What Happens When Your Jaw Won’t Open?​​​​

​

1. When Your Jaw Won’t Open in the Morning

Jaw stiffness upon waking is commonly attributed to joint or muscle dysfunction occurring during sleep:

 

​Joint Issues: The TMJ’s shock-absorbing articular discs, comprised of cartilage, may have shifted out of alignment during sleep. By shifting out of alignment, they block the jaw from opening fully serving as a mechanical obstruction.

 

Muscle Tightness: Jaw muscles can tighten or spasm during sleep, particularly in individuals who exhibit sleep-related bruxism (teeth grinding), leading to difficulty opening the mouth fully. Sometimes this can be so severe that it might be hard to open up wide enough to fit a spoon in your mouth.​

​

2. When Your Jaw Won’t Open During the Day​​​

In some cases, the jaw may initially function without issue but become progressively restricted in movement throughout the day.

​

​Muscle Fatigue: Prolonged chewing, speaking, or stress-related clenching can overwork the jaw muscles.​

 

Postural Strain: Poor posture, such as hunching over a computer or phone, can strain the TMJ and surrounding muscles, restricting movement.

​

​Causes of Jaw Locking​

​

1. Disc Displacement

​​

The TMJ contains an articular disc that acts as shock absorber and allows smooth jaw movement. The disc sits in between the mandible (lower jaw) and temporal bone of the skull. The disc prevents bone to bone contact. When this disc shifts out of place, it can prevent and even block the joint from moving correctly.

​

• Articular Disc Displacement With Reduction: The displaced disc moves back into position during jaw movement. This is often accompanied by a clicking or popping sound. Temporary jaw locking may occur if the disc fails to realign smoothly. In medical terminology, "reduction" means that it moves back into place. 

​

• Articular Disc Displacement Without Reduction: The disc remains displaced and does not return to its normal position. This can lead to chronic pain, inflammation, and limited jaw mobility. In this case the disc does not "reduce" back onto place. Over time, this may also increase the risk of development of degenerative joint disease, also known as arthritis of the temporomandibular joint (TMJ).

​

Symptoms of Articular Disc Displacement Without Reduction:

• Severe limitation in mouth opening

• Jaw locking in a closed or partially open position

• Pain or tenderness in the TMJ area

• Pain or tenderness in the ear

• Swelling or inflammation around the joint

• Difficulty chewing or speaking comfortably

​

Imaging techniques such as MRI are helpful for diagnosing disc displacement. An MRI provides a detailed view of the cartilage articular disc in the TMJ. At times, other imaging techniques, such as a CBCT scan, are helpful to visualize the bony architecture of the joints as well.

​​

2. Muscle Spasms

​

Muscle spasms, particularly in the masticatory muscles, can restrict jaw movement and create significant discomfort. Spasms often result from trauma, or overuse of the jaw. Stress can also exacerbate muscle spasms.

​

Causes of Muscle Spasms:

• Daytime teeth clenching and grinding

• Nocturnal Bruxism: Occurring during sleep, nocturnal bruxism places strain on the jaw muscles

• Trauma or Injury: Direct impact to the jaw or head

• Posture: Poor posture can result in muscle strain and overuse

​

Muscle spasms are usually temporary but can greatly disrupt daily activities. They can cause a significant reduction in jaw opening making it hard to eat a sandwich or even open up wide enough to brush your teeth.

​​​​​​​​​​​​

What You Can Try When Your Jaw Won’t Open

​

1. Use Moist Heat to Relax Muscle Spasms

Moist heat can provide immediate relief for muscle tension. Follow these steps:

• Applying warm water to the jaw area, such as during a hot shower, can alleviate tension.

• Gentle massage of the jaw and temple areas during heat application can promote muscle relaxation.

• Try this for about 5 minutes to relax the muscles and improve jaw mobility.

​

2. Avoid Jaw Overuse Behaviors

Specific behaviors may aggravate jaw discomfort and locking symptoms:

• Nail-biting or chewing on objects like pens or pencils

• Teeth clenching or teeth grinding

• Poor posture, especially when using phones or computers. 

Identifying and reducing these habits can help minimize strain on the TMJ and muscles.

​

How Is Jaw Locking Treated?

​

Treatment for locked jaw is primarily dictated by its underlying cause. While disc displacement and muscle spasms are common culprits, it is often the combination of both factors that contributes to the limited opening. This is why a comprehensive diagnosis is essential to determine the most effective treatment plan. 

 

Disc Displacement Without Reduction

If the condition is related to disc displacement without reduction, therapeutic joint injections (also known as intra-articular injections) and mobilization techniques are often used to restore proper function to the temporomandibular joint (TMJ). In some cases, supplemental medications may be prescribed to alleviate pain and inflammation and promote healing. Additionally, a custom TMJ orthotic is commonly fabricated to ensure that the disc stays properly aligned, preventing future episodes of locking.

​

Muscle Spasms and Dysfunction

For jaw locking caused by muscle spasms, physical therapy focused on the jaw and surrounding muscles can be beneficial. In certain cases, muscle relaxants and an may be prescribed to reduce the tension. Additionally, behavioral modifications such as avoiding teeth grinding or jaw clenching are key to preventing further episodes.

​

For Jaws That Episodically Lock

For patients whose jaw locks intermittently, preventative measures can be helpful. Behavioral modification is important in reducing triggers that can exacerbate the condition. Custom fabricated occlusal orthotics or oral appliances can be used to stabilize the jaw and prevent locking. In more severe cases, treatments like Hyaluronic acid injections or Platelet-Rich Fibrin (PRF) injections may be recommended to promote healing, reduce inflammation, and lubricate the joint.

​​

Imaging and Diagnosis

​

Accurate imaging is vital to determine the underlying cause of jaw locking.

• MRI: Ideal for assessing soft tissue structures like the disc.

• CBCT Scan: Helps evaluate bony structures of the TMJ.

​​​

Get Help Today

Dr. Levi is one of 300 board-certified orofacial pain specialists in the United States. She sees patients both virtually and in-person. To make an appointment you can contact us here.​​​​