Ageing effects on chemical, physical, mechanical, and morphological properties of clear aligners - a systematic review.

Researchers systematically reviewed 95 studies examining how clear aligner materials degrade during use, finding that while chemical composition remains mostly stable, physical and mechanical properties deteriorate significantly—especially with TPU-based aligners and printed variants—with substantial colour changes and force loss occurring.

A plain-English summary of the study's own findings — we don't add our own claims or interpretation. Read the full paper for the complete methods and results, and apply your own clinical judgement.