Are 3D-Printed Aligners Ready for Clinical Use?

🔬 Are 3D-Printed Aligners Ready for Clinical Use?

Despite the rise of direct 3D printing in orthodontics, recent studies (2020–2025) reveal serious concerns about the biocompatibility, mechanical reliability, and regulatory status of current resins used for clear aligners. Here's what the latest evidence shows:

🧫 Biocompatibility: Still a Major Issue• A 2025 systematic review (Dantagnan et al.) found that ALL direct-printed aligners tested released UDMA monomers, even after standard curing.• Cytotoxicity was consistently higher than in conventional PET-G aligners.• A 2024 pilot study (Iodice et al.) showed that over-curing (e.g. 50 min) reduced fibroblast viability, possibly due to resin degradation.• Cleaning protocols matter: thermal centrifugation removed toxic residues better than isopropyl alcohol (Kim et al., 2024).

📉 Conclusion: These aligners may be safe in theory, but lack proven long-term safety in real clinical settings.

⚙️ Mechanical Properties: Rigid, Brittle, and Inconsistent• Compared to thermoformed materials, 3D-printed aligners showed: – Lower tensile strength – Higher brittleness after water exposure – Poorer surface smoothness and translucency (Neoh et al., 2025)• Some resins (e.g. Graphy TC-85) show shape-memory effects, but they still don’t match the flexibility of traditional PU-based aligners.

📉 Conclusion: They work, but performance varies widely and current resins lack durability under daily oral conditions.

🚫 Still No Regulatory Approval (as of 2024)A 2024 narrative review (Li et al.) reported that no commercially available 3D-printed aligner resin had received full clinical clearance.👉 Most research remains in vitro.👉 No high-quality clinical trials are yet available.

📌 Bottom LineDirect-printed aligners offer amazing potential in precision and customization……but they are not yet ready for routine clinical use.

✅ Until resins are proven safe, consistent, and approved, thermoformed aligners remain the evidence-based gold standard.

📚 References

1. Dantagnan et al., 2025 – https://doi.org/10.1016/j.ajodo.2025.101028

2. Willi et al., 2023 – https://doi.org/10.1093/ejo/cjac056

3. Iodice et al., 2024 – https://doi.org/10.1111/ocr.12819

4. Kim et al., 2024 – https://doi.org/10.1038/s41598-024-66150-6

5. Neoh et al., 2025 – https://doi.org/10.1016/j.ajodo.2024.06.010

6. Li et al., 2024 – https://doi.org/10.3389/fmats.2024.1438660