Our bones are changing and reforming throughout our entire lives, which is why our bones can heal after we break them. Teeth are bone too, they continue to push forward as we mature regardless of whether or not you have had teeth extractions or braces. This is why, after your braces are removed, you need to wear a retainer. Retainers keep your teeth in place after orthodontic treatment to help prevent a possible relapse.
After you’ve had your braces removed, it will take some time for your teeth and gums to adjust to their new alignment. Retainers are used to keep your teeth in place during this transition until your teeth have stabilized. Typically, you would wear your retainers for the same length of time that you had braces. Some retainers are worn all the time during the first few months, and only at night after that; others are worn all the time for only a week, and then just at night. However every case is different, and your orthodontist will prescribe a retention plan based on your individual needs.