A locked jaw, medically known as trismus or sometimes jaw dislocation, occurs when the ability to open or close the mouth fully is severely restricted. This condition can be frightening, making speaking or eating difficult and painful. The restriction can be caused by muscle spasm, inflammation, or a mechanical issue within the joint itself. This guide provides information on immediate steps for temporary relief, explains the different causes, and outlines when and how to seek professional help.
Immediate Steps for Relief at Home
Applying moist heat is a simple way to help relax the involved muscles, such as the masseter and temporalis, by increasing blood flow to the area. A warm, damp towel or heating pad placed over the jaw joint for about 15 to 20 minutes can provide a comforting effect and potentially reduce muscle tension.
If movement is still possible, try very gentle, controlled jaw exercises, such as slowly opening the mouth only as wide as comfortable and moving the jaw slightly from side to side. It is important to stop any exercise immediately if it causes pain, as forcing the jaw can worsen the problem. Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, can help manage pain and reduce inflammation around the joint and muscles.
To minimize strain on the jaw while it is restricted, switch to a soft or liquid diet. Avoid chewy, hard, or crunchy foods that require extensive use of the jaw muscles, which can aggravate the condition. If the lock persists for more than a couple of days or pain increases, professional evaluation is necessary.
Understanding the Common Causes
A locked jaw often results from issues affecting the temporomandibular joint (TMJ). The most frequent mechanical cause is a temporomandibular disorder (TMD), which is often referred to as a “closed lock”. The articular disc, which acts as a cushion between the jawbone and the skull, can slip out of its normal position and block the joint from fully opening.
Muscle spasms often occur after prolonged jaw use, such as extensive dental procedures like wisdom tooth removal. This muscle-related restriction is known as trismus, and it is usually self-limiting, resolving within one or two weeks as the muscle inflammation subsides. Stress and teeth grinding (bruxism) also contribute to these spasms by causing chronic overuse and tension in the jaw muscles.
Less common, but more severe, causes involve infections and trauma. Infections, such as a peritonsillar abscess, can cause swelling and reflex spasms in the jaw muscles that restrict opening. The term “lockjaw” is also historically associated with tetanus, a rare bacterial infection that causes severe, sustained muscle contractions due to a neurotoxin. Finally, direct trauma to the jaw can cause a true dislocation, where the lower jawbone slips out of its socket completely, resulting in an “open lock” where the mouth cannot close.
When Emergency Care is Necessary
Certain signs indicate the need for immediate emergency care. A complete inability to move the jaw suggests a severe dislocation or a serious underlying pathology. This is considered a medical emergency because it prevents eating, drinking, and potentially interferes with airway management.
Emergency symptoms include high fever, severe swelling around the jaw or face, and difficulty swallowing or breathing. These symptoms may point to a rapidly progressing infection that requires immediate antibiotic intervention and possible drainage. If the jaw lock occurs immediately following a significant traumatic injury, such as a fall or accident, a fracture or severe dislocation must be ruled out by a medical professional.
Any jaw stiffness accompanied by recent, severe pain that radiates from the chest should also prompt an emergency call, as this can be an atypical symptom of a heart attack. Seeking immediate professional evaluation ensures that serious complications are addressed without delay.
Medical and Dental Treatment Options
The treatment approach depends entirely on the underlying cause. For a true jaw dislocation, where the joint is mechanically stuck in an open position, a physician or dentist performs a manual reduction. This procedure involves firmly manipulating the lower jaw to guide the condyle back into its socket in the skull.
For cases of trismus or TMJ-related closed lock, treatment is more conservative. Prescription medications, such as muscle relaxants or stronger anti-inflammatory drugs, may be used to break the cycle of muscle spasm and inflammation. Physical therapy, utilizing specific stretching regimens and exercises, improves the jaw’s range of motion and strengthens the muscles.
A dentist may prescribe a custom-fitted oral splint or bite guard to stabilize the temporomandibular joint and prevent excessive movement or clenching. For chronic muscle pain that does not respond to other treatments, injections of agents like Botox may be used to temporarily relax overactive jaw muscles. Rarely, if conservative management fails to resolve severe, chronic locking or if there is significant joint damage, surgical intervention may be necessary to repair or replace the joint structure.