It can be beneficial to use a guard, or covering, to protect your teeth from grinding while sleeping. Similar to how a mouthguard protects teeth during sports, this layer prevents damage to the teeth that can occur naturally.
There are a wide variety of different types of mouthguards, ranging from pre-formed pieces to ones that are custom fitted to your teeth and jaws. Some of these can even be formed at home through a boil-and-bite process.
Typically these mouthguards cover your upper teeth only, but in certain instances they are used for the lower teeth as well.
Grinding of teeth can be a serious problem that does major damage to your teeth, so wearing a nightguard is an effective way to prevent this damage.