Bruxism is the clinical term for grinding the teeth or clenching the jaw. Bruxism is a common habit with a wide range of potential symptoms and side effects. In some cases, symptoms are so minimal that the patient isn’t aware that bruxism is a problem; at other times, symptoms may include painful or extremely sensitive teeth, aches in the muscles of the jaw, headaches, and damage and wear to the teeth and any dental restorations.


The two main types of bruxism are nocturnal bruxism, which occurs while the person is sleeping, and awake bruxism. The damage that can arise from both types of bruxism may be similar, though the symptoms of nocturnal bruxism tend to lessen during wakeful hours and the symptoms of awake bruxism tend to worsen during wakeful hours. The causes of bruxism are largely unknown, though it is believed that nocturnal and awake bruxism have different causes. In some cases, bruxism may be associated with certain neurological or psychiatric conditions, including autism, cerebral palsy, sleep apnea, epilepsy, Down syndrome, Parkinson’s disease, and some types of trauma.


Regardless of the nature of the bruxism, symptoms include excessive wear on the teeth; failure of restorations; fracture and breakage of the teeth; hypersensitive teeth; inflammation of the gums and other oral tissues; audible grinding noises; and irritation of the cheeks, lips, and tongue. Bruxism may also cause the muscles of the jaw to increase in size and become tender or fatigued, and it may lead to pain in the joints of the jaw and surrounding areas, including headaches.


Bruxism is most often detected during a dental examination, which reveals wear on the biting surfaces of the teeth and at which patients may report tooth pain. Bruxism is believed to be largely involuntary or semi-voluntary. Awake bruxism is believed to largely correlate with stress. In children, bruxism may arise as a response to the pain association with teething or earache. Awake bruxism also usually involves clenching, as opposed to grinding, and may be associated with other oral habits like nail biting, tongue thrusting, or cheek biting. Sleep bruxism is believed to be related to the central nervous system and may involve abnormalities in the neurotransmitters. It is also believed to be connected to stress and other sleep disrupters. While there is growing evidence that both types of bruxism are related to stress, this evidence is inconclusive. It is also believed that bruxism may be genetically indicated, and evidence shows that certain stimulant drugs, including alcohol and caffeine, may encourage bruxism.


Bruxism may also arise because of the positioning of the rows of teeth in relation to one another. The medical term for the imperfect or unsatisfactory positioning of the upper and lower teeth in relation to each other is malocclusion. Malocclusion may occur when the upper and lower jaws are disproportionate in size, or it may occur between just a few teeth that are abnormal in position, size, or shape. Historically, malocclusion was believed to contribute to bruxism, though this is not supported by sufficient evidence; however, some researchers claim that corrections to bite mechanics, including malocclusion, may cure bruxism.


In many cases, bruxism cannot be prevented and must instead be treated by repairing damage to the teeth and striving to prevent further damage. Many dentists prefer to perform more minimal or less expensive restorations on people with bruxism habits, as bruxism can prematurely erode or damage restorations. Dentists may prescribe dental guards, also known as occlusal splints, to help patients manage bruxism, though these tend to be used more for nocturnal bruxism, as they are worn only during sleep. These are usually made of acrylic and fit over the teeth, protecting them from wear due to excessive contact. Dentists may also recommend that people who experience tooth hypersensitivity due to bruxism use a desensitizing toothpaste. Because of the strong correlation between bruxism and stress, stress reduction techniques and sleep hygiene education may also be proposed as possible treatment modalities.