Retainers are custom-made dental appliances designed to maintain the position of your teeth after orthodontic treatment, such as braces or clear aligners. Once your teeth have been straightened, they naturally tend to shift back to their original positions. Retainers prevent this by holding your teeth in their new alignment. There are two main types of retainers: removable and fixed. Removable retainers, often made of clear plastic or acrylic, are worn as directed, usually at night. Fixed retainers are thin wires bonded to the back of your teeth to provide permanent support. Both types are essential to keeping your smile straight and healthy after orthodontic treatment.