Can I Reuse an Old Digital Scan for a New Night Guard?

An old digital dental scan does not automatically become unusable simply because time has passed.

The more important question is whether the scan still represents your teeth as they are today.

If your dental anatomy has remained largely unchanged since the scan was taken, an existing STL or PLY file may still be suitable for a new custom night guard. If your teeth or dental restorations have changed, an updated scan or impression may be needed.

Does a Digital Dental Scan Expire?

Not in the way a physical material ages or deteriorates.

A digital scan is a stored three-dimensional record of your teeth at a particular point in time. The file can remain unchanged for years. What may change is the mouth the file represents.

That is why there is no single age at which every digital dental scan suddenly becomes unsuitable for a night guard.

A relatively old scan may still closely reflect someone’s current teeth, while a much newer scan could become outdated after orthodontic treatment, a new restoration, an extraction or significant tooth movement.

When Might an Existing Scan Still Be Usable?

An older scan may be worth reviewing when your teeth have remained stable since it was taken.

That generally means there have been no meaningful changes such as:

• orthodontic movement from braces or clear aligners,
• new crowns, veneers, implants or other restorations that alter tooth shape,
• tooth extractions,
• chipped, fractured or noticeably worn teeth,
• noticeable tooth movement or changes in how your teeth come together.

The scan itself also needs to contain adequate dental information for fabrication. A file can be current in age and still require another export if portions of the arch are incomplete or the file was not provided in a usable format.

If your question is about file type or scanner compatibility rather than scan age, see our dental scanner and STL/PLY compatibility guide .

When Is a New Scan or Impression the Better Choice?

An updated dental record is generally the more appropriate starting point when the older scan no longer reflects the shape or position of the teeth involved in the appliance.

This can happen after dental treatment or naturally occurring changes in the mouth.

For example, a crown placed after the original scan may change the contours of a tooth. Orthodontic treatment can change tooth position. An extraction changes the dental arch entirely in that area.

In those situations, fabricating from the older record could mean building the appliance around anatomy that is no longer current.

Can Sentinel Tell Whether My Teeth Have Changed?

We can review a submitted file for things such as scan coverage, visible completeness and whether the digital data can be used within our laboratory workflow.

What an older scan cannot tell us on its own is what happened after the scan was created.

If you have had dental work, orthodontic treatment, tooth movement or another change since the scan was taken, let us know. If you are unsure whether your teeth have changed significantly, your dentist or orthodontist is the best person to evaluate your current dental condition.

What If the Scan Looks Fine but the File Will Not Work?

Scan age and file usability are two separate issues.

Sometimes the underlying scan is still useful, but the dental office has exported it in a way our laboratory cannot use. In that situation, we may ask for a different export of the existing scan rather than asking you to have your teeth scanned again.

Sentinel currently accepts qualifying STL and PLY files.

For the current upload process, see How to Send an STL or PLY Digital Dental Scan for a Custom Night Guard .

What If I Am Not Sure Whether to Reuse the Scan?

Start with what you know about your dental history since the scan was taken.

If nothing meaningful has changed, the existing file may be worth submitting for review. If you know your teeth have changed, or you are uncertain after significant dental or orthodontic treatment, an updated scan or impression may provide a more current record.

If you are deciding between having a professional digital scan made and taking an at-home impression, our dental impression vs. digital scan guide explains the differences between the two workflows.

What About Future Reorders?

One advantage of a digital workflow is that the model can be retained for future use.

Sentinel can store submitted digital dental scans, which can make a future reorder simpler when the teeth have not changed.

That is a slightly different question from whether an outside scan is still current, so we cover it separately in our guide to reordering from a saved 3D dental model .