Influence of Post-Processing on the Degree of Conversion and Mechanical Properties of 3D-Printed Polyurethane Aligners

Scientific paper - Original scientific paper

• Author: Luka Šimunović
• Author: Antonija Jurela
• Author: Karlo Sudarević
• Author: Ivana Bačić
• Author: Tatjana Haramina
• Author: Senka Meštrović
• Author's institution: (Zagreb University Hispital Center)
• Author's institution: University of Zagreb; Faculty of Electrical Engineering and Computing
• Author's institution: University of Zagreb; School of Dental Medicine
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Dental Medicine

Abstract (english)

Background: This study explores how different post-processing methods affect the mechanical properties and degree of conversion of 3d-printed polyurethane aligners made from Tera Harz TC-85 resin. Methods: Using Fourier-transform infrared (FTIR) spectroscopy, the degree of conversion of liquid resin and post-processed materials was analyzed. This investigation focused on the effects of various post-curing environments (nitrogen vs. air) and rinsing protocols (centrifuge, ethanol, isopropanol, and isopropanol + water). The assessed mechanical properties were flexural modulus and hardness. Results: The degree of conversion showed no significant variance across different groups, though the polymerization environment influenced the results, accounting for 24.0% of the variance. The flexural modulus varied considerably, depending on both the rinsing protocol and the polymerization environment. The standard protocol (centrifugation followed by nitrogen polymerization) exhibited the highest flexural modulus of 1881.22 MPa. Hardness testing revealed significant differences, with isopropanol treatments showing increased resistance to wear in comparison to the centrifuge and ethanol rinse treatments. Conclusions: This study conclusively demonstrates the adverse effects of oxygen on the polymerization process, underscoring the critical need for an oxygen-free environment to optimize material properties. Notably, the ethanol rinse followed by nitrogen polymerization protocol emerged as a viable alternative to the conventional centrifuge plus nitrogen method.

• Keywords (english): polymerization; mechanical properties; polyurethane
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Polymers
• Numbering: vol. 16, no. 1, 17
• e-ISSN: 2073-4360
• DOI: https://doi.org/10.3390/polym16010017
• URN:NBN: urn:nbn:hr:127:966292
• Publication: 2023-12-20
• Document URL: https://www.mdpi.com/2073-4360/16/1/17
• Type of resource: Text
• Access conditions: Open access
• Created on: 2024-07-02 08:45:30