Completed orthodontic treatment does not guarantee perfectly straight teeth for the rest of your life. Teeth have a memory and often try to move back to their original positions. Retainers are required to keep your teeth in their new positions. Regular retainer wear is necessary for lifetime as your body is continually undergoing growth and maturation. Minor irregularities, particularly in the lower front teeth may occur. In summary, you need your retainers to keep your teeth as straight as possible. But even with good retainer wear, your teeth may move slightly.
This retention phase of treatment needs to be individually tailored for each patient and usually consists of wearing fixed retention appliances in conjunction with removable retainers which are designed to hold the teeth in place once orthodontic treatment has been completed.