Hey there 
This is not a situation that has happened to me yet.
But, I would like to know what would happen if I lost or broke one of my aligners?
Should I continue with the next aligner tray or should I inform my orthodontist?
I would like some advice on the subject. Thank you 
We were told to keep my daughter’s previous aligner. If she loses the one she is on, she can go back to her old one to help keep her teeth from going out of alignment until the next stage of her treatment.
In case your aligners get lost, contact your orthodontist and inform them immediately. They will let you know what steps you should take. Though commonly I know some of my friends who lost theirs and they wore their previous aligner set until they’ve contacted their orthodontist.
I advise you to always inform your orthodontist in case your aligners get lost. They are always happy to help with any problems you might encounter.
My best friend lost her aligner a couple of times and she always informs her orthodontist right away. I guess this is the best way because they know the best option in case that happens. They might advise you to use the next aligner already or go back to the previous aligner. It depends on how long you’ve been using the aligner that you lost.
My best advice is to make sure that you don’t lose it. 
You should have a container where you could put your aligners when you remove it so you don’t lose it easily. Most people lose their aligners because they just wrap it in tissue.
I lost my aligner before and I didn’t inform the provider immediately that I lost it because I was so busy that I forgot. I didn’t wear any aligner for 2 weeks and that was a big mistake. I had to have a replacement because I was too far away from my next aligner so I couldn’t switch to that. I had a new impression and had a replacement for it instead.
This is a link also that may answer your question. Though this is only for the ClearCorrect provider, I think it is basically the same for other providers. ----https://aligners.co/reviews/clearcorrect/#what-happens-if-i-lose-or-break-my-aligners
I hope my grandson wouldn’t lose his. It would cost more money if he loses it.
I saw somewhere on a thread discussion that usually the provider will suggest you to move to your next trays. Keep them in for at least 2 weeks and adjust your schedule for the next set of trays. While others suggest that you go back to your previous tray. I’m not sure which is the best choice so best to contact your provider.
On another note, don’t wrap your aligners in a napkin because most cases of aligners being lost is throwing the napkins and forgetting that you had your aligners there. Always bring a container where you can put your aligner when you remove them for eating or brushing.
If you are mostly done with that set and it’s nearly your schedule to change aligners, you can move to your next trays. But if you are only a few days on the aligners you lost, you have to go back to your previous aligners. That’s why it’s also important to not throw your aligners because you might use it again in case you lost your present aligner.
Your dentist could either suggest you go back to your previous trays or move on with your next set depending on how long you wore the lost aligner.
The best thing to do is to prevent them from getting lost or breaking.
I’m just wondering, aside from the options of going back to the previous aligner or moving to the next ones, can’t you get a new aligner from your provider to replace the lost aligner?
I think this can be an option if your provider decides that it’s better for you to have a new one. The only problem is you have to pay for it.
Waiting for a replacement can take long time. If you just started with the tray that you lost and you asked for a replacement, just wear the previous tray. Don’t move to the next tray because it won’t fit no matter how hard you try.