Cracked Tooth: Why It Hurts When You Bite and What to Do

You bite into something and feel a sudden, sharp jolt of pain. But it vanishes almost as quickly as it came. The tooth looks fine. Nothing appears broken. Yet the pain keeps returning unpredictably, sometimes with hot drinks, sometimes with cold, sometimes just from chewing. This frustrating pattern is the hallmark of a cracked tooth, and it is one of the trickiest conditions in dentistry to diagnose.

Types of Tooth Cracks

Not all cracks are the same. The type, location, and extent of the crack determine both the symptoms you experience and the treatment options available.

Craze Lines

These are tiny, superficial cracks in the outer enamel only. They are extremely common in adults and are usually harmless -- they don't cause pain and don't require treatment. You may notice them as fine lines on your front teeth, particularly under certain lighting. Nearly all adult teeth develop craze lines over time.

Fractured Cusp

A cusp is one of the raised points on the biting surface of a tooth. A fractured cusp occurs when a piece of the chewing surface breaks off, often around an existing large filling. This type of crack typically doesn't affect the nerve and may cause little or no pain, though the tooth may feel rough or sharp. Treatment usually involves a crown to restore the tooth's shape and strength.

Cracked Tooth (Cracked Tooth Syndrome)

This is the type that causes the classic intermittent pain on biting. The crack extends from the chewing surface vertically towards the root, but the tooth is still in one piece -- it hasn't separated. When you bite, the crack flexes open slightly, stimulating the nerve. When you release, the crack snaps shut, causing a characteristic sharp "rebound" pain.

If the crack extends into the pulp (the nerve and blood supply inside the tooth), the tooth may become sensitive to temperature, develop a persistent ache, or become infected. Early treatment is critical -- once the crack reaches the pulp, a simple crown may no longer be sufficient and root canal treatment may be needed.

Split Tooth

A split tooth is the end stage of an untreated cracked tooth. The crack has progressed through the entire tooth, separating it into two distinct segments. A split tooth cannot be saved intact. Depending on the position of the split, it may sometimes be possible to save one portion, but in many cases the tooth will need to be extracted.

Vertical Root Fracture

Unlike other cracks that start from the chewing surface, a vertical root fracture begins in the root and propagates upward. These are particularly tricky because they may cause minimal symptoms initially -- sometimes just mild discomfort and slight swelling near the gum. Root fractures are more common in teeth that have previously had root canal treatment. Unfortunately, vertical root fractures usually require extraction.

Need to find a dentist who can see you quickly? Search for available appointments near you.

Symptoms to Watch For

• Sharp, fleeting pain when biting or chewing that may be hard to localise
• Pain on releasing a bite -- this "rebound pain" is particularly characteristic
• Sensitivity to hot, cold, or sweet foods and drinks
• Intermittent, unpredictable pain that comes and goes
• Discomfort that is hard to pinpoint -- you may not be sure which tooth is causing the problem
• Swelling of the gum around the affected tooth

Why Cracks Are Hard to Diagnose

Cracked teeth are notoriously difficult to detect, even for experienced dentists. Here's why:

• Cracks often don't show on X-rays. Standard dental radiographs capture images in two dimensions, but cracks typically run in the plane of the X-ray beam, making them invisible. Even advanced imaging may miss fine cracks.
• The pain can be referred. You may feel pain in a neighbouring tooth or even in the opposite jaw, making it hard to identify the culprit.
• Symptoms are intermittent. The crack may only hurt when biting at a specific angle, so it may not be reproducible during a dental examination.

Your dentist may use several techniques to identify a crack: a bite test (asking you to bite on a special stick one cusp at a time), transillumination (shining a bright light through the tooth -- cracks block the light), dental dyes that highlight crack lines, or magnification loupes. In some cases, removing an old filling may be necessary to visualise a crack directly.

Treatment by Crack Type

Crown

For a cracked tooth that hasn't reached the nerve, a dental crown is often the treatment of choice. The crown acts as a protective cap, holding the tooth together and preventing the crack from spreading further. This may resolve the symptoms entirely if the nerve inside the tooth is still healthy.

Root Canal Treatment

If the crack extends into the pulp, or if the nerve has become inflamed or infected, root canal treatment may be needed. This involves removing the damaged nerve tissue, cleaning the root canal system, and sealing it. The tooth will then typically need a crown for long-term protection. Modern root canal treatment is generally comfortable with local anaesthetic.

Extraction

If the crack extends below the gumline, through the root, or if the tooth has split completely, extraction may be the only viable option. Replacement options include dental implants, bridges, or dentures, depending on the location and your preferences.

Don't Delay Treatment

One of the most important things to understand about cracked teeth is that cracks do not heal on their own. Unlike bone, tooth structure cannot regenerate. A crack will typically worsen over time as ongoing biting forces stress the fracture line. What might be treatable with a crown today could become a root canal case next month, or an extraction in six months.