Now that your teeth are straight, how do you keep them straight? Simply use the retainer your orthodontist provided!
After your braces have been removed, retainers keep teeth from drifting and allow bone to rebuild. Retainers may be removable (worn when you go to bed), or fixed (bonded behind the teeth).
Teeth have memory. They want to go back to their original positions. It’s recommended that retainers be worn for as long as you’d like your teeth to remain straight. The most common retention protocol is 6 months full-time wear once your orthodontic treatment is completed, followed by nighttime wear for life.
–American Association of Orthodontists