When you've completed the moving part of your treatment, you're ready for the holding part! The next few months are the most critical part of your treatment! Your retainer is designed to hold your teeth in their corrected position until the bone surrounding the roots of the teeth "fill in" and make them "solid." If we do not retain (or hold) the teeth following orthodontic tooth movement, the teeth will move back towards their old positions and all that time wearing braces would be wasted.
If your retainer is going to do the job, here are the things you must do:
Congratulations on your new smile, use it frequently!