Posterior teeth may develop cracks (fractures) after years of use, especially with a history of large fillings. Symptoms of cracked teeth include sensitivity to cold and pain to chewing that some patients describe as a shock or jolt when biting. If the nerve has not been damaged too badly then a cuspal coverage restoration (onlay or crown) is recommended. If the nerve has been damaged then root canal therapy is indicated prior to placement of the restoration. If the crack has progressed too far down on the root surface extraction may be recommended due to likely continued symptoms from the crack in the tooth. A surgical operating microscope can help your Endodontist evaluate the extent of cracks in teeth during root canal therapy to get the best possible outcomes.