# Mechanical properties of thermoformed and 3D-printed aligners after cleansing solution exposure: An in vitro study

## TL;DR

This study examines how cleaning solutions affect the mechanical properties of orthodontic aligners made from different materials.

## Contribution

The study provides new insights into the effects of specific cleaning agents on aligner materials.

## Key findings

- Peroxide-based cleaners significantly degrade aligner properties.
- Resin-based aligners show superior resistance to cleaning agents.
- Artificial saliva has minimal impact on mechanical properties.

## Abstract

The impact of common cleaning solutions on the mechanical properties of clear orthodontic aligners made from PET-G, polyurethane and
resin-based materials is of interest. Nanoindentation tests measured elastic modulus, hardness, elastic index and load relaxation after
exposure to Retainer Brite®, Fresh Guard® and artificial saliva. The results showed that peroxide-based cleaners significantly degrade
aligner properties, while Fresh Guard® causes moderate changes and artificial saliva has minimal effects. Resin-based aligners showed
superior chemical stability, making them more resistant to cleaning agents. Thus, mild cleaners are recommended for maintaining aligner
performance.