An over-the-counter (OTC) mouth guard will separate your top and bottom teeth while you sleep, preventing any grinding from damaging the teeth. However, an OTC mouth guard can’t be adjusted to balance your bite forces. Some people develop severe pain in their facial muscles from clenching on an unbalanced guard. In certain instances, irreversible damage may be done to the jaw joint and surgery may be required to correct the injury. We always recommend a custom, balanced guard for clenching and grinding – it’s simply safer and more predictable.