Cracked Tooth Syndrome: Diagnosis and Treatment

Cracked Tooth Syndrome is one of the most difficult diagnoses in dentistry because usually the dentist cannot see any problem with the tooth, either through a visual examination or on an X-ray. Here is the latest information on how to recognize and treat Cracked Tooth Syndrome (CTS).


Symptoms

  • You may feel a sharp pain when chewing in a particular area of your mouth. Usually, CTS is found on a back tooth. Lower second molars, followed by lower first molar and upper bicuspids, are the most commonly affected teeth. Your dentist will have you bite on a piece of wood, plastic or something firm to determine the correct tooth.

  • The pain is not accompanied by visible signs of problems. The affected tooth may have no fillings or decay, or it may have an intact filling with no visible problems.

  • Don’t mistake CTS for craze lines, which are tiny cracks that only affect the outer enamel of the tooth and are painless.

Causes

There are two major causes of cracked teeth:

  • Large fillings. Teeth with fillings are mechanically weaker, as there is less tooth structure available to hold the tooth together. If the filling involves more than 1/3 of the tooth, the tooth may have just 30% of its normal strength. Every time you eat, grind, or clench, the tooth will flex slightly. Over time, a hairline crack can develop at the bottom corner of the filling, like a crack in a car’s windshield. Silver amalgam fillings contain mercury that expands and contracts with temperature changes which further weakens the tooth.

  • Habits. Up to 80% of the population grinds or clenches their teeth when sleeping--these forces are up to ten times stronger than when eating! It’s not surprising that most people will say they were only eating only soft food when the tooth fractured. A history of trauma will also cause an increase in stress and strain, increasing the risk of CTS.

Why It Hurts

When you bite, your tooth flexes, which microscopically stimulates the nerve in the tooth. The hairline cracks open and close, applying pressure on tubules that run down the nerve, causing fluid to push and pull on the nerve. The nerve is also being exposed to bacterial toxins, allowing infection to spread to the nerve. Since the tooth cannot heal itself, the pain is always present whenever pressure is applied to the tooth. If the crack goes untreated, it will spread and deepen like a crack in glass and a part of the tooth may break off, causing a need for root canal therapy or extraction.


Treatment

It is recommended to treat CTS as soon as symptoms appear. The treatment will depend on the position and extent of the crack. Unfortunately, the tooth may still be lost eventually.

  • Small piece of tooth above the gumline: a simple restoration with a composite or porcelain filling may be all that’s needed.

  • Larger pieces of cracked tooth: a crown is needed. This will allow chewing forces to move the whole tooth rather than splitting it apart.

  • Crack breaks off below the gumline: periodontal surgery is necessary to expose the margin of the tooth so a crown can be placed.

  • Crack extends into the nerve of the tooth: root canal treatment is needed. About 10% of cracked teeth have nerves that can still die and will need this treatment, in addition to a crown.

  • Fractures that extend far down the middle of the tooth or are root fractures under the bone: usually cannot be repaired and the tooth will be removed.