Cracked tooth syndrome (CTS) is where a tooth has incompletely cracked but no part of the tooth has yet broken off. Sometimes it is described as a greenstick fracture. The symptoms are very variable, making it a notoriously difficult condition to diagnose Causes of a cracked tooth Teeth crack because of a variety of issues, including: pressure from teeth grinding. fillings so large they weaken the integrity of the tooth. chewing or biting hard foods, such as ice, nuts, or hard candy.