Retainer Retainers are usually fabricated by the orthodontist or general dentist who performed the orthodontic treatment. This is customarily done by taking a mold, or impression, of the newly straightened teeth and fabricating the retainer out of wire and/or acrylic material. There are two types of Retainer Fixed Retainers The fixed type of retainer is usually a thin wire worn across the back of the lower or upper front teeth, which is bonded in place with a cement similar to that applied on the brackets of braces. Despite the fact that this type of retainer takes a little more work to keep clean, it has the best outcome because the bonded wire will hold the newly straightened teeth. Removable Retainers The removable type of retainer is usually a combination of a wire going across the front of the lower or upper front teeth held in place with a combination of acrylic material and hooks (or clasps) that insert in and around the back teeth to hold the retainer in place. Disadvantage : The obvious disadvantage of a removable retainer after braces is the fact that it can be lost or damaged and can even melt or change shape if it is exposed to high heat. It is also very important not to leave the retainer lying around the house since pets love to chew them!