Bruxism is the clenching or grinding of teeth.
The condition commonly happens at night time and often can occur without symptoms until signs of wear are seen in the mouth by your dentist.
Bruxism can cause some symptoms including headaches (especially in the morning), sore jaw muscles, sensitivity of teeth and even toothaches
Tooth wear can also be associated with certain airway or breathing conditions like sleep apnea, so your dentist may discuss this with you as well.
A night guard or a bite splint is an occlusal appliance that is commonly used to help alleviate the complications associated with bruxism.
Have a look at this Spear Education video to see how a night guard can help you if you are clenching or grinding your teeth.