When you use a custom night guard, the device will be made specifically for the shape of your mouth, providing the best fit and protection. They are designed to fit comfortably and securely in your mouth so that you don't wake up with an uncomfortable or loose-fitting guard. Since these guards are custom-made, they provide an added layer of protection against grinding that generic, or over-the-counter night guards (i.e. bite and boil) devices cannot offer.