Author:
Kim Ji-Eun,Mangal Utkarsh,Yu Jae-Hun,Kim Gi-Tae,Kim Hoon,Seo Ji-Young,Cha Jung-Yul,Lee Kee-Joon,Kwon Jae-Sung,Choi Sung-Hwan
Abstract
AbstractThe study investigated the effects of temperature and centrifugation time on the efficacy of removing uncured resin from 3D-printed clear aligners. Using a photo-polymerizable polyurethane resin (Tera Harz TC-85, Graphy Inc., Seoul, Korea), aligners were printed and subjected to cleaning processes using isopropyl alcohol (IPA) or centrifugation (g-force 27.95g) at room temperature (RT, 23 °C) and high temperature (HT, 55 °C) for 2, 4, and 6 min. The control group received no treatment (NT). Cleaning efficiency was assessed through rheological analysis, weight measurement, transparency evaluation, SEM imaging, 3D geometry evaluation, stress relaxation, and cell viability tests. Results showed increased temperature and longer centrifugation times significantly reduced aligner viscosity, weight (P < 0.05), and transmittance. IPA-cleaned aligners exhibited significantly lower transparency and rougher surfaces in SEM images. All groups met ISO biocompatibility standards in cytotoxicity tests. The NT group had higher root mean square (RMS) values, indicating greater deviation from the original design. Stress relaxation tests revealed over 95% recovery in all groups after 60 min. The findings suggest that a 2-min HT centrifugation process effectively removes uncured resin without significantly impacting the aligners’ physical and optical properties, making it a clinically viable option.
Funder
Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education
Korea Evaluation Institute of Industrial Technology (KEIT), funded by the Korean Government
Institute for Project-Y Seed Grant of 2023
Publisher
Springer Science and Business Media LLC