Instead of thermoforming splints from a sheet, they can now be directly 3D-printed. This overview article describes a shape-memory material and what it means for treatment.
Directly printed shape-memory aligners (TC-85): Overview of material and application.
Shape memory aligners – A new dimension in aligner orthodontics
Prepared for patients by Dr. Julia Steinmaier.
Aligner treatment has become firmly established in orthodontics over the past two decades.1 One particularly exciting development is so-called shape-memory aligners: clear trays fabricated by 3D printing that possess a “shape memory.” We explain here in understandable terms what lies behind this technology and what advantages it offers for patients.
What are shape memory aligners?
Conventional clear aligners are usually thermoformed from a plastic sheet.2 Shape-memory aligners, in contrast, are fabricated directly by 3D printing from a special material. The term “shape memory” describes a particular property of this material: even if the aligner is deformed, it returns to its originally planned shape at body temperature.
Gentle, consistent force
Thanks to this property, the aligner exerts a constant, gentle force on the teeth without the effect diminishing with wear.3 This enables physiological, gentle tooth movement and can increase wearing comfort. Before insertion, the aligner can also be briefly placed in warm water, making it more flexible and more comfortable to wear.
Better fit and improved hygiene
Because the aligners are directly printed, their thickness is very uniform and the fit is especially precise. Another advantage concerns hygiene: the material is heat-resistant and can be cleaned at higher temperatures, which reduces bacterial load—something not possible with conventional plastic aligners, as they would deform in the process.
A treatment example
An adult patient desired a more harmonious smile. She had gaps in the front and posterior tooth areas as well as a missing tooth that had led to shifting. Using clear aligners from our own practice, the teeth were first moved into the planned position. Afterward, a dental colleague minimally invasively filled the remaining small gaps with tooth-colored composite material. The result was an even, harmonious smile—achieved with a gentle, nearly invisible treatment. Modern clear aligners are also used in our practice.
What this development means
Shape memory aligners demonstrate how aligner therapy continues to advance technologically: more precise fit, more consistent forces, better hygiene, and a more sustainable manufacturing process. As with any aligner treatment, the key to success here is careful planning and reliable wearing of the aligners.4
Sources
- Zheng, M., Liu, R., Ni, Z., & Yu, Z. (2017). Efficiency, effectiveness and treatment stability of clear aligners: A systematic review and meta-analysis. Orthodontics & Craniofacial Research, 20(3), 127–133. https://doi.org/10.1111/ocr.12177
- Elkholy, F., & Lapatki, B. G. (2018). Recommendation of a novel film-thickness sequence, 0.4, 0.5 and 0.75 mm, for aligner systems. Journal of Aligner Orthodontics, 2(4), 295–304.
- Bock, H., Bock, J., Karbach, F., et al. (2022). Material properties and first clinical applications of CA Pro, a novel aligner foil. Journal of Aligner Orthodontics, 6(3), 163–181.
- Krieger, E., Seiferth, J., Marinello, I., Jung, B., Wriedt, S., Jacobs, C., & Wehrbein, H. (2012). Invisalign® treatment in the anterior region: Were the predicted tooth movements achieved? Journal of Orofacial Orthopedics, 73(5), 365–376. https://doi.org/10.1007/s00056-012-0097-9
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