Retainers, as the name implies, retain (or hold) the teeth in their corrected positions.
There are several types of retainers commonly divided into removable (clear plastic tray) or fixed (wire glued behind the front teeth). The orthodontist will decide which retainer type is most suitable for each patient.
It is very important that the patient wears their retainer as directed by the orthodontist or their teeth will move. However, even with faithful patient cooperation it is possible that one or two stubborn teeth may try to rotate or move slightly. Therefore it is also important to continue regular retainer check appointments to maintain the alignment of your teeth.