What causes a tooth’s pulp to become diseased? Most commonly, it is a cracked tooth, loose filling, or large cavity, all of which invite bacteria into the tooth that infect or inflame the pulp. Symptoms include darkening of the tooth, swelling of the gums nearby, and toothache from chewing or consuming hot/cold foods/drinks.
Root canals are predictably successful. 97% of root canal patients still had their saved tooth 8 years later, a Delta Dental study of over 1.6 million patients found. The 3% failure rate was mainly due to tooth decay, to which any tooth is subject. A root canal procedure is not painful nowadays, despite its notoriety. Discomfort is comparable to that of a tooth filling. What is painful is the symptoms of the diseased tooth pulp. So a root canal is actually a cure for the pain of diseased pulp. Now, temporary sensitivity does follow a root canal, but Ibuprofen suffices.
A root canal costs $350-$550 for a front tooth and $500-$800 for a back tooth, if done by a general dentist, and up to 50% more, if done by a root canal specialist (endodontist). Following a root canal, the tooth fractures more easily, so to protect it an artificial tooth on top (crown) is recommended. This is a separate procedure, which adds $800 -$1200 to the cost. Dental insurance plans vary in their coverage of root canals. A good one would pay at least 60% of the cost, whereas a poor one would pay only for a tooth extraction.
For more, a detailed description of root canal therapy as is available.