Fixed retainers

An entirely different category of orthodontic retainers are fixed retainers. A fixed retainer typically consists of a passive wire bonded to the tongue-side of the (usually, depending on the patient's bite, only lower) incisors. Unlike the previously-mentioned removable retainer types, fixed retainers cannot be removed by the patient. Some doctors prescribe fixed retainers regularly after Invisalign®, especially where active treatment have effected great changes in the bite and there is a high risk for reversal of these changes. While the device is usually required for at least  a year, it is often kept in place for life. Fixed retainers may lead to tartar build-up or gingivitis due to the difficulty of flossing while wearing these retainers. Whenever possible, patients often must use floss threaders to pass dental floss through the small space between the retainer and the teeth.