A retainer does just what it sounds like it does. It “retains” the teeth in their current position, although some retainers are used to make small changes to the position of the teeth and jaw. Some retainers are removable, and some are fixed on the teeth (not removable.) Retainers may be recommended for a variety of reasons. Some retainers are used before braces are placed, but most are used after the braces are removed, or the teeth are straightened.
A palatal expander is usually used before braces are placed to expand the upper jaw and reduce crowding. The upper jaw consists of 2 bones fused together in the middle, and a palatal expander applies light pressure in order to separate these bones slowly. The bones will be re-fused in their new position, allowing more space for the adult teeth to erupt. Sometimes a narrow palate can be caused by using a soother for too long, or from thumb sucking. The suction of these habits causes the jaw to grow in a narrower arch, eventually affecting the position of the teeth. The palatal expander has a small notch in the middle that needs to be turned every so often, and when the palate is successfully expanded, the appliance will be removed.
After braces, it is essential to use a retainer to keep the position of the teeth. Often without a retainer, the teeth will slowly drift back to their initial position. The post braces retainers can be either fixed or removable, and both have their pros and cons. Fixed retainers are small wires that are cemented onto the backside of either 4 or 6 of the upper and lower front teeth to maintain their position. The benefit of a fixed retainer is that you don’t have to remember to take it out and put it back in, so compliance is not an issue. The disadvantage of a fixed retainer is the difficulty in cleaning. There are more nooks and crannies where plaque builds up, and flossing can be more challenging.
A removable post braces retainer is a thin tray that can be put in and taken out for both the upper and the lower teeth. After braces, the trays are recommended to wear all the time besides eating and cleaning your teeth, and then just recommended to wear at night. The advantage of removable retainers is that it’s much easier to clean your teeth, but they require compliance and must be worn to work.