Cracked tooth: common causes

Generally, teeth are quite durable, designed to hold up to daily crunching, biting, and chewing of all kinds of solid foods. Sometimes, however, a one-off incident like a fall or blow to the mouth – or a chronic condition like nighttime teeth grinding – can generate enough force that a tooth becomes cracked or fractured.

People with a history of tooth decay, large dental fillings, and root canal treatment may also be more susceptible to a fracture.1 Want to learn how to avoid a cracked tooth? Read on for some of the most common causes.

Do you think you may already have a cracked tooth? Make an appointment with your dentist as soon as possible.


Common causes of a cracked tooth

A cracked tooth can be the result of many possible incidents. In some cases, you may have little idea what caused the fracture, especially if it happens overnight as a result of teeth grinding (bruxism) or if it forms gradually over time. The following are the most common causes of a cracked tooth:

  • Teeth grinding: Chronic teeth grinding, also known as bruxism, can cause cracked teeth due to repetitive stress and friction. Since teeth grinding often occurs during sleep, individuals may not be aware that it’s happening – thus leading to “mystery” cracks in teeth. These cracks may start out as minor stress fractures but can become more significant and painful over time if the root cause is not corrected.
  • Weak teeth: Weak teeth, characterized by long-term wear or erosion of enamel, or lost tooth structure from large fillings, are far more susceptible to cracks. This is due to a deficient tooth structure, unable to withstand the normal rigors that teeth endure. With this weakened tooth structure, cracks and fractures may occur more easily and even extend throughout the entire tooth. Weak or eroded enamel can be a result of genetic factors as well as grinding, diet and certain health conditions such as acid reflux.2
  • Hard foods: Hard candies, stale bread, ice cubes, and un-popped popcorn kernels are all frequent perpetrators of cracked teeth. It’s not difficult to mindlessly bite into a piece of food at just the right angle to create a fracture. To avoid this mishap, make sure to chew slowly and navigate pitted fruits and similar food items with care.
  • Accidental blows to the mouth: A direct hit to the mouth can cause chipped teeth, fractures, and other serious oral injuries. Most often these are the result of a sports incident, unexpected fall, or an auto accident. These types of tooth fractures may involve other complications: A blow to the mouth that causes a cracked, loosened, or knocked-out tooth should be considered a dental emergency that requires prompt attention.
  • Extreme temperature changes: When tooth enamel is rapidly exposed to opposite temperature extremes – for example, immediately biting into an ice cube after burning your mouth on a piping-hot cup of tea – it can lead to hairline cracks. This is because enamel expands and contracts during temperature changes. If it does so too quickly, fractures are likely to form, or existing cracks may worsen.
  • Age: With a lifetime of use comes weaker enamel and teeth that are generally more susceptible to injury.3 This is why older individuals tend to experience cracked teeth more frequently. To prevent cracks, worn-down enamel should be properly repaired or restored according to your dentist’s recommendation.


A cracked tooth is something dentists encounter regularly. If diagnosed early, then the problem can usually be solved with a straightforward dental or endodontic procedure. To prevent cracked teeth, be cautious when eating hard foods and chew slowly. If you grind your teeth, ask your dentist about a nighttime mouth guard for protection. If you play contact sports, wear a mouthguard. Take care of your enamel by avoiding sugary soft drinks and highly acidic foods and beverages – the stronger your enamel, the less prone your teeth will be to fractures. Get regular dental check-ups to make sure any potential problems are caught early on.

If you are experiencing pain on biting or chewing or increased sensitivity to temperature, you may have a cracked tooth. Do not ignore it. Make an appointment with your dentist to have the tooth evaluated and avoid further complications.4


Additional resources

Looking for more information? Brush up on dental care basics.

Have a cracked tooth? Protect Your Smile. Find a dentist.




1Cracked Teeth. Retrieved from

2Stein, M. (28 April, 2016). Causes of Brittle and Fragile Teeth: Why Do My Teeth Keep Breaking? Retrieved from

3Friedman, M. (2018, January 17). Teeth and Aging: How Your Mouth Changes As You Get Older. Retrieved from

4Do you have a cracked tooth? (2003). The Journal of the American Dental Association, 134(4), 531. doi: 10.14219/jada.archive.2003.0205