Every tooth develops with a pulp within it. The pulp is a very complex structure consisting of a nerve, blood supply, lymphatic system and embryonic cells which help protect the tooth from insult over the course of time. Depending on which tooth is involved there could be one, two, three, four or rarely five separate canals within the tooth, each filled with a dental pulp.
The pulp is very easily damaged and unfortunately has a relatively low potential to repair itself once damaged. Excessive decay, fractures and trauma all have the ability to expose the pulp allowing bacteria to enter. Once the bacteria enter the pulp an irreversible irritation followed by infection of the pulp takes place. Subsequently the abscess that develops can cause pain, swelling, inability to comfortably chew your food and depending on the location, a possible life threatening infection. Once the pulp is sufficiently irritated or infected a root canal must be performed.
Root canal therapy involves removal of the pulp, bacteria and all associated bacterial byproducts. The remaining debrided canals are then filled with a biologically compatible material that seals the canals. In many cases, since the infected pulp is removed in total with all its components, many teeth have to be reinforced with a crown following root canal therapy.