Cracked tooth: symptoms and treatment

Reviewed by Dr. Samar Fadavi, DDS

Short answer: A cracked tooth often causes a sharp pain when you bite down or release, and brief pain with cold. Cracks can be hard to see, so the dentist uses magnification, bite tests and x-rays to find them. Treatment depends on how deep the crack goes: bonding, a crown, a root canal or, for a split tooth, removal.

Why cracked teeth are easy to miss

Cracked teeth are common in adults, especially after age 40. Teeth flex a little every time we chew, and years of chewing, grinding and temperature changes can open tiny cracks. Unlike a broken tooth, a cracked tooth usually looks normal. The pain may come and go, appear only when you bite a certain way, and be hard to pin to one tooth. Many people chew on the other side for months before they mention it.

Finding a crack early matters, because cracks tend to grow. A crack caught while it is still in the crown of the tooth can often be protected with a crown. A crack that has travelled down into the root may mean the tooth cannot be kept.

This guide explains the types of cracks, the symptoms, what causes them, how the dentist finds them and the treatment options. It is general information for patients in Scarborough, the Danforth and East Toronto, not a diagnosis.

Types of cracks

Craze lines

Craze lines are tiny vertical lines in the outer enamel. Almost every adult has some, especially on the front teeth. They do not cause pain and usually need no treatment, although they can pick up stains.

Fractured cusp

A cusp is one of the pointed chewing bumps on a back tooth. A cusp can crack or break off, often around a large filling. It usually does not reach the nerve, so pain is mild. The tooth is often repaired with an onlay or a crown.

Cracked tooth

A crack runs from the chewing surface down toward the root. The tooth is still in one piece, but the crack can let bacteria in and can irritate the nerve. Early care can often save the tooth.

Split tooth

A split tooth is a cracked tooth that has separated into two parts. It usually cannot be saved whole, although part of it may sometimes be kept with a root canal and crown.

Vertical root fracture

This crack starts in the root and moves up toward the chewing surface. It may cause few symptoms until the gum or bone around it becomes infected. It is more common in teeth that have had root canal treatment. In most cases the tooth needs to be removed.

Symptoms of a cracked tooth

• Sharp pain when you bite down, or a sudden zing when you release the bite.
• Pain when chewing certain foods, such as nuts, seeds or crusty bread.
• Brief pain with cold food or drinks, sometimes with sweets.
• Pain that comes and goes, rather than a constant ache.
• Trouble telling which tooth hurts, upper or lower.
• Swelling of the gum around one tooth, if the crack has led to infection.

A crack that reaches the nerve can lead to lingering pain, throbbing at night and, in time, an abscess. Our guide on dental abscess signs explains those symptoms.

Cracked tooth or sensitive tooth?

Both can hurt with cold. Sensitivity from worn enamel or receding gums often affects several teeth and fades quickly. A cracked tooth usually affects one tooth, and pain with biting or release is the key clue. Our guide on sensitive teeth explains the other common causes.

What causes teeth to crack

• Grinding and clenching, often during sleep, puts heavy force on the back teeth.
• Large fillings leave less natural tooth to support the cusps.
• Chewing hard things, such as ice, popcorn kernels, hard candy, olive pits or pens.
• Sudden temperature changes, such as hot coffee followed by ice water.
• A blow to the mouth from a fall, sports or an accident.
• Root canal treated teeth without a crown, which can be more brittle.
• Age, because teeth carry decades of chewing force.
• An uneven bite that places extra load on one tooth.

What to do if you think a tooth is cracked

1. Book a visit soon. A cracked tooth is rarely a same-hour emergency unless there is severe pain or swelling, but early care gives the tooth a stronger chance.
2. Chew on the other side. Avoid biting on the sore tooth until it is checked.
3. Avoid hard and sticky foods. Skip nuts, ice, crusty bread, caramel and gum.
4. Avoid extremes of temperature. Let hot drinks cool and avoid ice-cold drinks on that side.
5. Manage pain safely. Over-the-counter pain medicine taken as directed can help. Ask a pharmacist if you take other medicines.
6. Note what triggers it. Tell the dentist which foods, temperatures or bite positions cause pain. These details help find the crack.
7. Wear your night guard if you have one, and mention grinding to the dentist if you think you clench at night.

What to avoid

• Do not keep testing the tooth by biting on it to see if it still hurts. Each test can deepen the crack.
• Do not ignore pain that comes and goes. Intermittent pain is typical of cracks.
• Do not chew ice or hard candy, or open packages with your teeth.
• Do not wait for swelling. Swelling means infection has started.

How the dentist finds a crack

Cracks are among the harder problems to diagnose, and the dentist may use several methods together:

• Your story. When it hurts, which foods trigger it and how long the pain lasts.
• Close examination with magnification and good light, sometimes after drying the tooth.
• Bite test. You bite on a small tool one cusp at a time to find the cusp that causes the pain.
• Cold test to see how the nerve responds.
• Light test. A bright light shone through the tooth can show a crack as a line where the light stops.
• Dye. A special dye can make a crack line easier to see.
• Gum check. A deep, narrow pocket beside one tooth can point to a crack in the root.
• X-rays and 3D imaging. Cracks often do not show on regular x-rays, but bone changes around a cracked root can. The clinic offers CBCT 3D imaging when more detail is needed.

