Clinical guide
3D Printed vs Thermoformed Aligners: A Clinical Guide
A side-by-side look at directly 3D-printed shape memory aligners and conventional thermoformed trays — written for orthodontists evaluating where each technology fits in modern clear aligner therapy.
Why the manufacturing route matters
Thermoformed aligners are produced by heating a polymer sheet (PETG, TPU, or a multi-layer composite) over a 3D-printed dental model. The sheet's thickness is uniform across the arch, and the geometry is constrained by what can be drawn over a model — including the cumulative errors from the model itself.
Directly printed aligners, by contrast, are built tooth-by-tooth from the CAD file. Each surface, margin, and wall thickness is defined on the screen and printed in a single workflow. There is no model and no draw step — so there is no thermoforming drift, and wall thickness can vary across the same aligner.
Shape memory effect (ta28)
Graphy ta28 is a photopolymer resin engineered around a thermally-triggered shape memory effect. A 30-second soak in lukewarm water softens the aligner, lets it seat fully into undercuts, and then it recovers its programmed shape at body temperature. The clinical consequence is a force curve that stays inside the biological optimum for the full 7-day stage, rather than spiking on day 1 and falling off by day 3 the way thermoformed PETG does.
Light, continuous force
Light continuous force is correlated with faster physiologic tooth movement and less patient-reported pain. Direct printing lets us tune wall thickness per tooth — thicker where active translation or torque is required, thinner where the aligner just needs to track. That local control is impossible with a uniform sheet. In our clinical workflow this is what allows a 7-day change protocol instead of the conventional 14 days, and is the main contributor to the up-to-50% treatment time reduction we see versus matched thermoformed cases.
Side-by-side comparison
| Attribute | Directly 3D-printed (DPA / Graphy) | Thermoformed (PETG / TPU) |
|---|---|---|
| Manufacturing | Direct 3D print, tooth-by-tooth | Thermoformed over a printed model |
| Material | Graphy ta28 shape memory resin | PETG / TPU sheet (uniform thickness) |
| Force profile | Light, continuous within biological limits | Heavy initial spike, drops within 48h |
| Thickness control | Variable per tooth | Uniform sheet — no local control |
| Shape recovery | Yes — recovers programmed form at body temp | No |
| Occlusal accuracy | Submillimeter, no model error | Cumulative model + thermoforming error |
| Attachments | Usually not required | Often required for complex moves |
| Disinfection | Heat-disinfectable at 100°C | Cannot tolerate boiling water |
| Aligner change cadence | Every 7 days | Every 14 days |
| Treatment time | Up to 50% shorter | Standard |
Hygiene and biocompatibility
ta28 cures in an oxygen-free environment, which removes the residual uncured oligomers that drive Type IV delayed hypersensitivity reactions seen with some thermoformed materials. The cured surface is non-porous and tolerates boiling water disinfection — a sterilization route PETG cannot survive. For patients with documented plastic sensitivities or those on immunosuppressants, this is a meaningful clinical lever.
Where thermoforming still fits
Thermoforming remains the cheapest path to a single retainer and is well understood by every lab. For one-tooth relapse, simple retention, or training cases, it is still appropriate. The case mix that benefits most from a switch to directly printed shape memory aligners is active treatment — anything where force profile, attachment count, and treatment time matter clinically.
Try DPA on your next active case
Submit a case through the DPA Portal and our clinical team will return a treatment plan tailored to a directly printed, 7-day-change workflow.
- 7-day stage change with continuous force.
- Variable wall thickness per tooth.
- Boil-disinfectable, optically clear.
- No mandatory attachments in most cases.