Preparing STL scans and impressions for an aligner lab

Every clear aligner starts with records. If the scan or impression is inaccurate, the setup is built on the wrong model, and the aligners will not fit as planned. A good clear aligner case submission saves time for everyone: fewer rejected files, fewer revisions and fewer fit problems at the first appointment. This guide covers how to prepare STL scans, physical impressions, photos and treatment goals for an aligner lab.

Intraoral scans: getting a clean STL

Most labs, including Alignova, accept STL files exported from common intraoral scanners. The scanner brand matters less than the quality of the scan itself.

Before you scan

Clean and dry the teeth. Saliva and debris create noise and distortion.
Remove anything removable: old retainers, partial dentures, temporary appliances.
Use retraction to keep cheeks and tongue out of the field.
Check for loose restorations or brackets that should be dealt with first.

While scanning

Capture full arches, including the distal surfaces of the last molars.
Include enough gingiva, especially in the areas where the aligner will be trimmed along the gum line.
Record interproximal areas carefully, as these matter for IPR planning and contacts.
Take a bite registration in maximum intercuspation, on both sides.

Before you export

Inspect for holes, voids, double surfaces and stitching errors. Rescan problem areas.
Confirm the bite is aligned correctly in the software.
Export upper and lower arches as separate STL files with clear names.

Physical impressions: what a lab needs

If you do not have a scanner, physical impressions can still produce good results when taken carefully.

Use an accurate, dimensionally stable impression material suited to orthodontic models.
Choose a tray that covers the full arch, including the last molars, without distorting soft tissue.
Check for tears, bubbles, drags and pulls, especially on occlusal surfaces and interproximal areas. Retake anything doubtful.
Include a bite registration.
Disinfect, label and pack impressions so they travel without distortion.

An impression that looks acceptable at chairside may show small defects in the lab. It is always quicker to retake now than to plan from a flawed model.

Clinical photos

Photos help the lab and reviewing orthodontist understand the case beyond the model. A standard set usually includes extraoral frontal and profile views, a smile view, and intraoral frontal, left and right buccal and occlusal views. Use cheek retractors, mirrors for occlusal shots and consistent lighting.

Writing treatment goals for your case submission

A clear set of goals is as important as the records. The lab cannot read your mind, and vague instructions lead to extra revisions. Be specific:

Chief concern: what the patient wants changed.
Arches: upper, lower or both.
Movements to achieve: for example, align anterior crowding, close spaces, improve overjet.
Movements to avoid: teeth not to move, such as implants, bridges or ankylosed teeth.
Restrictions: teeth where attachments should not be placed, or where IPR is not acceptable.
Planned restorative work: crowns, veneers or implants planned after treatment, and any spaces to hold for them, perhaps with pontics.
Auxiliaries: whether you are happy to use elastics, bite ramps or precision hooks.

Records for special situations

Refinement cases

For refinements, take fresh scans or impressions with attachments in place, unless the lab advises otherwise. Note which aligner stage the patient is on and describe what has not tracked.

Restorations and implants

Crowns, bridges and implants scan differently from enamel and will not move like natural teeth. Name them in your goals so the setup treats them correctly and attachments are placed sensibly.

Missing teeth and planned spaces

If a space is to be held or opened for a future implant or bridge, say so, and state whether you want a pontic in the aligner during treatment.

Relapse after previous orthodontics

Mention any fixed retainer still in place, and whether you plan to remove it before treatment. A bonded wire left in place will stop the teeth it covers from moving.

Submitting through the Alignova doctor portal

At Alignova, cases are submitted through the doctor portal at alignova.cloud. You upload the STL files or arrange physical impressions, add photos and treatment goals and submit. You can then track the case on your dashboard, message the lab on that case, review the orthodontist-reviewed 3D setup, request revisions and approve online. Nothing is manufactured until you approve. For a broader view of the process, see how it works and the overview for dentists.

If anything in the records is uncertain, say so in your notes rather than leaving the lab to guess. A short message explaining a difficult area of the scan or an unusual restoration often saves a full round of revisions later.

Common reasons cases are delayed

Missing distal molars or incomplete arches.
Bite registration missing or misaligned.
Voids or distortion in the interproximal areas.
Treatment goals left blank or too general.
Planned restorations not mentioned until after the plan is made.

Frequently asked questions

Which intraoral scanners does Alignova accept?

Alignova accepts STL files from common intraoral scanners. If you are unsure about your scanner's export, message the lab before you submit.

Can I submit physical impressions instead of scans?

Yes. Physical impressions are accepted. Take extra care with accuracy and packing so the impression arrives undistorted.

Do I need to send X-rays?

Diagnosis is your responsibility, and radiographs are part of a proper examination. Share any information that affects tooth movement, such as root issues or restorations, in your treatment goals.

What if the lab finds a problem with my scan?

The lab will contact you, usually through case messaging, and ask for a rescan or new impression of the affected area.

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