Retainers/night guards: Braces create a beautiful smile, but the retainer maintains it while encouraging better oral hygiene long after its use goes away. Although retainers for teeth are most commonly used to hold straight teeth in place after braces, the advantages for your kids in wearing their retainers correctly go beyond that. Retainers for teeth are mostly used as the last phase of orthodontics treatment. After the braces have been removed, teeth can shift back to their original position. So, retainers are worn overnight (if not longer) can help maintain the position of straightened teeth.