A dental retainer is a custom-made orthodontic appliance used to keep teeth in place after dental braces are removed. There are two types of retainers after braces: Fixed and removable. Selecting the type typically depends on the clinical needs and the patient preference. Teeth can shift in a very short period of time, sometimes within a week or two, making wearing a retainer even more important. Retainers keep your teeth from drifting and preserve that beautiful smile you have worked so hard to get.