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A cracked tooth can be a harmless line in the enamel, a corner that will eventually break off and be repaired, or a fracture heading below the gum where the tooth cannot be saved. The direction, depth and position of the crack decide which. A chip is different: a piece has already broken away, and it is repaired with bonding or a crown. Cracks are often missed because the pain comes and goes and nothing shows on an X-ray, so if a tooth has been bothering you on and off for weeks, say so.
Chip or crack?
A chip is a piece of tooth that has already broken away: a corner off a front tooth, an edge worn and fractured, a cusp off a molar. A crack is a fracture line in a tooth that is still whole, and it can grow. Chips are usually obvious. Cracks are often invisible and show up as symptoms.
Signs of a cracked tooth
- Pain when biting, particularly on letting go
- A sharp sensitivity to cold that comes and goes without a cavity to explain it
- Pain that is hard to pin to one tooth, often only with certain foods or at a certain angle
- A tooth that aches after chewing something hard
- No symptoms at all, with the crack spotted at an examination
Because the pain is intermittent and the crack hard to see, cracked teeth are often misdiagnosed or dismissed.
Types of crack
Craze lines are shallow lines in the enamel, very common in adults, visible as faint vertical marks. They are harmless and need no treatment.
A fractured cusp is a crack around a corner of a back tooth, usually beside a large filling. It tends to break off cleanly and painlessly, and the tooth is then restored, often with a crown. It is a nuisance rather than a danger.
A cracked tooth proper runs from the chewing surface toward the root. It may be stable for a long time, but cracks tend not to stop growing, and if it reaches below the gum line the tooth is usually lost.
A split tooth is a cracked tooth that has gone all the way: the two halves move independently. It cannot be saved as a whole, and the usual outcome is extraction and replacement.
A vertical root fracture starts in the root and travels upward, often in a tooth that had a root canal years ago. It is hard to detect, usually shows as a recurring gum infection beside the tooth, and generally means extraction.
How we find a crack
- Looking closely with magnification is the most useful test.
- A fiber-optic light shone through the tooth can reveal a crack as a line that stops the light.
- A bite test, biting on a small device tooth by tooth, reproduces the pain on release and tells us which cusp is involved.
- Cold testing shows whether the nerve has been affected.
- X-rays rarely show the crack itself but show what else is going on.
- A 3D scan sometimes helps with a suspected root fracture.
Our diagnostics page covers these tests.
What the repair looks like
A chipped edge or corner on a front tooth is rebuilt with composite bonding, matched to the tooth and shaped in the chair, usually in one visit. A larger chip on a back tooth may need a crown.
A cracked tooth with a healthy nerve is covered with a crown, which binds the tooth together and stops the crack opening under chewing forces. Done before the crack reaches the gum, this is far less expensive than losing the tooth, and the crown goes on a living tooth in the great majority of cases.
A crack that has reached the nerve needs a root canal as well as a crown, provided the crack has not travelled below the point where the tooth can be saved.
A split tooth or a cracked root is removed, with a plan made beforehand for the space: often an implant, sometimes a bridge.
Protecting the rest of your teeth
If you crack one tooth, the cause matters.
- Grinding and clenching at night load the teeth with forces they were not built for, and a custom night guard takes that load instead.
- Large old fillings leave thin walls of tooth that eventually give, and crowning those teeth before they break is often the right plan.
- Ice, popcorn kernels, olive pits and using teeth as tools are the usual causes of a sudden crack in an otherwise healthy tooth.
Frequently asked questions
My tooth hurts when I bite and then let go. Is it cracked?
That pattern, pain on release more than on pressure, is the classic sign of a cracked tooth. It is not the only cause, so we confirm it with a bite test on each tooth and a close look with light and magnification.
Can a cracked tooth heal?
No. Tooth structure does not knit back together. A crack can stay stable for years or progress; the treatment is to stop it progressing, usually by covering the tooth with a crown before it splits.
Will the crack show on an X-ray?
Rarely. Most cracks run in directions X-rays cannot see. We find them by looking, by shining a light through the tooth, and by reproducing the pain with a bite test. Even then the full depth is not always knowable in advance.
I chipped a front tooth. Can it be fixed the same day?
Usually. A chipped edge or corner is rebuilt in the chair with composite bonding, matched to the tooth, often in one visit and often without anesthesia. Bring the piece if you have it.
Why do my teeth keep cracking?
Grinding and clenching are the usual reason, along with large old fillings that leave thin walls of tooth around them. A night guard protects against the first; crowning heavily filled teeth before they break addresses the second.
