Which type of retainer is designed to bond to the lingual surface?

The bonded retainer is designed to adhere to the lingual surfaces of the teeth, typically using a composite resin. This type of retainer is placed after orthodontic treatment to help maintain the teeth in their new positions and prevent relapse. By bonding to the back surfaces of the teeth, it remains less visible and does not interfere with speech or oral hygiene as much as removable options might.

Other types of retainers serve different purposes: the Hawley retainer is removable and has a wire framework that sits against the labial surface, while clear retainers are also removable and designed for aesthetic appeal, fitting over the teeth without any bonding. Positioners are used to help shape the teeth and gums but are not specifically designed to bond to the lingual surfaces, making them unsuitable for the role described in the question. Understanding these distinctions highlights why the bonded retainer is the appropriate choice for this scenario.