A custom bite guard helps to minimize or arrest the damaging affects of clenching or grinding. Clenching or grinding can cause loss of enamel, TMJ (jaw joint) pain, loosening of teeth, enlarged jaw muscles, and accelerate gum disease. Some researchers also feel it can contribute to gum recession.
A custom bite guard can also perform a second function in acting as an orthodontic retainer, keeping the teeth from shifting.
Although usually worn at night, the custom bite guard can also be used to protect the teeth during the day. This is helpful during athletics, working out, or sub-conscious clenching during the day, as one might during work. Some people wear it during a stressful commute.
Custom bite guards are much more precise and less bulky than over-the-counter (OTC), "boil and bite" guards. Custom bite guards can help tense and painful TMJs since, they are indexed only on one side, and are flat and smooth on the opposite side. This way, the jaw can slide into its most comfortable "home" position during wear. This position is then dictated by the muscles attached to the jaw joint, as opposed to a jaw position dictated by the alignment of the teeth, which may not be the best position for the jaw.
However, inexpensive OTC bite guards can be more practical for growing youth, with their constantly growing jaws. They can also be used as athletic mouth guards (also known as sport guards).