Not only crooked teeth keep moving your whole life long, so do straight ones -
this is what makes the retainer phase is so important!
The process is a very slow one, but eventually you might see that a tooth is moving out of position or notice problems with chewing. This is why we recommend that our patients wear a permanent retainer affixed to the back of the teeth for life (!) once their teeth have been corrected.
It is a good idea to wear a removable retainer or aligner as well.
This is the best way to guarantee that beautiful smile will last your whole life!