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# Cracked tooth and vertical root fracture

- Oral pathology

A cracked tooth hurts sharply on biting, often when the bite is released. Cracks grow, and a crack that splits the root usually means losing the tooth.

Updated Nov 12, 2026

## Key points

- Pain on biting release suggests a crack.
- Radiographs usually miss cracks: bite test and transillumination.
- Vertical root fracture means extraction, as a rule.

## What it is

Cracks run from harmless enamel craze lines to cracks into dentine and pulp, split teeth and vertical root fractures. A cracked tooth is typically a lower molar or upper premolar with a large filling, in someone who clenches or grinds. The crack flexes on biting, moving fluid in the dentine, which causes sharp, brief pain. Vertical root fractures usually occur in root-filled teeth, especially with posts.

## How to recognise it

- Classic symptom: sharp pain on biting on a particular cusp, often on release of the bite; sensitivity to cold.
- Tests: biting on a bite stick cusp by cusp, transillumination, dye and magnification; cracks rarely show on radiographs.
- Craze lines (enamel only) are normal and need no treatment.
- Vertical root fracture: a narrow deep pocket, a sinus tract close to the gum margin and a J-shaped radiolucency along the root.
- Risk factors: large fillings, root canal treatment without cusp coverage, posts, bruxism and chewing hard objects.

## Differential and risks

- An early crack is protected with cusp coverage (onlay or crown) to stop it growing; if the pulp is affected, root canal treatment too.
- A crack extending deep under the gum or through the root floor has a poor prognosis.
- A vertical root fracture cannot be repaired predictably: the tooth or root is usually extracted.

## Next step / Initial management

- Pain on biting with a normal radiograph: suspect a crack and do a bite test cusp by cusp.
- Suspected crack: refer to the dentist promptly for cusp protection before it propagates; a temporary band or crown may be used.
- Root-filled tooth with a narrow deep pocket or sinus tract near the gum: refer for assessment of vertical root fracture.

## Test yourself

Think of the answer, then tap the question to see it.

## What symptom is typical of a cracked tooth?

Sharp pain on biting on a cusp, often when the bite is released.

## Why are radiographs of limited use for cracks?

Cracks are thin and usually run parallel to the X-ray beam, so they rarely show until bone is lost.

## What is the usual outcome of a vertical root fracture?

Extraction of the tooth or the affected root, because it cannot be repaired predictably.

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## Connections

## Related 5

- [Broken and displaced teeth: fractures and luxations](https://durgical.com/en/dentistry/broken-and-displaced-teeth-fractures-and-luxations/)
- [Why fillings fail: secondary caries, fracture and leakage](https://durgical.com/en/dentistry/why-fillings-fail-secondary-caries-fracture-and-leakage/)
- [Endodontic–periodontal lesions](https://durgical.com/en/dentistry/endodontic-periodontal-lesions/)
- [Restoring the root-filled tooth: cusp coverage and posts](https://durgical.com/en/dentistry/restoring-the-root-filled-tooth-cusp-coverage-and-posts/)
- [Tooth wear and sensitivity: erosion, attrition, abrasion and bruxism](https://durgical.com/en/dentistry/tooth-wear-and-sensitivity-erosion-attrition-abrasion-and-bruxism/)

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Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.

Sources: [Cracked Tooth Syndrome](https://www.ncbi.nlm.nih.gov/books/NBK606115/) (StatPearls Publishing (NCBI Bookshelf), 2024); [Tooth Fracture](https://www.ncbi.nlm.nih.gov/books/NBK551650/) (StatPearls Publishing (NCBI Bookshelf), 2025); [True vertical tooth root fracture: Case report and review](https://pmc.ncbi.nlm.nih.gov/articles/PMC3214543/) (Contemporary Clinical Dentistry (PMC open access), 2011).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/dentistry/cracked-tooth-and-vertical-root-fracture/