# Mechanical Behaviour of Orthodontic Auxiliary Photopolymerisable Resins in Simulated Oral Conditions: An In Vitro Study

## TL;DR

This study examines how a photopolymer resin used in clear aligners behaves under different curing times and oral-like conditions.

## Contribution

The study provides new empirical data on the mechanical behavior of Clear-Blokker® under simulated oral conditions.

## Key findings

- Artificial saliva significantly reduces the Young’s modulus of Clear-Blokker® compared to dry storage.
- Curing time (5 s vs. 10 s) does not significantly affect the mechanical properties of the resin.
- Clear-Blokker® shows mechanical properties comparable to clear aligner materials.

## Abstract

Background: The widespread adoption of clear aligners in orthodontic practice has driven the development of biomechanical devices to improve treatment efficiency. The mechanical properties of these materials play a critical role in determining their clinical performance and efficacy. This study investigates the Young’s modulus of Clear-Blokker® (Scheu Dental), a photopolymerisable resin used for the attachment of clear aligner, and evaluates its mechanical behaviour under different curing times (5 s and 10 s) and environmental conditions (dry storage and immersion in artificial saliva at 37 °C). Methods: Forty-eight cylindrical specimens were prepared and subjected to quasistatic compression tests after 14 days. A multi-factorial analysis of variance (ANOVA) at a significance level of 5% was performed to compare the variances. Results: The results showed that samples immersed in artificial saliva had significantly reduced Young’s moduli compared to samples stored in dry conditions (p = 0.0213), while no significant difference was observed between curing times. Conclusions: The results suggest that Clear-Blokker® has mechanical properties comparable to those of clear aligner materials, making it suitable as a biomechanical aid for orthodontic treatment. However, further clinical studies are required to confirm its long-term efficacy in the oral environment.