Bruxism is the problem of too much tooth grinding or jaw clenching. It is not a normal use for teeth like eating or talking. Bruxism is a common problem that affects 8–31% of people. Bruxism can wear down teeth, make them too sensitive, and cause headaches and jaw pain. It can also harm dental work like crowns and fillings. Sometimes these problems are not noticed, so not everyone with bruxism knows they have it.