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Cracked Tooth — Causes and Treatment

A cracked tooth is one of the trickier dental problems to diagnose because cracks are often invisible to the naked eye. The symptoms — sharp pain on biting, sensitivity to cold, a feeling that something is wrong but you cannot pinpoint where — are usually the first clue. Most cracks can be managed if they are caught early; deeper cracks need different planning.

If you think you may have a cracked tooth, it is worth booking a check sooner rather than later — cracks tend to progress. You can book online at a time that suits you.

Common symptoms of a cracked tooth

  • A sharp, brief pain when you bite down on a particular tooth
  • Discomfort when releasing the bite, more than when biting down
  • Sensitivity to cold that lingers a few seconds longer than expected
  • A feeling that one tooth is "not quite right" without obvious decay
  • Pain triggered by certain textures — crunchy food, seeds, ice
  • Episodes of pain that come and go, sometimes weeks apart

Cracked teeth can be hard to identify because the symptoms come and go. You may have a flare-up after biting something hard, then nothing for weeks. That intermittent pattern is itself a useful clue.

Types of cracks

Craze lines

Craze lines are tiny, shallow surface cracks in the enamel. They are very common in adult teeth, are not usually painful, and do not need treatment. Your dentist may simply note them.

Fractured cusp

A cusp is one of the pointed parts of a back tooth. A fractured cusp is a piece of the chewing surface breaking off, often around an older filling. These are usually straightforward to manage with a new filling, an onlay, or a crown.

Cracked tooth (cracked tooth syndrome)

This is the classic crack that runs through the chewing surface and may extend toward the root. The tooth is intact, but the crack flexes when you bite, which is what causes the sharp pain on release. Treatment depends on how far the crack extends — often a crown to hold the tooth together, sometimes root canal treatment if the nerve is involved.

Split tooth

A crack that has progressed completely through the tooth, splitting it into separate pieces. Split teeth usually cannot be saved as a whole, although in some cases one half can be kept.

Vertical root fracture

A crack that starts at the root and travels upward. Vertical root fractures are usually painful, may cause an abscess on the gum, and typically need extraction of the tooth.

What causes a tooth to crack

Teeth crack for a range of reasons, often a combination of factors over time:

  • Biting on something hard — ice, seeds, popcorn kernels, bones, fingernails, pens
  • Grinding and clenching — bruxism puts heavy repeated loads on the teeth, particularly the back ones
  • Large old fillings — when there is not much natural tooth left around a filling, the remaining walls can crack
  • Sudden temperature change — eating something very hot then immediately drinking something cold
  • Trauma — a knock, fall, or sporting injury
  • Age-related wear — older teeth that have been heavily restored are more prone to cracking
  • Misaligned bite — teeth that take more load than others wear and crack first

How a cracked tooth is diagnosed

Diagnosing a cracked tooth often takes a combination of clues. Your dentist may:

  • Ask you to bite on a small block in different positions to identify which cusp triggers the pain
  • Use a cold test to check the nerve
  • Look for staining along the crack with magnification and good lighting
  • Take targeted digital X-rays — cracks themselves rarely show on X-ray, but X-rays show changes around the root
  • Remove an old filling and inspect underneath if needed

Sometimes the diagnosis becomes clearer once a filling is removed and the dentist can see what is happening underneath. This is normal — cracks hide.

Treatment options

The right treatment depends on how deep the crack is and whether the nerve is involved.

Bonding or a new filling

For very shallow cracks or fractured cusps, a bonded composite filling can stabilise the tooth.

Onlay or crown

For most cracked teeth, a crown is the most predictable way to hold the tooth together. It wraps around the tooth and absorbs the biting forces that were causing the crack to flex. An onlay is a similar idea, covering one or more cusps without needing to wrap the whole tooth — see our information on inlays and onlays.

Root canal treatment

If the crack extends into the nerve, the tooth may need root canal treatment before a crown is placed. This is more common in cracks that have been left untreated and have progressed.

Extraction

Where a crack has split the tooth or extends down into the root, extraction is usually the only option. Once healed, you can consider implants or bridges to replace the tooth.

Treating the underlying cause

If grinding or clenching contributed to the crack, a nightguard is usually part of the plan to protect the rest of the mouth.

Why early action matters

Cracks tend to progress when they are left untreated, particularly under heavy chewing forces. What starts as a tooth that can be saved with a crown can, over months, become a tooth that needs root canal treatment, and eventually one that needs extraction. Catching the crack early usually means simpler treatment and a better chance of keeping the tooth.

What to expect at your appointment

A cracked-tooth visit usually takes 30 to 45 minutes. We will go through your symptoms, examine the tooth with magnification, take any imaging that is helpful, and then talk through the options. In many cases we can place a temporary cover at the first visit to settle symptoms while a crown is being made.

Who this may suit

This page is relevant if you have noticed sharp pain on biting, intermittent pain that has come and gone, or a feeling that one tooth is not quite right after biting something hard. It is also relevant if you grind or clench your teeth and want to understand the risks. Older patients with multiple large fillings are particularly worth being aware of cracks.

Health funds and payment

Fillings, onlays, crowns, and root canal treatment all have specific item numbers under most policies. We are HICAPS providers and can claim your eligible rebate on the day. The amount you receive depends on your individual policy, your level of cover, and your annual limits — your fund can confirm before your appointment. See major dental cover for more on crowns and similar treatments.

Cracked tooth FAQs

Why do cracks not show on X-rays?

Cracks usually run vertically through the tooth, which is the same direction an X-ray beam travels. You only see a clear line on an X-ray if the crack widens. We look for cracks visually and with bite tests, and X-rays help rule out other causes.

Can a cracked tooth heal on its own?

No. Teeth do not heal cracks the way bones heal fractures. The aim of treatment is to hold the crack stable and stop it progressing.

Will I definitely need a crown?

For most cracks that go beyond the surface, a crown or onlay is the most predictable way to stabilise the tooth. Shallow cracks may be managed with bonding, and very deep cracks may need root canal or extraction. Your dentist will explain which category your tooth falls into.

How long can I leave it?

The longer a crack is left, the more it tends to progress under chewing. If symptoms are intermittent, it is still worth booking a check soon rather than waiting for a flare-up.

Can a cracked tooth be saved if it goes into the root?

Usually not. Vertical root fractures and split teeth are rarely savable, although your dentist will assess each case individually.

Does a crown guarantee the tooth is fine forever?

No. A crown is the most reliable way to stabilise a cracked tooth, but if the crack has already extended into the nerve or root, the tooth may still need further treatment later. We are upfront about this when planning a crown for a cracked tooth.

I clench my teeth at night. Will a nightguard help?

It can significantly reduce the loads that cause cracks in the first place. A custom nightguard is usually a good investment if you are a known grinder, particularly if you have already had a cracked tooth.

Related information

Book a cracked-tooth assessment

If you suspect a cracked tooth, the sooner we can take a look, the more options you usually have. Book online or phone the practice during business hours.