Pain experienced while chewing, known as masticatory pain, is a common symptom and a warning signal from the body. This discomfort can manifest in various ways, ranging from mild sensitivity to a severe, sharp jolt when pressure is applied. Chewing is a complex action involving teeth, gums, bone, joints, and muscles, meaning the source of the pain can originate from several distinct anatomical locations. Understanding the precise origin of the pain is the first step toward finding relief.
Causes Originating Within the Tooth Structure
The most immediate cause of chewing pain often lies within the tooth structure, particularly the hard enamel and the soft pulp beneath it. Dental decay, or a cavity, begins by dissolving the enamel’s mineral structure. Pain becomes pronounced once the decay penetrates the underlying dentin layer. When the cavity reaches the dentin, chewing pressure transmits forces directly to the sensitive pulp, which contains the tooth’s nerves and blood vessels.
A fractured or cracked tooth is another structural issue that can be challenging to diagnose because the crack may be nearly invisible. When biting down on a fractured cusp or crown, the chewing force causes the two segments of the tooth to momentarily separate. This movement irritates the internal pulp tissue, resulting in a sharp, immediate pain that disappears the moment pressure is released.
A deep cavity or crack can lead to pulpitis, which is inflammation of the inner pulp. The pulp may swell and become irreversibly damaged, often leading to necrosis or tissue death that requires a root canal procedure. Damaged or loose dental restorations, such as old fillings or crowns, also cause chewing pain. A filling that is slightly “high” creates a traumatic bite, leading to localized soreness from uneven pressure distribution during chewing.
Pain Due to Gum Disease and Supporting Tissue Issues
Pain during chewing can also signal problems in the periodontal tissues, which include the soft gums and bone anchoring the tooth in the jaw. Gingivitis is the earliest stage of gum disease, characterized by inflammation, redness, and swelling of the gums. This inflammation can make the tissue tender when food brushes against it. If gingivitis progresses to periodontitis, the infection begins to destroy the ligament and bone supporting the tooth root.
Degradation of the supporting structure leads to the formation of periodontal pockets around the tooth roots, accumulating bacteria and deepening the infection. As bone density decreases, the tooth loses its stable foundation, causing it to feel loose or tender when pressure is applied during chewing. The pain results from movement and pressure on the compromised support system, not the tooth structure itself. A periapical abscess is another source of pressure-related pain, forming a pus-filled sac at the tip of the tooth root. This infection creates swelling within the jawbone, resulting in a throbbing pain that intensifies when biting down on the affected tooth.
Problems with the Jaw Joint and Chewing Muscles
When pain is felt generally in the jaw, ear, or face during chewing, the temporomandibular joint (TMJ) and its associated muscles are often the source. Temporomandibular disorders (TMDs) encompass issues with the joint itself or the masticatory muscles controlling jaw movement. Chewing requires the smooth gliding and rotation of the jaw’s condyles. If the small disc within the joint is displaced or the joint is inflamed, movement can cause pain, clicking, or locking.
Muscular pain is often the most common form of TMD, arising from overuse or tension in the masseter and temporalis muscles. Habits like bruxism, or chronic teeth grinding and clenching, place excessive force on these muscles, leading to fatigue and localized pain when opening or closing the mouth. This tension can also refer a dull, aching sensation to the teeth or the side of the head, making chewing uncomfortable. Furthermore, a structural misalignment of the bite, or malocclusion, increases strain on the joint and surrounding muscles during mealtime.
Referred Pain from Non-Dental Sources
Sometimes, the sensation of a toothache when chewing is misleading because the actual problem lies outside the oral cavity. This phenomenon is called referred pain, where signals travel along shared nerve pathways and are interpreted by the brain as originating from a tooth or jaw. A common example involves the maxillary sinuses, which are air-filled spaces located above the upper back teeth.
When a person develops sinusitis, inflammation and pressure from fluid buildup in the sinus cavity can press on the nerve endings of the upper tooth roots. This pressure mimics a dull, aching toothache affecting several upper teeth, often intensifying when the head is lowered or tilted. Neurological conditions, such as trigeminal neuralgia, can also cause excruciating, short bursts of electric-shock-like pain in the face or jaw. Since the trigeminal nerve supplies sensation to the face and teeth, irritation can trigger pain from a simple touch or the act of chewing.