If an aligner has gone missing or cracked, put a tray back in today, either the one you wore before it or the next one in the series, and then call the practice treating you. Those two steps protect most of the progress you have made. What causes real setbacks is leaving the teeth bare for a week or more, or jumping several trays ahead to make up time.
Choosing between the previous tray and the next one
The deciding factor is how far through the lost tray you were.
- Work out where you were in the current stage. If you had worn the lost tray for most of its scheduled time and were due to change within a day or two, the next tray is often the better choice because the teeth have probably reached most of the planned position.
- If you were early in the stage, go back one. The previous tray will fit the teeth well and holds the movement already achieved. It will feel a little loose, which is expected.
- Check the fit. Whichever tray you choose should press fully over the teeth and attachments. If the next tray will not seat, or causes sharp pain, take it out and use the previous one instead.
- Contact your dentist or orthodontist the same or next day. Tell them the tray number, upper or lower, and roughly how many days you had worn it. Do not wait for your next scheduled review.
If your provider has given you different instructions for this situation, follow theirs, because they know how your plan is staged.
Skipping ahead rarely saves time
Each tray is designed to move teeth a small, set amount from the position the previous tray left them in. Jumping two or three stages asks the teeth to make several steps at once. The tray may not seat properly, which means it is not applying the planned forces, and the teeth can end up off track. That usually costs more time than it saves, sometimes with a rescan and new trays.
A few days bare is very different from a few weeks
Teeth in the middle of aligner treatment sit in a temporary position held by the tray. Without it, they can start to drift within days, particularly the teeth that were moving most. A day or so while you sort out a replacement is generally manageable. A longer gap makes it more likely that later trays will not fit and the plan will need adjusting.
This is the main way losing an aligner differs from losing a retainer after treatment. A retainer holds a finished, settled result; an active aligner is part of a sequence still in motion. If your treatment has already finished and it is the retainer that has gone missing, our guide on a lost or swallowed retainer applies instead.
Cracked trays and chewed trays
A small chip or hairline crack in a tray that still sits fully on the teeth and does not scratch the tongue or cheek can often be worn until a replacement arrives. Ask your provider first. A tray that is split through, warped by heat, has a sharp broken edge, or has been chewed by a pet should not go back in the mouth. Switch to the previous or next tray as described above.
How a replacement is made
Aligners are produced from a digital treatment plan, so a single lost tray can usually be made again from the existing file without restarting. If you are well into a long plan, or your teeth have moved differently from what was predicted, your dentist may take a fresh scan first to make sure the remaining trays still match your teeth. When several trays fit poorly, a revised plan with new trays is sometimes needed.
Replacement times vary with the aligner system and the lab involved, so ask your provider what to expect. It is also worth asking at the start of treatment whether replacement trays are included or charged separately; our article on what affects aligner costs lists this as one of the details to check.
The small tooth coloured bumps called attachments affect this too, since a new tray must clip over them firmly. If one has fallen off, mention it when you call. Our explainer on attachments and IPR covers what they do.
Habits that stop it happening again
Aligners are often lost in the few minutes between taking them out and putting them back in. A tray on the edge of a plate, on a restaurant table or in a pocket without a case is easy to throw away or sit on. The fix is to make the case the only place the tray ever goes when it is out of your mouth.
Keep a second case in your bag, desk or car so there is never an excuse to wrap a tray in a tissue. Travel, gym sessions and flights break routines, so take extra care then. Pet dogs often chew trays left within reach, such as on a bedside table. Keep your most recent previous tray rather than throwing it out, so you always have a fallback.
Common questions
Do I have to restart treatment?
Usually not. A single tray can normally be replaced from the existing plan. A long gap, or teeth that have moved differently from the plan, may mean a rescan and some new trays.
Is it unusual to lose a tray?
No, it is a common mishap, and dental teams arrange replacements regularly. Putting a fallback tray in and calling promptly is what matters.
What if I threw out my previous trays?
Call your provider straight away. They may advise wearing the next tray if it fits, or arrange a replacement as a priority.
If you are a Lumi Dental aligner patient and a tray has been lost or damaged, contact us and we will help you work out which tray to wear and arrange the next step. You can also see our current offers or read about our general dental team.
