A sharp, localized pain when pressure is applied to a tooth, such as when biting down or chewing, is a specific warning sign about your oral health. This discomfort, often described as a sudden jolt or acute ache, suggests a mechanical or pressure-related issue directly aggravated by the force of your bite. Unlike a dull, constant ache that might indicate a generalized infection, pain on biting signals a localized problem requiring professional diagnosis and treatment.
Structural Damage to the Tooth
One of the most common causes of pain when biting is a compromise to the physical structure of the tooth, often due to microscopic breaks or fractures. This condition, frequently termed Cracked Tooth Syndrome (CTS), involves an incomplete fracture line often too small to be seen on an X-ray. When you bite down, the pressure forces the two segments of the tooth apart, irritating the internal pulp tissue and resulting in sharp, fleeting pain.
Sometimes the most intense pain is felt when the pressure is suddenly released, known as “rebound pain.” Fractured cusps, the pointed chewing surfaces of the back teeth, can also cause acute pain when biting down, particularly on hard or sticky foods. This fracture usually occurs around an existing filling and exposes the underlying sensitive dentin.
A failing or improperly sealed dental restoration, such as an old filling or a crown, can also lead to biting pain. If a filling is loose or if decay has developed underneath it, bacteria and pressure can irritate the tooth’s internal nerve. A filling that is slightly “too high” results in an uneven bite, causing disproportionate force on that single tooth and leading to localized discomfort. This uneven pressure can be corrected by a dentist.
Deep Nerve Inflammation
Pain on biting can also be a symptom of conditions related to the internal tissue of the tooth, known as the dental pulp, which contains the nerves and blood vessels. When decay or trauma reaches the pulp, it causes inflammation called pulpitis. In its early, reversible stage, the pain is typically a short-lived sensitivity, but pressure from biting can still cause discomfort as the inflamed tissue is compressed.
If the inflammation is severe, it progresses to irreversible pulpitis, where the pulp tissue is dying or already dead. While this stage is often associated with spontaneous, lingering pain, pressure from chewing can still manifest as discomfort.
A periapical abscess, a collection of pus and infection at the tip of the tooth root, is another serious cause of pain when biting. The infection spreads from the pulp and creates a pocket that pushes the tooth slightly out of its socket. When you bite down, this pressure is applied directly onto the inflamed tissue and bone, causing severe, localized pain and making the tooth feel “high” or elevated.
Issues with Surrounding Tissues
The pain experienced when biting does not always originate from the tooth itself but can stem from the supporting structures that hold it in the jawbone. Each tooth is anchored by the periodontal ligament (PDL), a sensitive tissue that acts like a shock absorber. Trauma, such as clenching, grinding (bruxism), or biting down suddenly on something hard, can sprain or bruise this ligament, sometimes called “sprained tooth syndrome.”
When the PDL is inflamed, the tooth becomes tender to pressure, creating a dull ache or sharp pain when biting. This soreness often resolves with rest. Advanced gum disease, or periodontitis, can also contribute to biting pain by weakening the bone and support structures, allowing the tooth to shift slightly under the force of chewing.
In some cases, pain in an upper back tooth may be referred pain from a different source. The roots of the upper back teeth are anatomically close to the maxillary sinuses. A sinus infection or severe congestion causes fluid and pressure buildup, which can irritate the nerves supplying those teeth, mimicking a toothache when pressure is applied.
What to Do Next
If you experience pain when biting, the most important action is to schedule an examination with a dental professional immediately, as this symptom rarely resolves on its own. While awaiting your appointment, avoid chewing on the affected side of your mouth to prevent further irritation or potential fracture. You may gently rinse your mouth with warm salt water several times a day to help soothe inflamed gum tissue.
For temporary relief, over-the-counter anti-inflammatory medications may help manage the pain and swelling. Seek immediate care if the pain is persistent, severe, or accompanied by signs of a serious infection, such as fever, visible swelling of the face or jaw, or an inability to close your mouth fully. A dentist must accurately diagnose the underlying cause to determine the correct course of treatment.