If you lost your retainer, the best next step is to start figuring out how it will be replaced rather than waiting to see whether your teeth move.
Editor’s Note
This article was updated on September 2, 2026 to reflect current replacement-retainer options, including the use of qualifying STL and PLY digital dental scans, and to remove overly specific tooth-shifting timelines
You may already have what you need. If your dentist or orthodontist has a current digital scan of your teeth, that record may be usable for a replacement clear retainer without taking another physical impression.
What Should You Do Right After Losing Your Retainer?
- Make sure it is actually gone. Check the case, bathroom, bedside table, luggage, car, restaurant bag or anywhere you may have removed it.
- Do not intentionally go without replacement simply because your teeth still look the same. Tooth movement after orthodontic treatment varies from person to person and may not be immediately obvious.
- Check whether a current digital scan already exists. Your dentist or orthodontist may have scanned your teeth during Invisalign, clear-aligner or other orthodontic treatment.
- If you do not have a usable scan, consider a new dental impression. Sentinel offers an at-home impression option for customers who do not already have an appropriate digital record.
- If your teeth already appear to have moved, contact your orthodontist before creating a new passive retainer. A replacement made from the current shifted position will generally preserve that position rather than automatically restore the earlier alignment.
How Quickly Can Teeth Move Without a Retainer?
There is no single timeline that applies to everyone.
The likelihood and amount of orthodontic relapse can depend on factors such as how recently active treatment ended, the original tooth movement, your individual biology and how consistently the retainer had been worn.
Some people may notice a change in fit relatively quickly, while others may not notice obvious movement for longer.
Because the timing cannot be predicted from a calendar alone, it makes more sense to begin arranging the replacement once you know the retainer is gone.
Do You Need to Go Back to Your Orthodontist?
Not necessarily for every replacement, but your orthodontist can be an important resource—especially if treatment ended recently or your teeth have visibly changed.
Your orthodontist or dentist may also have something particularly useful: a digital scan of your teeth.
If you had Invisalign, another clear-aligner system or digital orthodontic treatment, ask whether your dental office can provide your current scan as an STL or PLY file.
Have a Digital Scan? Check That First
Sentinel accepts qualifying STL and PLY digital dental scan files for clear retainer fabrication.
If the scan represents the tooth position you currently want to maintain and contains the anatomy our laboratory needs, it may be possible to use that record rather than creating a new physical impression.
During checkout, select the digital scan option. After your order is placed, you will receive an email with a secure link for uploading your scan files. Our laboratory reviews the submitted files before fabrication.
What If You Don't Have a Digital Scan?
You can still order a custom clear retainer.
If a usable digital record is not available, Sentinel's at-home impression process can be used to create the dental record for fabrication.
Retainer impressions need to capture the required dental anatomy clearly because the finished appliance follows those tooth contours closely. Our laboratory reviews impressions before fabrication, and another impression may be needed if important anatomy is shallow or incomplete.
For the full replacement process, see our Replacement Retainers: How to Replace a Lost, Broken or Worn Clear Retainer .
What If Your Teeth Have Already Shifted?
This is where a lost-retainer problem can become an orthodontic-position problem.
If you can see new crowding, rotation, reopened spacing or another meaningful change, do not assume that simply ordering another passive retainer will move the teeth back.
A retainer fabricated from a new scan or impression generally corresponds to the tooth position represented by that record. If the teeth have already shifted, the resulting appliance may maintain the shifted position.
If you want to restore your earlier orthodontic alignment, speak with an orthodontist before making a new passive retainer.
Learn more in Can Retainers Move Teeth Back? .
What If You Find Your Old Retainer Later?
If the retainer turns up after you have gone without it for a while, do not assume it should automatically be forced back onto your teeth.
If it still seats normally and appears undamaged, contact your orthodontist if you are uncertain about resuming wear.
If it fits only halfway, lifts on one side, requires biting pressure, causes significant pain or appears warped, do not force it.
See Retainer Doesn't Fit Anymore? What to Do Next for fit-specific guidance.
What If Your Dog Chewed the Retainer?
A chewed retainer is a damaged retainer, not simply a lost one that has been recovered.
Bite marks, cracks, distortion or missing material can change how the appliance seats. Do not try to heat, reshape or repair damaged thermoplastic at home.
If the damage is substantial, the appropriate path is generally replacement rather than attempting to restore the old appliance.
For damage-specific guidance, see What Should I Do If My Dental Retainer Breaks? .
Should You Order a Backup Retainer?
A backup can be useful if you travel frequently or simply want another appliance available if the primary retainer is lost or damaged.
The important consideration is that any backup should correspond to a tooth position that remains appropriate to maintain.
If significant time has passed or your teeth have changed, do not assume an older backup or old dental record still represents the position you want to preserve.
Can Sentinel Replace a Lost Clear Retainer?
Yes, when an appropriate current dental record is available for fabrication.
Sentinel clear retainers can be made from a qualifying professional STL or PLY digital scan or from an approved at-home dental impression.
View current options here: Sentinel Clear Dental Retainers .
The Bottom Line
Losing your retainer does not automatically mean starting orthodontic treatment over—but it is worth addressing the replacement rather than ignoring it.
First, find out whether a current professional digital scan already exists.
If your dentist or orthodontist can provide a qualifying STL or PLY file and your tooth position is still appropriate to maintain, that may be the simplest starting record for your replacement.
If no usable digital scan exists, an at-home impression remains an option.
And if your teeth have visibly shifted, address the orthodontic position before creating a new passive retainer intended to preserve it.