Orthodontic retainers are custom-made devices, made usually of wires or clear plastic, that hold teeth in position after surgery or any method of realigning teeth.
They are most often used after dental braces to keep teeth in alignment due to the lifelong risk of relapse associated with recoil of periodontal fibres or forces from the surrounding soft tissues such as the tongue, lips and cheeks. Most patients are required to wear their retainer(s) every night at first, with many also being directed to wear them during the day – at least initially. There are four types of retainers typically prescribed by orthodontists and dentists: Hawley, Essix, Zendura, and Bonded (Fixed) retainers.
Role in Gravity
The maxillary Hawley retainer is seen floating around the wreck of the Explorer Space Shuttle. It is unknown who exactly it belonged to but it is likely that it belonged to Evans, since her mouth was open.