Causes

There are a number of reasons why teeth crack and they are compounded into:

• Anatomical risk factors: anatomical or structural features of your teeth that make them more prone to crack.
• External risk factors: given that we normally eat a combination of cold and hot foods, sometimes in the seam meal, the temperature variation produces expansion and contraction of the tooth structures, more specifically, the enamel. These variations, added to the multiple low-frequency loads produced by chewing, contribute to the appearance and propagation of one or multiple cracks.

On the other hand, existing old and badly adapted restorations such as big amalgams or posts, weaken the tooth structure. Furthermore, occlusal factors can also be associated with the presence of deep cracks. This is usually seen in isolated back teeth, as a result of multiple previous extractions without the replacement of the missing teeth.

Other causes can include

• Dental trauma associated with biting onto hard objects or foods.
• Parafunctional habits such as opening objects with your teeth, chewing ice, bones, nuts or seeds.
• Bruxism: grinding or clenching your teeth.

Signs and symptoms

Commonly, a cracked tooth can produce hypersensitivity to cold and pressure.

• Mild to severe pain or discomfort to cold that takes longer to pass after removing the stimuli.
• Tenderness on biting specific types of food that gets worse when the pressure is released.

This makes the diagnosis harder, as it usually can be confused with dentin sensitivity. However, the main feature of this syndrome is the clinical and radiographic absence of swelling.

Diagnosis

The diagnosis of a cracked tooth is merely based on the history of the pain. When did you start feeling it? what triggers the pain? what makes it stop? Are some of the questions that your dentist will be asking you during the examination. The thing with these incomplete cracks is, they usually do not appear as obvious on the X Rays nor clinically. Therefore, it is vital that the patient gives a very detailed description of the symptoms, so that the dentist can make the diagnosis as accurate as possible.

The dentist will also perform a couple of tests during your visit. For example, tapping on some of your teeth, or having you biting onto a special instrument to determine where the pain is coming from. However, this step can be particularly difficult in the lower teeth, as they are all connected by the main nerve that goes along from your ear to your chin. Hence, sometimes the pain felt in one tooth can refer to the ones next to it, making the diagnosis even more challenging.

Once the crack has been identified, the next step is defining the prognosis of the tooth. The prognosis refers to the possibilities of saving the affected tooth, and it will depend on the location and extent of the crack, as well as its direction (vertical, horizontal or oblique) and what tissues are involved. Basically, the deeper the crack is, and the more tissues involved, the worse is the prognosis. This will be key in determining the treatment.

The importance of early diagnosis has been widely associated with the best restorative prognosis. This means the sooner you visit your dentist when the symptoms appear, you will have more chances of needing more conservative treatments.

Treatment

The more rapidly a cracked tooth is treated, the less irreversible damage it will get. This is due to the possibility of assessing the extent of the crack before it spreads further and affects dental tissues or potentially reaches the nerve.

That said, the treatment of a cracked tooth will depend on the extent of the crack. The procedures can be as conservative as grinding the tooth out of occlusion (aiming to decrease the forces acting on it), to the elaboration of a composite filling or a restoration made in a dental lab, such as a crown or a cap. Likewise, if the crack affects the nerve, there are high chances the tooth needs root canal therapy If the crack extends beyond the nerve and reaches the root, the tooth might need to be extracted.

It is also important to bear in mind what caused the tooth to crack, whether it was a result of you grinding your teeth, biting something hard, or an existing restoration failing. Addressing the root of the problem will lead your dentist to come up with the best treatment plan. This is key, especially for patients with bruxism, or with multiple missing teeth. In their case, treating one tooth could not be the definitive solution, and full mouth rehabilitation might be needed.

References

• Longridge, N., Youngson, C. (2019). Dental pain: dentine sensitivity, hypersensitivity and cracked tooth syndrome. Prim Dent J. 8 (1):44-51.
• Banjeri, S. Mehta, S.B., Millar, B. J. (2010). Cracked tooth syndrome Part 1: aetiology and diagnosis. Br Dent J. 2010 208 (10):459-463. Doi: 10.1038/sj.bdj.2010.449
• Banjeri, S. Mehta, S.B., Millar, B. J. (2010). Cracked tooth syndrome Part 2: restorative options for the management of cracked tooth syndrome. Br Dent J. 2010 208 (11):503-514. Doi: 10.1038/sj.bdj.2010.496