Causes of Temporomandibular Joint Disorder

Temporomandibular joint disorder (TMJ disorder) is a condition in which the joint connecting the lower jaw to the skull functions unstably or does not coordinate smoothly as it normally should. When this joint is affected, patients may experience jaw pain, difficulty opening the mouth, clicking sounds while chewing, or a feeling that the jaw is misaligned, fatigued, or even temporarily locked at certain times.

This is a fairly common condition, but it is often overlooked in the early stages because symptoms may appear subtly, intermittently, or be mistaken for toothache, jaw muscle fatigue, or normal chewing habits.

What is the temporomandibular joint?

The temporomandibular joint is the joint that allows us to perform activities such as:

• Opening the mouth
• Chewing
• Speaking
• Swallowing
• Moving the lower jaw side to side

When this system loses balance between the joint – muscles – teeth – bite, patients may develop a variety of uncomfortable symptoms that can significantly affect daily life.

Common signs of temporomandibular joint disorder

Before understanding the causes, many people often notice symptoms such as:

• Clicking or grating sounds when opening the mouth or chewing
• Jaw joint fatigue or pain
• A feeling that the jaw is misaligned or the bite no longer fits as before
• Difficulty opening the mouth wide
• Jaw stiffness or occasional “jaw locking” sensation
• Pain radiating to the ear, temple, cheek, or neck

If these signs persist or recur frequently, patients should be examined to identify the cause and determine the appropriate treatment approach.

Causes of temporomandibular joint disorder

Temporomandibular joint disorder often does not arise from a single cause, but may instead be associated with multiple contributing factors over a prolonged period of time.

1. Misaligned teeth and bite issues

One of the most common causes is an unstable bite or improperly aligned teeth, such as:

• Crooked teeth
• Gaps between teeth
• Crowded teeth
• Missing teeth or long-term tooth loss
• Misaligned bite, deep bite, crossbite, or open bite

When the teeth and bite are not in proper harmony, chewing forces may be distributed unevenly, creating abnormal pressure on the temporomandibular joint and chewing muscles.

2. Teeth grinding or clenching habits

Teeth grinding is a fairly common risk factor, but many people are unaware of it, especially when it occurs during sleep.

When teeth grinding persists over time, the teeth – muscles – joint system is subjected to repeated pressure for long periods, which may lead to:

• Wear of the chewing surfaces
• Jaw muscle pain
• Facial muscle tension
• Bite misalignment
• An increased risk of temporomandibular joint disorder

In addition to grinding, the habit of clenching the teeth during stress may also contribute to overloading the jaw joint.

3. History of jaw and facial trauma

People who have experienced accidents, impacts, or trauma to the jaw and face are also at higher risk of developing temporomandibular joint problems, especially if the trauma directly affects:

• The lower jawbone
• The condyle position
• The joints on both sides of the jaw
• The muscles and ligaments around the joint

In some cases, an old injury may not cause obvious symptoms immediately, but it can still leave long-term effects on joint function.

4. Imbalanced chewing habits

Some everyday habits that may seem harmless can also affect the temporomandibular joint if they continue over time, such as:

• Chewing on only one side for a long time
• Frequently eating foods that are too hard or too chewy
• Opening the mouth too wide when eating or yawning
• Biting hard objects with the teeth

When the jaw repeatedly functions unevenly on one side or is subjected to excessive force, the risk of overloading the joint and chewing muscles increases over time.

5. Prolonged stress and tension

Psychological factors may also be associated with temporomandibular joint disorder. People who frequently experience stress, anxiety, or prolonged pressure tend to be more likely to develop:

• Jaw muscle tightness
• Unconscious teeth clenching
• Teeth grinding during sleep
• A feeling of jaw fatigue or temple headaches

In many cases, stress is not the sole cause, but it can make symptoms more noticeable or prolonged.

6. Certain neuromuscular-related issues

In some individuals, temporomandibular joint disorder may be related to abnormal coordination of the neuromuscular system in the chewing area, which can alter muscle reflexes, jaw movement, or the ability to control biting force.

These factors may increase the risk of:

• Teeth grinding
• Prolonged muscle tension
• Jaw movement disorders
• Which may further contribute to unstable temporomandibular joint function

Should temporomandibular joint disorder be treated early?

If symptoms only appear briefly, many people tend to underestimate or ignore them. However, when the condition persists or recurs frequently, early examination is highly important.

Timely treatment may help:

• Identify the underlying cause
• Reduce pressure on the joint and chewing muscles
• Prevent the condition from progressing
• Support improvement in chewing, jaw movement, and overall quality of life

Each case may require a different management approach depending on the cause, ranging from habit adjustments and bite control to more in-depth intervention if necessary.

TMJ disorder examination at Phuong Thanh Dental Clinic

At Phuong Thanh Dental Clinic, patients suspected of having temporomandibular joint disorder will be carefully evaluated by the dentist based on clinical symptoms, bite condition, and jaw movement function. Accurately identifying the cause is an important step in developing an appropriate treatment plan and supporting more stable long-term improvement.