Dental retainers are custom-made devices used to keep your teeth in their new position after orthodontic treatment like braces or aligners. Without a retainer, teeth naturally try to shift back to their original alignment, a process known as relapse, which is why dentists often recommend long-term or even lifetime use. There are two main types, removable and fixed retainers, with common options including clear plastic retainers (Essix), traditional wire retainers (Hawley), and bonded retainers.