Temporomandibular joint (TMJ) disorder affects the jaw joints. People with TMJ disorder can easily develop sensitive teeth and other tooth and gum problems. The trigeminal nerve is a primary factor in TMJ tooth pain and sensitivity.
Tooth and gum problems are common in people with temporomandibular joint (TMJ) disorder. Health issues of the teeth and gums include:
- sensitive teeth
- tooth pain
- gingivitis or gum disease
- other bacterial infections
- tooth decay
- broken or misaligned teeth
- halitosis (bad breath)
Clenching/grinding the teeth, especially at night, is a cause as well as a symptom of TMJ disorder. Some people are unaware of grinding (bruxism) or clenching until a tooth shatters, or symptoms are extreme. See: Signs that You Clench or Grind Your Teeth at Night.
Grinding and clenching are subconscious, involuntary habits, and therefore difficult to stop. For tooth grinding (bruxism), a dental mouth guard or splint is sometimes effective. For tooth clenching, splints are rarely effective, and may cause the teeth to clench harder.
TMJ and Sensitive Teeth: The Trigeminal Nerve
Much of the pain of sensitive teeth comes from inflammation or irritation of the trigeminal nerve. The trigeminal nerve, also known as Trigeminal Nerve V, is the fifth of thirteen cranial nerves, extending from the brain stem into the face.
In people with TMJ disorder, dysfunction of the trigeminal nerve can cause a range of distressing symptoms including:
- sensitive teeth
- tooth and jaw pain
- facial pain and/or itching
- ear ache and/or itching
- muscle spasms
- numbness or tingling (facial paresthesia)
- eye pain or sensitivity
The trigeminal nerve emerges from the brain stem at the base of the skull. Like many nerves in the human body, the trigeminal nerve is paired. It branches into both sides of the face. As it enters the face, the trigeminal nerve splits into three subdivisions:
- V1 – ophthalmic (affecting the eye area)
- V2 – maxillary (upper jaw and teeth)
- V3 – mandibular (lower jaw and teeth)
(image: Gray’s Anatomy)
Smaller branches of the maxillary and mandibular nerves extend into each tooth to form part of the tooth pulp. The nerves also travel under and around the teeth.
Usually, the nerves in a tooth are well-protected. A hard coating of enamel covers the tooth. Beneath the enamel is a layer of dentine. Dentine is porous, filled with tiny tubules, which extend to the pulp beneath. The tooth pulp is a sensory bundle containing nerves, fibers and tissue.
People with TMJ disorder are especially vulnerable to worn enamel and tooth sensitivity or injury. Grinding and clenching the teeth can chip or erode the tooth enamel and expose the dentine. Tooth pain arises when a stimulus such as heat or cold travels down the minute tubules of the dentine and reaches the tooth pulp.
Exposure to hot or cold food and drinks, sugary sweets, or even a breath of cold air can inflame the exposed nerve endings. Nerve sensitivity causes stabbing pain or a dull, throbbing ache in the teeth.
Other Causes of Trigeminal Nerve Pain in the Teeth
Enamel erosion is only one reason the nerves might become inflamed and painful. The trigeminal nerve can become inflamed merely because of the constant pressure of clenching and grinding the teeth. As well, bacterial infections in the gums can cause nerve pain.
See: Symptoms of Gingivitis.
TMJ disorder affects the neck, and minor structural dysfunction of the vertebrae (for example a slipped disc) may compress or pinch the trigeminal nerve at the neck. Surrounding muscles, nerves, tendons or swollen tissue can also put pressure on the trigeminal nerve. Any of these conditions can irritate the nerves, causing pain and sensitivity in the teeth.