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The Split Tooth - A Cracked Tooth Gone Bad

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drsantoshpatil's picture
Joined: 10 Jul 2009

Talking about cracked teeth is sometimes confusing. There are several types of cracked teeth. The treatment and prognosis of a cracked tooth depends on the type, location & severity of the crack.

Types of cracked teeth include: craze lines, fractured cusps, cracked tooth (restorable type and non-restorable type), split tooth & vertical root fracture.

A split tooth is caused by a cracked tooth that has gone untreated over a period of time. The tooth is literally split into two pieces by a crack that runs through the tooth. A tooth can be split mesio-distally or linguo-buccally. The crack of a split tooth includes damage to the root itself. The crack of a split tooth can be seen crossing the floor of the pulpal chamber. This is a sure sign of a non-restorable tooth.

Diagnosing Root Fractures

Diagnosis of a vertical root fracture is very difficult. It sometimes frustrates me to see how quickly some people diagnose a root fracture. I tell my patients that I like to rule everything else out before I make that assumption. I say assumption, because unless you can visualize the root fracture, you are making an assumption.

There are some clinical signs that can be associated with a vertical root fracture, however, they are not 100% diagnostic of a vertical root fracture.

For example, a long narrow periodontal pocket is often associated with a vertical root fracture. The periodontal attachment breaks down along the fracture line, creating this defect. However this same type of narrow periodontal defect can also be caused by an abscess draining through the periodontal ligament.
A j-shaped lesion is often associated with vertical root fractures. However, not all j-shaped lesions are fractured roots.
If visualization of a vertical root fracture is the most accurate way to diagnose a root fracture, how is that to be done?
Visualization of a fracture is best done using a microscope. A microscope with a light source will allow you to see fractures during endodontic treatment.

A microscope will allow you to determine if a crack goes down past the CEJ and into the root
or if it crosses the pulpal floor.

Visualizing a crack running across the pulpal floor of the tooth is is a 100% accurate diagnosis.

In these type of cases the tooth must be extracted

Cracked Tooth

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.

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.


Transillumination can be a useful diagnostic tool for identifying cracked teeth. As the light passes through the enamel, a crack will diffract the light and make the crack visible.

This may be an important tool to help you identify a cracked tooth. Accurate pulpal and periapical diagnostics are most important to determine if endodontic therapy is needed before a crown is placed.
Transillumination helps the patient to see the stresses that the tooth is under and realize the importance of coronal coverage.

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bijounmepani's picture
Joined: 29 Jun 2009
Re: The Split Tooth - A Cracked Tooth Gone Bad

How far is the "bite-on-the-mirror-handle" technique effective in suspecting a tooth fracture ., , .,. could someone give more insight on it and other viable techniques (other than those already specified by dr santosh) to diagnose a tooth fracture in a standard indian practice .,. ,

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Drsumitra's picture
Joined: 6 Oct 2011
The Split Tooth - A Cracked Tooth Gone Bad

 There are various factors that could influence long-term prognosis in endodontics. It is our duty to provide appropriate postoperative care for patients. A recent study1 shows that success rates of modern endodontic treatments are as high as those of implant surgery in the long run, thanks to advanced technology and materials used in endodontics. The significant finding reported from comparing implant and endodontic cases was that implants required more postoperative treatments to maintain them.

     In spite of the high success rates in endodontics, some of the cases will fail over time, even if the root canal therapy is performed perfectly. Common causes of postoperative failures are coronal leakage, root fracture, root resorption, and endo-perio complications. There is one thing in common among those causes: abnormal occlusal forces on a tooth can be a cause of failure in endodontic treatment. Wilcox, et al2 showed that canal enlargement of 40% to 50% of the root width increased susceptibility to vertical fracture. It has also been shown that attempts at removal of separated files usually result in the removal of a large amount of root dentin, which ends up reducing the root strength by 30% to 40%, leading to possible fracture later on.3 Root fracture occurs, depending on the crown-root ratio and anatomical features of the tooth, and the amount of remaining root dentin. Patients’ habits of mastication such as clenching and grinding are also considered to relate to root fracture by abnormal occlusal forces. The more favorable the crown-root ratio, the better the tooth can withstand masticatory forces, and the better the prognosis. Teeth with short, slender, and/or tapering roots have a poorer prognosis than those with long and broad roots. Multirooted teeth usually resist traumatic forces better than single-rooted teeth. Flared molar roots give better support than fused, conical roots. Broad occlusal tables and large crowns can contribute to increased mobility. The support of the tooth is determined by the height of the alveolar crest and the length and shape of the root. Canines can withstand loss of support better than lateral incisors by virtue of their longer roots and root concavities. Maxillary first premolars show early mobility because of the tapered roots. Some patients have teeth with short roots and others have root resorption, both of which have often been seen as a result of orthodontic therapy. Such teeth are less resistant to excessive occlusal forces which play key roles in root resorption and root fracture. Accordingly, orthodontic therapy and bruxism contribute to those phenomena.
















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