Is it possible for an orthodontic retainer stop working?

Yes and No: If the retainer is worn as recommended then no. If you avoid wearing it or dont wear it for a period of time its possible the teeth will shift back into the position they were before ortho.

Yes: An orthodontic retainer can stop working if it is not worn or has been damaged. That, too, would depend on why the retainer is being used. Teeth have fiber attachments that keep them in place. Orthodontic movements stretch these fibers which break and reattach when the tooth is stable and held in place by the retainer. Retention for life is now the standard, and new aligners placed periodically.

It depends: It should not stop working if it is being worn adequately and is intact (without cracking). A retainer becomes tighter over time if the teeth start to move because of inadequate wear. Some patients feel that something is wrong if it loosens, but this is normal with good wear and an intact retainer.

If not worn: Retainers are a fantastic appliance to mitigate aging changes in teeth. I call them anti- wrinkle cream for your teeth. Worn appropriately, they work very well. If wear is inconsistent, the fit will slide away and it become difficult to wear. If this happens, take advil, (ibuprofen) push them on as hard as you can and wear them for several weeks full time to regain your original result.

Yes: If you go long periods without wearing it it will no longer fit properly.

Sort of: If worn exactly as directed each day, for as long as theorthodontist seems prudent, should be ok. If not worn as directed, teeth can slip. If damaged, teeth can slip. This isn't a diy fix for you, go back to the orthodontic specialist who made the retainer and have it checked. If that's a geographic problem, ask your dentist to refer you to a new orthodontist.

If not worn: If worn correctly and not broken, then only minimal changes can occur

Yes: The wires may fatigue over time and require adjustment. However, the amount should be minimal -- unless it has been dropped,squeezed, crunched, sat upon, or otherwise distorted. See your Orthodontist for evaluation. Good Luck.