After a course of active orthodontic treatment, patients will typically wear retainers, which maintain the teeth in their improved positions while surrounding bone reforms around them. The retainers are generally worn full-time for a period, anywhere from just a few days to a year, then part-time (typically, nightly during sleep) for as long as the orthodontist recommends.

It is possible for the teeth to stay aligned without regular retainer wear. However, there are many reasons teeth will crowd as a person ages, whether or not the individual ever experienced orthodontic treatment; thus there is no guarantee that teeth will stay aligned without retention.

For this reason, many orthodontists prescribe night-time or part-time retainer wear for many years after orthodontic treatment (potentially for life). Adult orthodontic patients are more likely to need lifetime retention.