3D-printed aligners in 2026: where the technology stands - and what it means for your planning
- Jesper Hatt DDS
- 3 days ago
- 5 min read
At the seventh European Aligner Society congress, Dr. Rooz Khosravi - clinical associate professor at the University of Washington and US ambassador for the European Aligner Society - gave a presentation on 3D-printed versus thermoformed aligners. Dental Tribune International published an interview covering his key points on April 21, 2026.
His assessment is worth reading carefully. Not because it overturns what we know, but because it frames some of the open questions with more precision than most of the current debate manages.
The material difference is real - and clinically relevant
Dr. Khosravi's starting point is precise. Thermoformed and 3D-printed aligners are not two versions of the same product. Thermoformed materials are heated above their glass transition temperature and shaped as they cool. 3D-printed aligners are built layer by layer through photopolymerisation of resin. The physical properties that result are genuinely different.
For clinical purposes, the most consequential difference is force retention. 3D-printed aligners currently generate less sustained force than thermoformed systems. Dr. Khosravi calls this "an undisputable fact." We agree. In a post from May 2025, we argued that printable resin materials were not yet ready for routine clinical use - partly for this reason.
Six years of development in resins, printers and post-processing workflows have moved the field forward. But the core clinical question - how does force delivery hold up across a full wear cycle? - is still not answered by published data in a way that supports routine use for active tooth movement.
Attachment-free therapy: a hypothesis, not a protocol
One argument made by proponents of 3D-printed aligners is that their superior fit eliminates the need for attachments. The logic is clear: if the aligner seats more precisely against the tooth surface, engagement features become redundant.
Dr. Khosravi's position is measured. He describes this as "a hypothesis grounded in the theory of better fit" that has, to his knowledge, not yet been proved scientifically.
That distinction matters for how you approach a case. Decisions about attachment design should rest on clinical evidence and case-specific risk assessment — not on a manufacturing claim. When attachment-free therapy is treated as an established protocol before the supporting evidence is in place, the predictability risk moves to your patient.
This is exactly where the AlignerService Risk Management System™ earns its keep. Whatever the aligner material, a clear hierarchy of case complexity still applies. Starting from that hierarchy — risk-based case selection before any appliance decision — protects outcomes regardless of which manufacturing method you use.
In-office printing: the potential is real,
but the breakeven threshold is high
Dr. Khosravi describes in-office 3D printing as "a must-have in a modern orthodontic practice." He points to retainers, indirect bonding trays, flippers and models as the immediate value drivers — and that framing is accurate.
But there is a significant gap between printing models and retainers, and printing aligners for active orthodontic treatment. We covered this in detail in July 2025. The short version: producing aligners in-house for active treatment requires CE-certified production under MDR Class IIa, an ISO 13485 quality management system, a trained and dedicated technician, and enough case volume to amortize the fixed costs. Based on the practices we have worked with directly, that threshold sits at roughly 100–150 aligner cases per year.
Below that volume, the anticipated cost savings disappear quickly into refinements, retakes and labor overhead. Above it, in-office production can be a genuine asset — but only when the clinical planning behind it is sound.
A precisely manufactured appliance cannot compensate for a treatment plan that asks the teeth to do things they cannot reliably do. That point holds regardless of whether the aligner was thermoformed in an industrial lab or printed at chairside.
The more interesting question
The part of Dr. Khosravi's interview that deserves the most attention is where he stops comparing 3D-printed aligners to thermoformed ones and asks a different question.
The conventional aligner, he argues, was shaped by the constraints of thermoforming: a uniform sheet of plastic formed around a dental model. 3D printing removes almost all of those constraints. Thickness can vary locally across the appliance surface. Engagement features can be built directly into the aligner body. Rigid and flexible zones can coexist within a single device. The result — in his framing — could be an appliance that sits between an aligner and a fixed appliance, delivering differentiated, controlled forces without the visibility and hygiene problems of brackets and wires.
Whether that category eventually gets called a smart aligner, a hybrid appliance or something else is less important than recognising what it implies for treatment planning.
If the appliance can deliver targeted forces at specific tooth surfaces, the planning process has to keep pace. The clinician — or their planning partner — needs to specify not just tooth positions at each stage, but force vectors, local material properties, and the biomechanical rationale for each design decision. That is substantially more demanding than planning for a uniform thermoformed sheet.
Dr. Khosravi acknowledges directly that the software is not there yet. Current aligner platforms are built around the thermoforming model: they generate a sequence of 3D models for vacuum-forming, not design parameters for direct-print appliances with variable geometry and internal structure. When the software does catch up, the quality of clinical thinking behind the plan will matter more, not less.
That is the direction of travel. And it is a reason to build strong clinical planning habits now, not after the hardware matures.
What this means for how you work today
For most general practices working with clear aligners today, the practical implications of this discussion are narrower than the technology debate suggests.
Thermoformed aligners from established manufacturers remain the most predictable option for active tooth movement. In-office printing has immediate value for models, retainers and indirect bonding trays — the applications Dr. Khosravi highlights are real, and the return on investment there is more straightforward. Direct-print aligner production is moving forward, but the clinical and regulatory questions around force delivery, biocompatibility, dimensional accuracy and software design have not been resolved in a way that makes it routine for active treatment.
What does not change, regardless of manufacturing method, is the quality of the plan behind the appliance. That reasoning — built on risk-based case selection, realistic biomechanics, and clinical co-creation with dentists and orthodontists, never technicians — is where we work.
If you are evaluating how in-office printing fits into your workflow, or working through a case where attachment design or case complexity raises questions, start with the clinical risk picture first.
Start with a Free Aligner Risk Check.
No obligation. No subscription. Just clear clinical feedback on whether your case is ready to move forward — and what the risks look like before treatment begins.
[Book your Free Aligner Risk Check →](https://www.alignerservice.com)
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Kind regards
Jesper Hatt DDS
P: +41 78 268 00 78
Jesper Hatt DDS is co-founder of AlignerService and co-author of Mastering Aligner Orthodontics. AlignerService has supported 2,000+ dentists across 19 countries with risk-based treatment planning and clinical co-creation for clear aligner cases.*
*Source: Khosravi R, interviewed by Schüller N. "The convergence of materials science and digital workflows: Where are we with thermoformed versus 3D-printed aligners?" Dental Tribune International, April 21, 2026.*
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