Temporomandibular joint syndrome (TMJ) is a common disorder that affects millions of people worldwide. It is a condition that occurs when the temporomandibular joint, which connects the jawbone to the skull, becomes inflamed and causes pain, stiffness, and discomfort in the jaw. There are several causes of TMJ, including injury, stress, teeth grinding, and arthritis. Fortunately, TMJ can be treated, and one of the best ways to do so is by visiting a dentist.