Retainers do one thing, and one thing only. They hold your teeth in their new positions to help achieve stability. They are worn 24/7 to start, then, depending on your compliance, I will be able to shorten the number of hours per day that are required. They come in a variety of shapes, sizes, and materials. The 3 most common types, however, are the plastic tray-type retainer (Essex), the wire and plastic retainer (Hawley), and a wire bonded to the insides of your teeth (Bonded 3-3).