What It Means To Have CTS




           Cracked tooth syndrome (CTS) is a condition in which your tooth has a craze line (crack) in it that is causing you discomfort on closing together, biting, chewing or even sometimes spontaneously. The pain may occur every time you chew on something or only intermittently. It may occur when you bite together, when you open from biting or both. A crack in your tooth may also result in sensitivity to cold temperatures, sweets and less commonly heat. This happens when hot, cold or sugary fluids pass through the crack in your tooth to its sensitive, inner layers. This process predisposes your cracked tooth to decay, abscess and fracture. In fact, along with excessive direct restoration (filling) size, cracks in your teeth are the most reliable indicator of increased fracture risk. The presence of both is almost a sure predictor that the involved teeth will break at some time in the future. These craze lines in your teeth are rarely visible to the naked eye and may only be seen under certain forms of illumination or under extreme magnification. It is now the case in industrialized nations like ours that cracks in teeth are becoming the primary cause for needing root canal treatment and nearly so for tooth loss.1


The ultimate consequence of "Cracked Tooth Syndrome", a fracture into the pulp.

           The source of your discomfort comes from the surfaces on either side of the crack rubbing upon each other as the tooth flexes (minutely) under function. You will only have discomfort if the crack has extended through your tooth's outer layer of enamel into its next layer called dentin. Dentin has nerve endings in it that spread from your tooth's pulp (nerve chamber) so friction along craze lines within dentin will be uncomfortable. If the crack reaches into your tooth's pulp, the discomfort may be constant and worsen on chewing or closing. If your tooth's pulp is breached in this manner, it can abscess in time. If the crack in your tooth has lengthened too far down its root, or between them in the case of a multi-rooted tooth, it will need to be extracted. Craze lines that penetrate your tooth's nerve chamber, but do not make it unsalvageable, will necessitate endodontic treatment (root canal therapy) if your tooth is to be saved. If the crack in your tooth has entered its dentin, but not its pulp, reinforcing it with a bonded core before crowning (capping) it will usually solve the problem as the crack will generally be eliminated when your tooth is prepared to accept the core and crown. It is frequently possible to locate the position (but not the extent) of a craze line on your tooth with an instrument called a "tooth sleuth" that can guide the crown preparation process. Often it is difficult to determine whether the crack has reached your tooth's pulp or not. In these cases a provisional crown is placed on your tooth for 30 to 60 days after the bonded core has been placed during which time Dr McArdle may refer you to an endodontist (root canal specialist) to evaluate your tooth's response to this procedure. If at the end of this time your tooth has been comfortable and no nerve damage has been found on endodontic evaluation, the definitive crown can be put in place. If your symptoms are unchanged or actually worsen during the 30 to 60 day period, your tooth will need further treatment by the endodontist.

           Your teeth can be cracked in many ways. Chewing on something hard, such as a foreign object in your food, can cause crazing. Trauma from an automobile accident or a sports injury can cause cracks in your teeth. Large fillings can also produce craze lines. If you grind your teeth severely while sleeping (a condition known as bruxism), cracks in your teeth may result. Chewing ice is a major cause of crazing. The combination of hardness and extreme temperature change, the latter causing volume shifts in your tooth like a frozen milk bottle bursting, is a sure way to damage your teeth. Never chew ice! Root canalled posterior teeth that are not protected with posts and crowns crack easily because the one disadvantage of endodontic treatment is that it hollows your teeth out, making them brittle. Always crown your root canalled back teeth!




     The Journal of the American Dental Association
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  Risk Indicators for Posterior Tooth Fracture
  James D. Bader[1], Daniel A. Shugars[2], Jean A. Martin[3]
  JADA 2004; 135:883-892.


Background. Identifying posterior teeth that are at heightened risk of developing cusp fracture is an inexact science. Risk indicators based on controlled observations are not available, and dentists' assessments vary.

Methods. The authors conducted a case-control study of cusp fracture in restored posterior teeth. They evaluated 39 potential risk indicators identified in previous uncontrolled studies for an association with fracture in 200 patients with fractures and 252 patients without fractures. These risk indicators delineated patients' clinical characteristics and behaviors, as well as clinical characteristics of individual teeth. The authors used logistic regression to develop models identifying risk indicators associated with fracture, both between case and control subjects and between case and comparison teeth in case subjects.

Results. Two risk indicators appeared in both models. The presence of a fracture line and an increase in the proportion of the volume of the natural tooth crown occupied by the restoration substantially increased the odds of fracture (P < .001). Additional risk indicators were unique to the case subject–control subject model, including subject age and other measures related to the relative size of the restoration or to loss of dentinal support. Neither patient behaviors such as clenching, grinding and biting hard objects nor occlusal characteristics such as guidance, cusp anatomy and general wear patterns were strong predictors of fracture risk.

Conclusions. Among posterior teeth with restorations, two clinical features were strongly associated with the risk of cusp fracture: presence of a fracture line in the enamel and proportional volume of the restoration.

Clinical Implications. Dentists assessing the risk of fracture should consider a detectable fracture line or a high ratio of restoration-to-total-crown volume as important indicators of elevated fracture risk.


1 Clark DJ. The epedemic of cracked and fracturing teeth. Dent Today. 2007 May;26(5):90-5.

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