Question: Why does my tooth hurt when I bite, even though nothing shows up on an X-ray?
Explanation: Cracked tooth syndrome describes the symptoms arising from an incomplete fracture in a tooth, typically a molar. The hallmark is sharp pain on releasing a bite rather than on applying pressure, as the crack momentarily opens and fluid moves within the dentinal tubules. Cold sensitivity is common. Cracks run in the same direction as the X-ray beam and are essentially invisible on standard radiographs. Diagnosis relies on bite tests, transillumination, and dye staining. Treatment usually means a full-coverage crown to hold the tooth together, sometimes preceded by root canal treatment.
Related Questions:
Why does it hurt when I let go of a bite rather than when I bite down?
Biting compresses the crack closed. Releasing allows it to spring open, causing sudden fluid movement in the dentinal tubules, which stimulates the pulp nerves. This release pain is so characteristic that dentists test for it deliberately using a bite stick on individual cusps.
Why can’t the dentist see the crack on an X-ray?
Cracks in molars typically run mesiodistally, in the same plane as the X-ray beam. Radiographs detect changes in density across a beam path, not features parallel to it. Transillumination, methylene blue dye, and removing the existing filling reveal cracks far more reliably.
Will a crown definitely fix a cracked tooth?
It resolves symptoms in the majority of cases by preventing cusp flexure. However, if the crack has already reached the pulp, root canal treatment is needed first. If it extends below the bone level, the outlook is poor regardless of restoration.
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