Bruxism is better known as tooth grinding. This means you slide the chewing surface of your bottom teeth over the chewing surface of your top teeth. It is also often accompanied by clenching the teeth together.
Have you visited the dentist and been told you need a crown? You’ve discussed it with friends and they said they had the same treatment, didn’t have a crown and have had no further problem. Now you’re wondering why your dentist has recommended one.