Inside each tooth is a pulp chamber that contains the nerves and blood supply for the tooth. When the pulp becomes infected due to decay or injury to the tooth, the pulp must be removed from the center of the tooth and the canals of each root. Once the infected pulp is removed, the remaining chamber is filled with a rubber-based material to seal it off.
All teeth that have had root canal therapy must be protected with a tooth-like artificial covering known as a crown (see crown section.) This is because teeth that have had the pulp removed are more susceptible to fracture.
Root canal therapy is an excellent way to save a tooth that would otherwise die and need to be removed.
If a tooth is sick, there are no disadvantages to root canal therapy. On rare occasions, however, root canal therapy may need to be redone to ensure that all of the infection has been removed.
The only real alternative is to remove the sick tooth. However, this will require a dental implant or bridge to fill the empty space and prevent the shifting of surrounding teeth. These solutions will ultimately cost more than the root canal therapy, and they will never equal the quality of keeping your natural tooth.