One of the reasons some people fear root canal is that they do not understand the process. What is mysterious or unknown to us tends to heighten our anxiety and fear. Once the mystery is revealed, the associated fear will often resolve as well. To understand root canal therapy, we need to have a basic understanding of the tooth’s anatomy. A tooth is hollow, like our bones, and is composed of several layers. The outermost layer (above the gum-line) is called the enamel. Beneath the gum-line, a substance called cementum covers the tooth roots. Under the enamel and cementum is the dentin. Beneath the dentin is the dental pulp. The pulp is composed of tiny blood vessels, connective tissue, nerve fibers, and other cells.
Root canal therapy is a complex procedure that requires both skill and experience. To begin the procedure, the dentist numbs the area of the infected tooth with local anesthesia. In most cases, a clamp is placed over the tooth, and a rubber membrane (rubber dam) is spread over the clamp to isolate the tooth for the procedure. A small hole is made through the enamel and dentin, and into the pulp. The pulp is then removed with small stainless steel files of increasing diameter. After the pulp has been removed, the inside walls of the root(s) are shaped, almost like a sculpture. Nickel-titanium files that fit on a slow speed drill can aid this process. During the procedure, solutions containing sodium hypochloride (bleach) and ethylenediamine-tetraacetate (EDTA) are used to both kill the remaining pulp tissue and the bacteria within the tooth’s root(s), and also remove the debris produced by the files.
After the pulp is removed and the inside of the root(s) shaped, the canal is dried with paper cones. The canal(s) are then filled with gutta-percha. Gutta-percha is a purified form of Mazer Wood Trees that is combined with zinc oxide and other materials to form the rubbery filling that is placed inside the tooth’s root(s). The gutta-percha is then cemented into the root(s) with a sealer that usually contains zinc oxide and eugenol. The goal of the filling procedure is to hermetically seal off the tooth against bacteria, preventing re-infection of the tooth.
There are two main techniques for filling a root canal, lateral and warm vertical condensation. Although research is scanty, warm vertical condensation appears to have the advantage of more completely filling the tooth’s root(s), especially the accessory nerve canals.