Teeth are set in bone (a living tissue) and not in stone. Retainers are an essential part of the overall treatment. After your braces come off, expect a period of full-time retainer wear followed by nighttime wear. Retainers maintain the teeth in their newly established positions and allow the muscles and tissues to adapt and hold the teeth in this new relationship. As during active treatment, cooperation is essential for maintaining the result. However, even with retainer wear, some changes may occur as the teeth adapt to be able to function in their best position. Often, retainers may need to be worn indefinitely, at least at night. Your orthodontist can advise you best as to how long you need to keep wearing your retainers.