A sudden, sharp discomfort in a back molar when biting down often points to a mechanical problem within the tooth structure. Unlike generalized tooth sensitivity, which reacts to temperature changes, pain triggered by chewing or pressure suggests the tooth is reacting to force. Molars are highly susceptible to these pressure-related issues because they bear the brunt of mastication. This pain signals that the integrity of the tooth has been compromised and requires professional attention.
Common Structural Causes of Chewing Pain
The most frequent mechanical cause of pain upon chewing is Cracked Tooth Syndrome (CTS), an incomplete fracture extending from the chewing surface. When pressure is applied during biting, the molar segments flex slightly, irritating the dental pulp, which contains nerves and blood vessels. The characteristic sharp, momentary pain of CTS is often most noticeable when the biting pressure is released, as the crack snaps back closed.
Molars are particularly vulnerable to CTS because they absorb the highest impact forces and often have large restorations that weaken the overall structure. The constant stress from teeth grinding (bruxism) or chewing hard objects can also initiate or propagate these cracks. Even if a fracture is not visible on a standard X-ray, pain upon biting strongly indicates the tooth is splitting under load.
Issues with existing dental work can also cause mechanical pain. A loose, broken, or cracked filling or crown exposes the sensitive underlying dentin or pulp to chewing forces. This movement allows bacteria or food particles to reach vulnerable inner tissues, resulting in a sharp jolt of pain.
A restoration that sits too high creates an uneven bite alignment. If a new filling or crown is slightly taller than surrounding teeth, it receives excessive force upon closure, placing undue pressure on the tooth and its supporting periodontal ligaments. This imbalance causes tenderness and pain until the surface is adjusted to match the natural bite.
When Pain Signals Deeper Internal Damage
Chewing pain can signal pathology that has extended beyond the outer layers into the internal pulp tissue. This internal inflammation, known as pulpitis, often results from deep decay or trauma that allows bacteria to irritate the nerve. Reversible pulpitis causes brief pain that disappears quickly after a stimulus is removed, allowing the pulp to heal. Irreversible pulpitis is more concerning.
Irreversible pulpitis presents with intense, lingering pain that persists for minutes after exposure to temperature changes or occurs spontaneously. When inflammation becomes severe, the tissue inside the tooth dies, and the infection can spread beyond the root tip. This leads to a dental abscess, a collection of pus and infected debris.
An abscess causes severe, constant, throbbing pain. Pressure from pus accumulation can make the tooth feel elevated in its socket. Chewing on an abscessed tooth is extremely painful because the force transmits directly to the infected area at the root tip. This condition often includes systemic symptoms like fever, facial swelling, or swollen lymph nodes, indicating a serious infection.
Immediate Relief and When to Seek Professional Help
While awaiting a dental appointment, temporary relief can be achieved through practical steps. Immediately avoid chewing on the affected side of the mouth to prevent further irritation or crack propagation. Taking an over-the-counter nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, helps reduce pain and accompanying inflammation.
Rinsing the mouth with a warm saltwater solution is beneficial for cleansing the area and soothing inflamed gums. Applying a cold compress to the outside of the cheek can temporarily numb the sensation and reduce swelling. These home remedies are strictly for symptom management and do not treat the underlying cause of the pain.
Certain symptoms indicate the need for immediate or emergency dental care. If the chewing pain is accompanied by swelling in the face, jaw, or neck, a high fever, or difficulty swallowing or breathing, the infection may be rapidly spreading. These signs require prompt professional intervention to prevent serious complications.
Typical Dental Treatments for Molar Pain
Definitive treatment for chewing pain is determined by diagnosing the underlying issue, typically involving dental X-rays and specialized bite tests. Pain caused by a high filling requires only a quick adjustment to reshape the restoration and restore proper bite alignment. Small fractures or minor decay may be treated with a simple filling or dental bonding to seal the exposed area.
If structural damage is more significant, such as a larger crack or extensive decay, a full-coverage crown is often necessary. The crown holds the compromised tooth structure together, preventing the crack from spreading when force is applied during chewing. This restoration protects the tooth and restores its functional strength.
For irreversible pulpitis or a dental abscess, the infection must be removed from the interior of the tooth via root canal therapy. The infected or dead pulp tissue is completely cleaned out, and the internal chamber is sealed. Following a root canal, a crown is almost always placed on a molar to protect the now-brittle structure from fracturing. Extraction is reserved for severe situations where the tooth is fractured too deep below the gum line and cannot be salvaged.