemical compounds were detected across the aligner systems.
• Benzene1,3-bis(1,1-dimethylethyl) was found in all systems at higher ethanol concentrations.
• Invisalign® exhibited the lowest leaching, while Eon® showed the highest; no significant inter-system differences were noted overall, except for Eon®.
• No detectable bisphenol-A (BPA) was found in any system.

Conclusions:

• All tested clear aligner systems demonstrated some degree of chemical leaching.
• Invisalign® and Eon® represent the lower and upper bounds of leaching among the evaluated systems.
• The absence of BPA leaching is a positive finding for all tested clear aligners.