The lower jaw (mandible) is a complex structure involving muscles, ligaments, and the two temporomandibular joints (TMJs) that enable speaking, chewing, and yawning. When discomfort arises on only one side, it suggests an asymmetrical issue affecting one of these components. This unilateral pain often signals a localized mechanical problem, a dental issue, or pain originating from a nearby structure. Understanding the exact source requires looking closely at the symptoms and their location.
Pain Originating in the Jaw Joint and Muscles
One-sided jaw discomfort frequently stems from a temporomandibular disorder (TMD). The TMJ acts as a sliding hinge connecting the jawbone to the skull. When the disc, cartilage, or associated ligaments on one side become damaged, inflamed, or misaligned, it disrupts the smooth movement of the jaw. This dysfunction results in localized pain near the ear and temple, limited ability to fully open the mouth, and mechanical noises like clicking or popping.
Muscle strain is another contributor to unilateral pain, often caused by teeth clenching or grinding (bruxism). This habit applies excessive pressure and constant strain to the jaw muscles, particularly the masseter and temporalis muscles. Chronic tension can lead to muscle spasms and soreness concentrated on one side of the face, especially upon waking. If a person favors one side for chewing or sleeps predominantly on one side, that side’s muscles and joint may experience greater strain, leading to asymmetrical symptoms.
Dental and Gum-Related Causes
Pain can arise directly from issues within the oral cavity, which is richly supplied with nerves. Severe tooth decay that penetrates the outer layers and reaches the sensitive inner pulp is a common cause of localized, intense pain. This discomfort is often aggravated by temperature changes or pressure from chewing, and it can radiate deep into the jawbone on the affected side.
A dental abscess, a collection of pus caused by a bacterial infection at the tooth’s root, causes severe, throbbing pain that extends throughout the jaw. This infection creates pressure within the bone or gum tissue distinctly felt on one side of the face. Similarly, the partial eruption or impaction of a lower wisdom tooth causes inflammation and localized pressure. Advanced periodontal disease (periodontitis) can also cause deep, aching pain perceived in the jawbone due to infection affecting the supporting tissues and bone.
Referred Pain from Nearby Structures
Sometimes, the source of jaw pain is not the joint, muscle, or teeth, but a nearby structure that shares nerve pathways. This is called referred pain, where the brain misinterprets the signal’s origin. The trigeminal nerve is responsible for sensation in the face and jaw, and issues along its branches can manifest as jaw discomfort.
Sinus infections (sinusitis) are a frequent cause of pain felt in the upper jaw, teeth, and cheek on one side. This occurs because the roots of the upper teeth sit close to the maxillary sinuses, and pressure from inflammation and fluid buildup can mimic a toothache or jaw pain. If the infection is limited to the sinuses on one side of the face, the pain will be localized to that side of the jaw. Less commonly, nerve disorders like trigeminal neuralgia cause brief, intense, electric-shock-like pain concentrated on one side of the face and jaw.
Knowing When to See a Professional
For mild, temporary jaw discomfort, conservative at-home care is often appropriate. This involves a soft food diet, gentle massage of the jaw muscles, and over-the-counter anti-inflammatory medications. Applying moist heat or cold packs to the painful area can also help reduce muscle soreness and inflammation. These self-care measures often resolve pain due to temporary muscle strain or sleeping in an awkward position.
However, certain signs indicate the need for professional evaluation by a dentist or physician. A consultation is warranted if the pain persists for more than a week, worsens over time, or significantly interferes with daily functions like eating or speaking. Immediate medical attention is necessary for emergency symptoms:
- The jaw locks in an open or closed position.
- There is intense swelling.
- The pain is accompanied by a fever, signaling a serious infection like an abscess.
- A sudden onset of severe jaw pain follows trauma.
- Pain radiates down the arm or chest, which can signal a serious medical event.