Bleilöb Maximilian, Welte-Jzyk Claudia, Knode Vanessa, Ludwig Björn, Erbe Christina
Department of Orthodontics and Dentofacial Orthopedics, University Medical Center of the Johannes Gutenberg-University Mainz, Augustusplatz 2, 55131, Mainz, Germany.
Department of Orthodontics, University of Homburg, Saar, Germany.
Sci Rep. 2025 Jan 25;15(1):3279. doi: 10.1038/s41598-025-85359-7.
Direct printed aligners (DPAs) offer benefits like the ability to vary layer thickness within a single DPA and to 3D print custom-made removable orthodontic appliances. The biocompatibility of appliances made from Tera Harz TA-28 (Graphy Inc., Seoul, South Korea) depends on strict adherence to a standardized production and post-production protocol, including UV curing. Our aim was to evaluate whether design modifications that increase layer thickness require a longer UV curing time to ensure biocompatibility. Specimens with varying layer thickness were printed to high accuracy using Tera Harz TA-28 and the Asiga MAX 3D printer (Asiga SPS ™ technology, Sydney, Australia). UV curing durations were set at 20, 30 and 60 min. Cytotoxicity was evaluated using the AlamarBlue assay on human gingival fibroblasts. Cell viability decreased with increasing specimen thickness (significant for 2 mm [p < 0.001], 4 mm [p < 0.0001], and 6 mm [p < 0.01]) under the manufacturer-recommended 20-min UV curing. Extending the curing time did not improve cell viability. However, cell viability never decreased by more than 30%, meeting EN ISO 10993-5 standards for non-cytotoxicity. The standard 20-minute UV curing protocol ensures the biocompatibility and patient safety of Tera Harz TA-28 for material thicknesses up to 6 mm.
直接打印矫治器（DPA）具有诸多优点，比如能够在单个DPA内改变层厚，以及能够3D打印定制的可摘正畸矫治器。由Tera Harz TA - 28（韩国首尔Graphy公司）制成的矫治器的生物相容性取决于严格遵守包括紫外线固化在内的标准化生产和后期生产协议。我们的目的是评估增加层厚的设计修改是否需要更长的紫外线固化时间以确保生物相容性。使用Tera Harz TA - 28和Asiga MAX 3D打印机（澳大利亚悉尼的Asiga SPS™技术）高精度打印出具有不同层厚的样本。紫外线固化时间设定为20、30和60分钟。使用AlamarBlue检测法对人牙龈成纤维细胞进行细胞毒性评估。在制造商推荐的20分钟紫外线固化条件下，随着样本厚度增加，细胞活力下降（2毫米时显著，p < 0.001；4毫米时显著，p < 0.0001；6毫米时显著，p < 0.01）。延长固化时间并未提高细胞活力。然而，细胞活力从未下降超过30%，符合EN ISO 10993 - 5的无细胞毒性标准。标准的20分钟紫外线固化方案可确保Tera Harz TA - 28对于厚度达6毫米的材料具有生物相容性和患者安全性。
