Table of Contents
Step-by-step guidance for thermoforming Zendura polyurethane sheet materials into clear aligners, retainers, and attachment templates — consolidated from the Instructions for Use published for each material. Complete IFC documents are available in Instructions for Use.
Before you form: sheet storage and handling#
Zendura materials are highly hygroscopic — they absorb moisture from ambient air, and absorbed moisture turns to steam during heating, causing bubbling, blistering, cloudiness, and weakened mechanical properties.
- Shipped pre-dried. Zendura sheets arrive fully pre-dried. Unlike PETG or acrylics, no pre-drying or oven-baking is required or recommended.
- Keep the foil pouch sealed. Sheets are packaged in high-barrier foil pouches with desiccant. Open the pouch only when you are ready to form.
- The 15-minute rule. Once the pouch is opened, thermoform the sheet within 15 minutes — less in high-humidity environments.
- Storage. Store unopened packages in a cool, dry place, away from direct sunlight and extreme temperatures.
- No protective film. Zendura sheets have no masking film to peel; both sides are identical — there is no “up” or “down” side.
Model preparation#
- Dry and fully cured. The 3D-printed or plaster model must be completely cured and dry — residual moisture or uncured resin can cause the sheet to bond permanently to the model or bubble during forming.
- Trim the base. Set the model low and flat, roughly 20–25 mm (¾"–1") tall. Taller models stretch the sheet too far and cause unacceptable thinning at the incisal edges.
- Block out undercuts. Fill deep voids, interproximal spaces, and undercuts with light-cure blockout resin or dental wax — otherwise the intimately-fitting material can lock onto the model and snap teeth during removal.
- Apply a separator. Coat the model with a thin, dry layer of model release agent, petroleum jelly, or a liquid foil separator (e.g., Al-Cote). For maximum optical clarity over 3D-printer build lines, use an ultra-thin separating film as a physical barrier between sheet and model.
Forming#
- Use positive pressure. Pressure thermoformers operating at 4 bar (60 psi) or above (5 bar preferred) give superior adaptation and detail reproduction over vacuum forming alone.
- Visual “sag” cue. On machines without programmed settings: swing the heating element over the sheet until the center of the sheet sags 12–20 mm (½"–¾") for Zendura A, FLX, VIVA, and AT — then form immediately. For Zendura TRAK, form as soon as the material starts to sag slightly.
- Fine-tuning. If the sheet does not adapt well, add 5 seconds of heating time. If it forms webs, folds, or bubbles, reduce heating time.
- Cool completely. Allow the formed sheet to cool under pressure on the model before releasing the chamber or handling the appliance. This relieves internal stress and prevents warping.
Machine settings#
Settings published in the materials’ Instructions for Use:
Zendura A (retainer material)#
| Thickness | MiniSTAR® | MiniSTAR® S | Biostar® | Drufomat Scan | Erkodent® |
|---|---|---|---|---|---|
| 0.625 mm | 220 °C · 35 s · code 132 | 220 °C · 30 s · code 122 | 220 °C · 45 s · code 152 | 205–210 °C · 1:15 | 205–210 °C · 1:25 |
| 0.76 mm | 220 °C · 40 s · code 142 | 220 °C · 35 s · code 132 | 220 °C · 50 s · code 162 | 205–210 °C · 1:20 | 205–210 °C · 1:30 |
| 1.0 mm | 220 °C · 45 s · code 152 | 220 °C · 40 s · code 142 | 220 °C · 55 s · code 172 | 205–210 °C · 1:30 | 205–210 °C · 1:40 |
Zendura FLX (aligner material)#
| Thickness | MiniSTAR® | MiniSTAR® S | Biostar® | Drufomat Scan | Erkodent® |
|---|---|---|---|---|---|
| 0.76 mm | 220 °C · 40 s · code 142 | 220 °C · 35 s · code 132 | 220 °C · 45–50 s · code 152/162 | 205–210 °C · 1:10 | 205–210 °C · 1:20 |
Zendura VIVA (aligner material)#
| Thickness | MiniSTAR® | MiniSTAR® S | Biostar® | Drufomat Scan | Erkodent® |
|---|---|---|---|---|---|
| 0.89 mm | 220 °C · 50 s · code 162 | 220 °C · 45 s · code 152 | 220 °C · 45–50 s · code 152 | 1:15 | 205–210 °C · 1:20 |
Zendura AT (attachment template material)#
| Thickness | MiniSTAR® | MiniSTAR® S | Biostar® | Drufomat Scan | Erkodent® |
|---|---|---|---|---|---|
| 0.38 mm | 220 °C · 25 s · code 112 | 220 °C · 20 s · code 102 | 220 °C · 30 s · code 123 | 205–210 °C · 0:55 | 205–210 °C · 1:00 |
Zendura TRAK (attachment template material)#
| Thickness | MiniSTAR® S | Biostar® | Drufomat Scan |
|---|---|---|---|
| 0.76 mm | 220 °C · 30 s · code 123 | 220 °C · 30 s · code 123 | 1:15 |
All settings assume at least 4 bar forming pressure unless noted. Always verify against the latest IFU for your material revision.
Cautions#
- ⚠️ Do not overheat. Excessive heating causes the sheet to sag too deeply — risking operator injury, machine damage, or extreme thinning of the appliance.
- ⚠️ Respect the 15-minute moisture window. Steam from absorbed moisture destroys clarity and mechanical strength.
- Zendura materials are contraindicated for patients with a known history of allergic reactions to plastics/polyurethane.
Next step: once formed and cooled, see Trimming Instructions for separating, trimming, and finishing the appliance.
