Cracked Tooth Syndrome

How a cracked tooth causes pain

Teeth are made of hard enamel over softer dentin, which contains tiny fluid-filled tubules leading to the pulp (nerve). When a crack runs through the enamel into the dentin, biting forces flex the crack slightly open. Fluid inside the tubules moves, stimulating the nerve and causing a sharp jolt. The pain is often worse when you release the bite, because the crack snaps closed.

Over time, bacteria can travel down the crack, inflaming the pulp (pulpitis) and sometimes killing it, leading to a tooth abscess.

Symptoms

• sharp, brief pain when chewing, often on a specific food or at a certain angle
• pain on releasing the bite
• sensitivity to cold, sweet or, later, hot foods
• pain that comes and goes, sometimes for months
• difficulty pinpointing which tooth hurts, upper or lower
• avoiding chewing on one side

Constant or throbbing pain, especially at night, suggests the nerve is inflamed or dying.

Types of tooth cracks

Cracked tooth syndrome mostly refers to the "cracked tooth" stage, before it splits.

Causes and risk factors

• Tooth grinding or clenching (bruxism), often during sleep
• Large fillings that weaken the remaining tooth walls, often placed for tooth decay
• Biting hard objects: ice, hard candy, popcorn kernels, nuts, pens
• Previous root canal treatment without a crown
• Age: most common after 40, as teeth wear
• Sudden temperature changes, such as hot food then ice water
• Trauma to the jaw or face (see dental trauma)

Diagnosis

Cracked teeth are notoriously hard to find. A dentist or endodontist may use:

• detailed questions about which foods and bite positions cause pain
• bite tests: biting on a special tool one cusp at a time to reproduce the pain
• cold tests to check nerve health
• magnification and bright light, and transillumination (shining light through the tooth to show where it stops at the crack)
• dye to stain the crack
• removing an old filling to look directly
• X-rays, which usually do not show the crack itself but reveal bone loss or infection
• probing the gum around the tooth: a narrow, deep pocket can indicate a crack running toward the root
• cone-beam CT in some cases

Treatment

The aim is to stop the crack spreading and relieve pain.

• Crown: a full-coverage crown or onlay holds the tooth together, protects it from flexing, and relieves pain in most cases if the nerve is healthy. A temporary band or crown may be placed first to confirm the diagnosis.
• Bonded filling: for small cracks or a fractured cusp.
• Root canal treatment: if the pulp is inflamed or infected, followed by a crown.
• Extraction: if the crack extends deep into the root or the tooth has split. Replacement options include an implant, bridge or partial denture.

While waiting for treatment

• Chew on the other side.
• Avoid very hot, cold, hard and sticky foods.
• Use a toothpaste for sensitive teeth.
• Take ibuprofen or acetaminophen (paracetamol) if needed, following the label dose.

Prevention

• Wear a night guard if you grind or clench your teeth.
• Avoid chewing ice, hard candy, pens and popcorn kernels.
• Wear a mouthguard for contact sports.
• Ask your dentist about crowning teeth with very large fillings or after a root canal.

Outlook

Cracks do not heal on their own, and they tend to grow. When treated early with a crown, most cracked teeth are saved and become pain-free. The longer a crack is left, the more likely the nerve will be affected or the tooth will split.

Frequently asked questions

What are the symptoms of cracked tooth syndrome?

The classic symptom is a sharp, brief pain when biting down, especially when releasing the bite. Cold sensitivity is common. The pain often comes and goes and can be hard to locate. Constant pain suggests the nerve is affected.

Can a cracked tooth heal on its own?

No. Unlike bone, tooth enamel and dentin cannot repair a crack. Cracks usually spread over time. A crown or bonded restoration stops the crack from flexing and protects the tooth. Early treatment gives the best chance of saving it.

Why can't my dentist see the crack on an X-ray?

Most cracks run in the same direction as the X-ray beam and are too fine to show up. Dentists rely on bite tests, light, magnification, dye and sometimes removing old fillings to find them.

Does a cracked tooth always need a root canal?

No. If the nerve is healthy, a crown alone often relieves the pain. A root canal is needed if pain persists after a crown, if pain lingers after hot or cold, or if there are signs of infection.

What happens if a cracked tooth is not treated?

The crack can spread, the nerve can become inflamed or die, an abscess can form, or the tooth can split. A split tooth often has to be removed. Early treatment usually saves the tooth.