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Cracked Teeth

An overview of Cracked Teeth

Cracked lower molar tooth with decay and fractures extending from silver filling.

Figure 1a: A tooth with obvious fractures that did not have symptoms. Some of the fractures in this tooth had been present long enough to develop dark pigment in the fracture lines. The one at the bottom of the photograph is newer and lacks pigment. The tooth developed decay either before or after the newer crack occurred and required treatment to save it.

Cracks in teeth range from the obvious, visible fractures (Figure 1a) to less obvious (frequently invisible) microscopic fractures. Frequently, those that are difficult or impossible to see are more serious. Cracks can occur in the crown of the tooth (the part you can see protruding through the gums), or in the tooth’s root, where they can be difficult to diagnose and are generally more serious. Some cracks are easily repaired with bonded fillings, while some are too extensive to be fixed at all.

A bonded filling can sometimes buy enough time for the patient to plan for the expense of a crown. At the time of the photograph, the tooth in Figure 1b had been successfully restored with a filling for a few years. However, it can be difficult or impossible to achieve ideal tooth contours with such large fillings, increasing the likelihood of an overhanging dental restoration, food compaction injuries and other potential problems.

A fractured lower molar tooth with caries restored with white composite resin filling.

Figure 1b: Although the tooth appeared badly cracked, a bonded filling was able to repair the decay and stabilize the fracture long enough for the patient and dentist to consider the best long term option for restoring the tooth’s contours and protecting it against propagation of the crack. These would typically include an onlay or crown.

Considering the risk of a fracture spreading through the tooth, the most reliable protection is generally achieved with a full coverage restoration like a crown or onlay. Both of these restorations are made outside the mouth, where it’s usually easier to achieve ideal contours that will blend smoothly with the tooth. Moreover, without the protection of a full coverage restoration, the patient may be at increased risk of losing the tooth if the crack should spread deeper into the tooth.

Only a dentist is qualified to diagnose and appropriately treat the tooth, taking into account the extent of the crack as well as the patient’s symptoms, history, habits, personal needs, presence (or absence) of an opposing tooth, bite relationship between the teeth; and other factors.

How does the dentist diagnose Cracked Teeth?

Note: ToothIQ.com contains general information. Only a dentist can properly diagnose your specific condition.

Diagnosing cracked teeth starts by determining the severity of a crack. This can be done by answering the following questions.

  • Does the tooth hurt (especially to bite and cold)? If so, the crack is likely to be at least as deep as the dentin layer of the tooth. If not, it is likely more superficial, or has been present long enough for the tooth to produce “reparative dentin” over the crack. Reparative dentin is a calcified material produced by living cells called odontoblasts in the pulp space of a healthy tooth. It is produced at an accelerated rate when a tooth sustains an injury, and can often be seen on X-ray images. If the tooth is asymptomatic, you may have time to consider your options for fixing it, and conservative options may work – at least in the short term. However, even if a cracked tooth does not hurt and can be repaired conservatively in the short term, the most reliable protection against growth of the fracture and subsequent infection / tooth loss is generally provided with full coverage restorations (i.e. onlays and crowns).
  • Is the tooth loose? If so, it may be fractured at or just beneath the gum level, and the fracture is likely deep into the tooth. These are normally serious problems.
  • Is the tooth in pieces? If so, are the pieces loose? Often vertical or oblique fractures will result in one side being loose and the other stable. These are also serious problems.
  • Is there stain or pigment in the crack? If so, the crack has likely been present for awhile. If it is, and the tooth has never been symptomatic, the crack may be relatively superficial. Sometimes these superficial cracks are called “craze lines.” This doesn’t necessarily mean the cracked tooth shouldn’t be fixed, but the urgency for fixing it may not be as great, and conservative treatment may be an option. Again, a full coverage restoration like a crown or onlay is generally the most reliable way to prevent progression of a crack in a tooth. If a fracture deepens, it usually does so along a craze line. Craze lines in the back teeth are often of greater concern than those in the front teeth (from a structural point of view), because the back teeth typically experience greater chewing forces. It’s common to see elderly patients with craze lines in the front teeth that have visibly stained brown over time and yet, never fracture.
  • Has the tooth had root canal (endodontic) treatment? If so, it is more likely to fracture than a tooth that has not had a root canal. This does not mean that every tooth that has been endodontically treated needs to be crowned. In general, the risk of an uncrowned tooth breaking after root canal therapy increase the further back the tooth is in the mouth (where greater chewing forces are exerted), and the more the tooth has been decayed or filled.

How are Cracked Teeth treated?

If a tooth is diagnosed with a crack, there can be several options for treating it. Less severe (superficial) fractures that require treatment can sometimes be treated conservatively with a bonded filling. It’s important to understand whether or not such a restoration is expected to provide a long term solution or not. Usually, the most reliable way to prevent a fracture from spreading through a tooth and causing future problems is to cover it with a crown or onlay.

Studies have shown that about 20% of teeth with cracked tooth syndrome require root canal treatment. Adjusting the bite on the tooth (occlusal adjustment, single tooth) will generally not resolve the symptoms of a cracked tooth for long. If the fracture runs into the roots, the tooth may have to be removed. Often, fractured teeth that need to be removed are excellent candidates for replacement with a dental implant. As part of the diagnostic process, the dentist will generally expose at least one X-ray image (radiograph), and may take photographs to better communicate the findings with you.

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Author: Thomas J. Greany, D.D.S. / Editor: Ken Lambrecht

This page was last updated on March 2, 2018.

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