3D Printing in Aligners Staging Orthodontics: A Review

Abstract

Clear aligner therapy (CAT) has become a cornerstone of modern orthodontics, offering aesthetic, comfortable, and efficient alternatives to conventional braces. Accurate staging of tooth movements is essential for treatment success, yet traditional manual workflows are prone to errors, inconsistencies, and prolonged treatment duration. The advent of 3D printing, coupled with AI-assisted digital workflows, has transformed aligner fabrication by enabling both indirect model-based and direct aligner printing with biocompatible photopolymer resins. These technologies improve precision, reproducibility, and patient-specific customization while reducing production time and material waste. Treatment planning software with machine learning optimizes force application and predicts tooth movements, enhancing clinical outcomes. Factors such as printer type, resin properties, layer thickness, and algorithm sophistication critically influence staging accuracy. Overall, the integration of 3D printing, advanced materials, and digital planning establishes a new paradigm in orthodontics, enabling faster, more accurate, and patient-centered aligner therapy with potential for teleorthodontic monitoring and same-day production.

Introduction

Clear aligner therapy (CAT) has become a major advancement in orthodontics, driven by the need for accurate, controlled staging of tooth movements. Each aligner typically moves teeth 0.15–0.25 mm per stage, making precise digital modeling essential to ensure predictable biomechanics and treatment success. Traditional manual fabrication methods were slow, inconsistent, and unsuitable for complex cases. The introduction of 3D printing—especially SLA and DLP—has transformed aligner production by offering higher precision, improved reproducibility, faster workflows, and compatibility with AI-driven staging algorithms. Advances in materials, including durable and transparent light-cured resins, support the structural reliability and biocompatibility required for aligner therapy.

The literature shows that 3D-printed aligners achieve high dimensional accuracy, enhanced fit, and clinically acceptable tooth-movement precision, with reported accuracies of 64–72% for most tooth movements and near-perfect accuracy for transverse dimensions. New resin formulations with shape-memory properties also improve biomechanical control. However, challenges persist regarding long-term material behavior, surface quality, and the lack of standardized testing protocols, highlighting the need for more clinical trials.

Multiple 3D printing technologies serve orthodontic applications. SLA offers high precision and smooth surfaces; DLP provides rapid, accurate, high-volume production; FDM remains limited to non-clinical uses; and PolyJet printing enables multi-material, high-detail models at higher cost. Material selection is critical: biocompatible photopolymer resins are used for dental models, while thermoplastics such as PU, PETG, PC, and multilayer polymers are commonly used for traditional thermoformed aligners. Emerging directly printed aligners made from resins like Tera Harz TC-85 eliminate thermoforming distortion and support same-day fabrication.

The digital workflow integrates intraoral scanning, CBCT imaging, AI-assisted treatment planning, and 3D printing to improve diagnostic accuracy, streamline production, and enable remote monitoring. Staging accuracy depends on printer technology, resin properties, curing protocols, layer thickness, and planning software sophistication. Optimizing these factors enhances treatment efficiency, reduces refinements, and improves patient comfort and clinical outcomes.

Conclusion

3D printing has revolutionized aligner staging by enhancing precision, efficiency, and patient-specific customization. Direct printing of clear aligners eliminates the need for thermoforming, streamlining production and improving material consistency. ombined with biocompatible materials and teleorthodontic integration, these advancements support more effective, patient-centered orthodontic care.

References

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