Retainers
After braces or aligners finish moving your teeth, the bone and gum tissue around them need time to stabilize in the new positions. Teeth that aren't held in place can gradually drift back toward where they started, and that is what retainers are for.
Retainers come in removable and fixed, or bonded, forms. Removable retainers are typically worn full-time for a period after treatment, then scaled back to nights only, based on your orthodontist's instructions. A fixed retainer is a thin wire bonded behind the front teeth that stays in place continuously.
How long you will need to wear a retainer, and in what form, depends on your treatment and your orthodontist's assessment, but in general, some form of long-term retention is part of keeping your finished results stable over time.
Clinical detail
Post-treatment appliances, removable (e.g. Hawley, vacuum-formed) or fixed lingual bonded wire, intended to maintain tooth position during periodontal and osseous reorganization following active tooth movement. Retention protocol, including appliance type, wear schedule, and duration, is individualized; extended part-time wear is often recommended given the lifelong potential for physiologic dental drift.