On May 21–22, 2025, the Shanghai Ninth People’s Hospital, affiliated with Shanghai Jiao Tong University School of Medicine, hosted a major academic seminar as part of its 105th anniversary celebration. Titled “New Technologies and Clinical Approaches in Orthodontics,” the event showcased advancements in digital diagnostics, biomechanics, and clinical techniques. A highlight of the event was the introduction of 3D printed aligners, a breakthrough in the field of orthodontics enabled by cutting-edge 3D printing technologies.
From Model-Based to Model-Free: A Smarter Workflow with 3D Print Aligners
Traditionally, clear aligners have been manufactured using an indirect process involving multiple steps. After capturing a digital scan of the patient’s teeth, doctors simulate tooth movement and 3D print dental models for each treatment stage. Thermoplastic sheets are then thermoformed over each model to create aligners. However, this method comes with limitations:
- Accuracy Loss:Force expression is often compromised, and torque precision may be limited to 50% of what is digitally designed.
- Uniform Material Properties:Thermoformed aligners have consistent thickness, which restricts biomechanical control.
- Design Constraints:Custom features like cut-outs, pressure zones, or reinforced structures are difficult to implement.
- Material and Time Waste:The need to print multiple physical models increases time, cost, and environmental burden.
Direct 3D Printing Aligners: The Next Evolution in Orthodontics
Prof. Fang Bing from the Department of Orthodontics at Shanghai Ninth Hospital presented their multicenter clinical research on direct 3D printed aligners, eliminating the need for physical dental models altogether. By using advanced dental design software and high-resolution resin-based 3D printers, orthodontists can now use 3D print aligners directly, delivering greater accuracy and customization.
Key Benefits of Direct 3D Printing Aligners:
- Enhanced Fit and Accuracy:Direct-to-print workflow ensures the aligners fit tightly and deliver the intended force accurately.
- Localized Mechanical Properties:3D print aligners can be engineered with varying thicknesses for different regions—stiff where needed, flexible elsewhere.
- Customization Freedom:Dentists can digitally add features such as force zones, voids for unerupted teeth, or integrated structural supports.
- Eco-Efficient and Scalable:Skipping the model-printing phase reduces waste and enables faster, scalable production.
With support from the National Center for Oral Medicine, a clinical study is now underway across nine hospitals, involving 300–400 patients, to evaluate the performance of 3D printed aligners in real-world scenarios.
Innovation Through Material Science and Advanced 3D Printing
The success of 3D printing aligners depends not just on the equipment but also on specialized materials. These aligners require biocompatible, flexible, and high-resolution dental resins capable of holding their shape and delivering precise forces. Unlike traditional thermoformed plastic, 3D printed aligners can be fabricated with exactly engineered contours and smooth mucosal interfaces.
Some unique clinical applications include:
- Guided Eruption Design:In mixed dentition, aligners can be 3D printed with strategic cutouts to allow space for erupting permanent teeth.
- Integrated Expansion Devices:Using 3D printing, aligners can incorporate one-piece palatal expanders for crossbite correction or arch widening.
- Space Management for Extractions:In complex cases like Class II malocclusions, local reinforcement within the aligner maintains anchorage and prevents tipping.
Research-Backed Performance and Clinical Validation
Prof. Xia Lungen elaborated on findings from the joint Orthodontic Biomechanics and AI Lab, co-founded with Leading MedTech. CT-based analyses confirm that 3D printed aligners demonstrate better fit, more uniform thickness, and superior force application compared to traditional thermoformed alternatives.
He noted that after years of rapid growth, the invisible aligner industry has reached a plateau. 3D print aligners open up a new pathway, offering orthodontists greater precision and control—especially valuable in treating difficult cases involving severe rotations, extraction spaces, or atypical crowding.
Conclusion
The rise of 3D printing aligners represents a new era in orthodontics—where digital workflows, customized resin materials, and direct manufacturing come together to deliver more effective, efficient, and eco-friendly treatments. As technology continues to evolve, 3D printed aligners may soon become the gold standard for modern orthodontic care.