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Cytotoxic effect of 3D-printed and thermoformed clear aligner materials on human oral fibroblasts: An in vitro study

Ružica Bandić, Ivna Vuković Kekez, Katarina Vodanović, Nensi Bralić, Vedrana Čikeš Čulić, Ivana Medvedec Mikić et al. · 2025 · 5 citationsRead the paper

Objective: To compare the cytotoxicity of three dimensional (3D)-printed resins and conventional materials used for orthodontic aligner production. Methods: 3D-printed materials such as 3Dresyn OD-Clear, Clear A, and Tera Harz TC-85 were compared with one thermoplastic material-Duran+. The samples were stored in artificial saliva at 37°C for 7 and 14 days to simulate the oral conditions during one phase of aligner therapy. The saliva was subsequently diluted with cell culture medium to concentrations of 10% (c1), 20% (c2), and 30% (c3). The cytotoxicity of the materials was assessed in human oral fibroblasts using the CCK-8 assay after incubation periods of 4 hours, 24 hours, 48 hours, and 72 hours. Results: > 0.05). Conclusions: Among the tested materials, 3Dresyn OD-Clear and Duran+ demonstrated consistently good biocompatibility, highlighting their potential for safe clinical use. Although the other materials were generally biocompatible, they exhibited cytotoxic effects under certain conditions, underscoring the need for thorough testing to ensure safe clinical use.

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3Dresyn OD-Clear (Material A) and Duran+ (Material D) demonstrated good biocompatibility with cell viability consistently above the 70% threshold. (Human oral fibroblasts, various concentrations (10-30%), and incubation times (4-72h))
Clear A (Material B) exhibited cytotoxicity at the highest concentration after 7 days in saliva. — 62.9% cell viability (30% concentration (c3), 72-hour incubation)
Tera Harz TC-85 (Material C) exhibited cytotoxicity at the highest concentration after 14 days in saliva. — 69.2% cell viability (30% concentration (c3), 72-hour incubation)
No statistically significant difference in cytotoxicity was found between 7 and 14 days of simulated oral exposure for any material. — P > 0.05 (All tested materials and concentrations)

Setup: Four materials (3Dresyn OD-Clear, Clear A, Tera Harz TC-85, and Duran+) tested on human oral fibroblasts (HOrF) seeded at 5,000 cells/well in 96-well plates.
How: The study used a CCK-8 assay to measure the metabolic activity of human oral fibroblasts exposed to extracts of 3D-printed and thermoformed materials. Materials were soaked in artificial saliva for 7 and 14 days, then diluted to 10%, 20%, and 30% concentrations and incubated with cells for 4 to 72 hours.
Limitations: In vitro study using cell lines may not fully replicate in vivo oral mucosal responses. · Potential nutrient deficiency in the highest concentration (c3) may have contributed to lower cell viability results.

Summarized by Gemma 4 from the open-access full text · 8 Oct 2026. Read it