Sometimes the crack is only confirmed when an old filling is removed and the dentist can see inside the tooth. Our guide on types of dental exams explains how different exams work.

Treatment options

Bonding

A small crack or chip in the enamel can be sealed or rebuilt with tooth-coloured bonding material. This is often done in one visit.

Onlay or crown

For a fractured cusp or a crack in the crown of a back tooth, an onlay or crown holds the tooth together and spreads chewing forces so the crack is less likely to grow. A temporary band or crown may be placed first to see whether the symptoms settle. Our crowns and bridges page explains how crowns protect weak teeth.

Root canal treatment

If the crack has reached the nerve and the pulp is inflamed or infected, a root canal is done before the crown. Our root canal treatment page explains this care.

Extraction

A tooth that has split into separate pieces, or has a crack running deep into the root, usually cannot be saved. It is removed and the space can later be filled with an implant, bridge or denture. Our guide on implants, bridges or dentures compares the options.

Monitoring

Craze lines and small cracks with no symptoms may only need watching at check-ups.

Will a crown always save a cracked tooth?

A crown greatly improves the odds, but cracks can sometimes keep travelling under a crown, and the nerve may still need a root canal later. The dentist will explain how likely that is for your tooth based on where the crack is and how far it goes. Choosing early treatment while the crack is small gives the tooth its strongest chance.

Living with a crown on a cracked tooth

• Brush and floss around the crown every day; the edge where it meets the tooth needs extra care.
• Wear a night guard if you grind.
• Keep avoiding ice and other very hard foods.
• Keep regular check-ups so the dentist can check the gum and the bite.

How to prevent cracked teeth

• Wear a custom night guard if you grind or clench. Our night guards and TMJ page explains how guards protect teeth.
• Wear a mouthguard for contact sports.
• Do not chew ice, popcorn kernels, hard candy, pens or fingernails.
• Ask about crowns or onlays for teeth with very large old fillings.
• Have a crown placed on back teeth after root canal treatment, as advised.
• Keep regular check-ups so early cracks and worn fillings are found.

Cracked teeth and older adults

Older adults often have many large fillings placed decades ago. The tooth around these fillings can crack under years of chewing. Dry mouth from medicines can also make decay around old fillings more likely, which weakens the tooth further. Regular exams catch these changes before a tooth splits. Our seniors’ dental care page explains care for older patients.

Grinding, clenching and cracks

Many people who crack a back tooth grind or clench without knowing it. Signs include a sore jaw or temples in the morning, flat or shiny worn spots on the teeth, small notches at the gum line, a partner hearing grinding at night and teeth that feel tired after sleep. Grinding can also crack fillings and crowns, not only natural teeth. If one cracked tooth is treated but the grinding continues, other teeth can crack in the same way, so the dentist may suggest a night guard as part of the plan.

The temporary crown test

When it is unclear whether a cracked tooth will settle once protected, the dentist may place a temporary crown or a snug band for a few weeks first. If the biting pain stops, a permanent crown is likely to work well. If the tooth stays sensitive or starts to ache, the nerve may already be inflamed, and root canal treatment can be done before the final crown. This step helps avoid surprises later.

Questions to ask at your visit

• Where is the crack, and how deep does it seem to go?
• Is the nerve healthy, or are there signs it is irritated?
• Would bonding, an onlay or a crown suit this tooth?
• What happens if I wait, and how quickly could it get worse?
• Do I show signs of grinding, and would a night guard help?
• Can you give me a written estimate and help me check my coverage?

When to see a dentist

Book a visit if:

• A tooth hurts when you bite down or let go.
• One tooth is sensitive to cold and the pain is sharp.
• You have started chewing on one side to avoid pain.
• You see a line in a tooth that was not there before.

Seek same-day care if pain becomes constant, keeps you up at night, or you notice swelling of the gum or face. Our emergency dentist page explains same-day visits.

Questions about cracked teeth

Can a cracked tooth heal on its own?

No. Unlike a broken bone, a crack in a tooth does not heal. Treatment aims to stop it from growing and protect the nerve.

Why does it hurt when I release my bite?

When you bite, the crack opens slightly. When you let go, it snaps closed, and fluid inside the tooth moves quickly, which the nerve feels as a sharp zing.

Why did the dentist not see the crack on my x-ray?

Most cracks run in a direction that x-rays cannot show. The dentist relies on bite tests, light, magnification and your symptoms.

Can a front tooth crack?

Yes, usually from a blow or biting something hard. Front tooth cracks are often treated with bonding, a veneer or a crown.

Is a cracked tooth an emergency?

Usually it is urgent rather than an emergency. Book soon. Swelling, constant pain or a tooth in pieces needs same-day care.

Will my insurance or CDCP help with a crown for a cracked tooth?

Many plans include crowns, but coverage depends on your plan. The team can help you check, and you will receive a written estimate before treatment.