Our teeth are located on two separate jaws: the upper jaw (maxilla) and the lower jaw (mandible). The upper jaw is fixed in place. However, the lower jaw has an articulating joint with the temporal bone of the skull. This joint is technically referred to as the temporomandibular joint (abbreviated as TMJ). Movements of the lower jaw at the temporomandibular joint allow us to perform activities such as talking and chewing food.
Pain in the lower jaw is a common occurrence. One of the most common reasons is toothache caused by decay of teeth that are located in the mandible. A physical blow to the face may also cause trauma and pain in the region of the lower jaw. Lower jaw pain could also arise from other structures that are located in close proximity to the mandible, such as the tongue, submandibular salivary gland, parotid salivary gland, and cheeks.
In some cases, lower jaw pain could even be caused by a serious heart problem (like a heart attack). When the lower jaw pain keeps worsening and is accompanied by difficulty in opening the mouth, facial swelling, dizziness, and chest pain, one should seek immediate medical attention.
Causes of Pain in the Lower Jaw
As mentioned previously, not all sources of pain in the lower jaw reside in the mandible. Lower jaw pain could arise from other structures such as the teeth, gums, temporomandibular joint, salivary glands, muscles of the jaw, and heart. The following are some of the most frequent causes of lower jaw pain.
Read more on tight jaw muscles.
Fracture of jaw bone
A break in the lower jaw bone could occur due to trauma caused by physical assault, motor vehicle accidents, sports injuries, and falls. Both men and women are equally susceptible to having fractures of the jaw bone. However, due to the more aggressive nature of the causes, the incidence of fractured lower jaw is 3 times higher in men than in women. The mandible may undergo a simple fracture, comminuted fracture or a compound fracture.
In a simple fracture, the bone does not fragment after the break, and there is no penetration of the broken bone into the skin and other tissues. In a comminuted fracture, the bone breaks into more than two fragments. In a compound fracture, the broken ends of the bone pierce the skin and other nearby tissues. Fracture of the lower jaw is typically characterized by tenderness and excruciating pain that worsens during any jaw movements. This makes activities such as speaking, eating, or just opening the mouth very painful.
There may also be visible bruising and swelling in the fractured region. The face may also get deformed around the fractured lower jaw. In cases of compound fracture of the mandible, bleeding may occur on the overlying skin or from the inside surface of the mouth.
Dislocation of the lower jaw
Dislocation of the lower jaw refers to a condition in which the mandible disconnects with (or slips out of) the temporomandibular joint. Trauma caused by a significant blow to the face or a chronic joints problem could lead to dislocation of the lower jaw. In some cases, the mandible may slip back into the temporomandibular jaw on its own. In other cases, medical intervention may be required to put the lower jaw back into its original position.
Moving the dislocated jaw may produce an audible clicking or popping sound. Like in a fracture, tenderness, pain, and deformity typically occur with a dislocated jaw. However, unlike in a fracture, bleeding is not usually present in joint dislocation.
Problems with teeth
One of the most common causes of lower jaw pain is tooth decay (also known as dental caries). Tooth decay occurs when the outer layer of enamel wears down and a cavity forms in the tooth. Food particles and bacteria get lodged within this cavity, resulting in gradual deterioration of the tooth. The resultant tooth infection causes pain that intensifies with time. Apart from tooth decay, a broken tooth could also cause pain in the lower jaw. The pain caused by broken tooth appears immediately.
Dental abscess refers to pus formation in or around a tooth. Also known as dentoalveolar abscess, a dental abscess may occur in different regions of the tooth or the surrounding tissues. The most common types of dental abscess are periapical abscess and periodontal abscess. Tooth decay or broken tooth are frequently the cause of dental abscess. In some cases, the abscess may be invisible and painless. Facial swelling on the affected side may occur.
Impaction of teeth
An impacted tooth refers to a tooth that is unable to come out of the gums due to physical interference caused by surrounding teeth. The wisdom teeth (third molars) are the most frequently impacted teeth as they come out well after the other permanent teeth in the mouth. Depending on the location, an impacted teeth can cause both upper and lower jaw pain. Impaction may either be partial or full.
Only the crowns of partially impacted teeth are visible above the gums. Fully impacted teeth fail to emerge out of the gums, and are not visible from outside. Painful symptoms arise mainly upon infection of the impacted tooth, or damage to an adjoining tooth.
Apart from pain, symptoms caused by impacted tooth include redness and swelling in the gums, bleeding from the gums, swelling on the affected side of the face, headaches, bad breath (technically referred to as halitosis), and bad taste sensation in the mouth (technically referred to as cacogeusia).
Some of the most serious causes of lower jaw pain are angina pectoris and myocardial infarction (commonly referred to as heart attack). Both these heart problems are caused by reduced blood supply to the cardiac muscles (usually caused by narrowing or complete blockage of coronary arteries). Heart muscles die when starved of blood supply. This causes the symptoms of the heart attack.
Even though people mostly think of pain in the chest and the left arm as the main symptoms of heart attack, jaw pain is also a common feature of this condition. Difficulty in breathing, dizziness, excessive sweating, nausea and vomiting may also occur in a heart attack. It is important to get prompt treatment when these symptoms are present because heart attacks can be lethal within minutes.
Other causes of lower jaw pain
Joint problems (such as arthritis and synovitis) can cause lower jaw pain by affecting the temporomandibular joint. Inflammation of the salivary glands could also cause lower jaw pain. Some other potential causes of lower jaw pain include ear problems, gingivitis, lockjaw, fibrous dysplasia of mandible, and cancer.
Read more on cervicogenic facial pain.