Teeth Grinding

Multiple articles have incorrectly cited teeth grinding as a reflex of chewing activity; teeth grinding is more accurately classified as a habit. Reflex activities happen reliably in response to a stimulus, without involvement of subconscious brain activity, and teeth grinding does not. All habitual activities are triggered by one kind of stimulus or another, and that does not make the habit a reflex. Chewing is a complex neuromuscular activity that is controlled by subconscious processes, with higher control by the brain. During sleep, the subconscious processes become active, while the higher control is inactive, resulting in teeth grinding. Some teeth grinding activity is rhythmic (like chewing), and some is sustained (clenching). Researchers classify teeth grinding as “a habitual behavior, and a sleep disorder.”

Most teeth grinders are not aware of their habit, and only 5% go on to develop symptoms, such as jaw pain and headaches, which will require treatment. In many cases, a sleeping partner or parent will notice the teeth grinding before the person experiencing the problem becomes aware of it.

Teeth grinding can result in abnormal wear patterns of the occlusal surfaces, abfractions, and fractures in the teeth. This type of damage is categorized as a sign of occlusal trauma.

Over time, dental damage will usually occur. Teeth grinding is the leading cause of occlusal trauma and a significant cause of tooth loss and gum recession.

In a typical case, the canines and incisors of the opposing arches are moved against each other laterally, i.e., with a side-to-side action, by the medial pterygoid muscles that lie medial to the temporomandibular joints bilaterally. This movement abrades tooth structure and can lead to the wearing down of the incisal edges of the teeth. People who grind their teeth may also grind their posterior teeth, which will wear down the cusps of the occlusal surface. Teeth grinding can be loud enough to wake a sleeping partner. Some individuals will clench the jaw without significant lateral movements. Teeth hollowed by previous decay (caries), or dental drilling, may collapse, as the cyclic pressure exerted by teeth grinding is extremely taxing on the tooth structure.

The etiology of problematic teeth grinding is unknown, though several conditions are known to be linked to teeth grinding. It is theorized that certain medical conditions can trigger teeth grinding, including digestive ailments and anxiety.