Assessment of different direct printed aligner resins for leaching of urethane dimethacrylate: an in vivo study

To evaluate the release of urethane dimethacrylate (UDMA) from the direct printed aligners using Tera Harz TC-85 resin (Graphy, Seoul, Korea) and Clear A resin (Senertek, Türkiye) in saliva samples at different time intervals.

This prospective quasiexperimental study included 2 groups: Group A Tera Harz TC-85 (Graphy, Seoul, Korea) and Group B Clear A resin (Senertek, Izmir, Türkiye), each with 13 participants. Patients wore aligners for more than 20 hours a day for 14 days. Whole saliva samples were obtained at several time intervals: T0 before aligners were inserted and T1, T2, and T3 after 24 hours, 7 days, and 14 days of usage, respectively. High-performance liquid chromatography was used to analyze the samples, and the average results were computed.

Results showed significant variations in UDMA leaching between groups A and B at all postintervention periods. Group B had a significantly greater mean UDMA release than Group A at T1, T2, and T3. Intragroup analysis revealed time-dependent increases in UDMA release in both groups.

The findings revealed significant differences in UDMA release rates between the two materials, with Tera Harz TC-85 consistently showing lower levels of leaching than Clear A resin over the 14-day study period. Tera Harz TC-85 has superior performance in minimizing UDMA leaching, while both materials maintained acceptable profiles under the study conditions.