Teeth are constantly subjected to powerful chewing forces that my result in small cracks or craze lines to form in the enamel. Often these craze lines are shallow and present no danger to the pulp space inside the tooth. Occasionally, craze lines may propagate to form distinct cracks within the enamel and/or dentin. These cracks may be asymptomatic, or result in pain when biting down or releasing on tough foods. Your general dentist may be able to place a filling or crown on the tooth to eliminate the symptoms and slow the progression of the crack. Sometimes however, the crack can initiate symptoms within the pulp tissue that eventually may require root canal therapy. Cracks may be present only in the superficial layers of the tooth, or may propagate down the root of the tooth or from one side to the other. Your endodontist is often able to see the extent of the crack once root canal therapy is initiated, and inform you of the prognosis of the tooth. Some cracks may be managed by placing the permanent crown on the tooth immediately after root canal therapy is completed. Other cracks can propagate and worsen with time regardless of the placement of the crown, and may result in a persistent infection that requires extraction.