• Teeth can develop fractures for a number of reasons. From repetitive chewing on your teeth, day after day, teeth may develop cracks. Each time you chew on your teeth they flex slightly from the chewing force. This flexing over time can cause teeth to develop fine cracks (stress fractures).
• A history of clenching or grinding (bruxing) teeth can result in cracks.
• Chewing on hard substances or foods such as ice, popcorn kernels or candy.
• Trauma to the mouth such as a blow below the chin or lower jaw.
• Large fillings and especially amalgam fillings,that are deep or that involve the contacts between teeth (inter proximal contacts), can weaken the teeth resulting in tooth fracture.
• It has be suggested that bone loss associated with periodontal disease can predispose a tooth to root fracture because of decreased support.

This fracture extends from the back of the tooth over the tongue (lingual) side.

What are the Signs and Symptoms of a Cracked Tooth?

• The patient has a hard time describing the problem.
• A history of erratic pain upon chewing (shock or jolt), especially upon release of biting pressure (disclusion).
• Discomfort with extreme temperatures, especially cold.
• Perhaps there is a history of the dentist relieving the bite by grinding on the tooth because of off and on pain.
• Dental X-rays tend not to show anything wrong with the tooth
• Some patients complain of a soreness while chewing.
• If the crack involves the root there may be a localized periodontal pocket or defect.
• If the cracked extends to the nerve, there may be signs of irreversible inflammation (irreversible pulpitis) which will lead to pulpal death and ultimately an abscessed tooth.
• Sweet sensitivity with a lack of detectable decay clinically or on an x-ray.
• Often patients will give a history of other cracked teeth.

NOTE: Depending on the size and location and direction of the crack the patient may experience any combination of these symptoms or perhaps others, making the diagnosis a frustratingly difficult one!

Why do Cracked Teeth Hurt to Chew on?

Biting down on a tooth physically loads the tooth, stressing it, thus distorting its shape. This distortion disrupts the fluid within the crack. Upon release of biting pressure (disclusion) the fluid within the crack is driven towards the nerve chamber (pulp) eliciting pain. This phenomenon is unique to a crack and is a useful aid in diagnosis of the offending tooth.

Why Don't Cracks Show Up on a Dental X-Ray?

Rarely will a crack in a tooth show up in an X-ray. This is because the X-ray beam must be parallel to the crack in order to penetrate it. In some cases however other radiographic signs of a crack can be found besides actually seeing the crack itself. In some cases of a vertical root fracture, if the crack has been present long enough, vertical bone loss paralleling the root can be seen.

Dark area around mesial (front) root on this root canal treated tooth is in a J shape.

This is typical of a vertical crack that extends to the root surface.

What's the big deal, so what if my Tooth is Cracked?

Left untreated cracked teeth can result in pulpal necrosis (death of the nerve), and abscess (infection) requiring root canal treatment or extraction. In severe cases the tooth can actually split in two resulting in an non fixable tooth requiring removal.

The sections of a split tooth (in halves) are easily separated.

Crack can be visualized across the floor sometimes after removing the filling from a tooth.

How are Cracked Teeth Fixed and Why?

The good news is that most cracked teeth can be retained long term, it should be noted however that a cracked tooth is a compromised tooth even with the proper treatment.

The key factor is to find the crack early on in its development.

If caught early enough, with the proper treatment, cracks can be halted or at least slowed down allowing the tooth to retained long term. If allowed to progress untreated, a cracked tooth depending on the direction of the crack, may become hopeless requiring removal.

The treatment of a cracked tooth involves removing the affected cusp and placing a crown (cap) on the tooth to hold the tooth together preventing the crack from progressing. In cases where the crack involves the nerve chamber or has caused irreversible inflammation of the nerve, root canal treatment will be necessary prior to crown placement.

What can I do to Prevent Cracked Teeth?

• If you are a clencher or bruxer (grinder) of your teeth particularly at night time, then have a night guard (bruxing appliance made) to protect your teeth.
• Do not chew on hard objects such as ice, hard candy (jaw breakers etc.) or pop corn kernels.
• Wear protective mouth guards when participating in contact sports to protect your teeth.

It should be noted that even with these precautions teeth may develop stress fractures just from every day use over time.