When a crack extends from the occlusal (chewing) surface towards the root, we call it a cracked tooth. These cracks may be very small or very large. The crack often causes damage to the pulp of the tooth. Primary symptom of a cracked tooth is pain upon chewing. This pain may be irregular and sporadic.
The depth and position of the crack determines whether the tooth is restorable. If the crack is in the coronal portion of the tooth, then placing a crown with prevent futher flexing of the tooth as well as prevent bacterial leakage through the crack.
A crack extending down the root surface is also commonly referred to a root fracture. Root fractures can be difficult to diagnose. Often they are associated with a deep, narrow, periodontal defect. However, a draining abscess can also cause a deep narrow pocket, which can easily be confused with a root fracture.
In the picture above, the extracted tooth has been dyed. The periodontal ligament picks up the stain. You can see that in the area of the crack, the pdl has broken down and a deep, narrow periodontal defect has developed on the line of the crack.
A cracked tooth that is not treated will worsen and lead to loss of the tooth. Early diagnosis and treatment are essential in preserving these teeth.