Understanding the Root Canal

This article is a guest piece written by Dr. Mark Burhenne, the Virtual Dentist.

No one will ever forget Dustin Hoffman having his front teeth drilled through to the nerve by a Nazi dentist in the film Marathon Man. Always a favorite topic with comedians and Hollywood film makers, the root canal, poorly understood and unjustly accused, lives on in disrepute.

Johnny Carson maligned root canals so much on his Tonight Show that a while back a New York dentist in fact brought a suit against him. And we all know Bill Murray was acting when he begged Steve Martin (the dentist) for a root canal in the film Little Shop of Horrors.

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So then, we all know what a root canal is. Don't we? We know it's amusing when it's happening to someone else. We know it's pretty absurd when someone pleads for a root canal. We know it's going to hurt a lot! But in fact, few of us really know what a root canal is and how beneficial it can be to the failing dentition.

Although you may find it difficult to believe this, the root canal has long been a measure for advanced civilization. Ancient civilizations developed this highly refined method of saving teeth that otherwise would have been lost. Available usually to the upper classes such as the nobility and wealthy, root canals were performed on pharaohs, kings, queens and dignitaries alike. Teeth from the peasants were often extracted and sold for transplantation to aristocrats.

It was once thought that an "elusive" worm was responsible for causing tooth decay. Many therapies were developed to kill this worm including, in 1728, the rinsing of one's mouth using one's own urine morning and night. Fortunately, for us, this remedy was not effective, and was eventually replaced by other more "tasteful" remedies. In time, it was understood that the clean and complete removal of the nerve was the best way of eliminating the toothache caused by extensive decay.

To fully appreciate the root canal (and there are those of us that actually do!), one must have a better understanding of tooth structure. A tooth is born from an embryonic tissue "bud". This tissue then lays down around itself the calcified tissues of the teeth, dentin and enamel. Once the tooth is formed, the inside tissue, consisting of blood vessels, nerves, and specialized cells (still capaple of forming dentin), lives on.

This pulp tissue is fed by blood vessels that enter the tooth from the very tip of the root and travel up the root canal into a chamber in the middle of the tooth. If the tooth has three roots, as do upper molars, the three root canals converge at this central chamber.

As tooth decay approaches this chamber, the pulp tissue becomes irritated by the acids released by the bacteria which cause the decay. The pulp tissue becomes inflamed and begins to constrict the blood flow to this pulp tissue. Usually by this time there is a toothache present. If unheeded, the pulp eventually becomes irreversibly inflamed and dies.

As a result, toxins are released from the dead tissue out the end of the root tip and into the surrounding jaw bone. This can infect the jaw bone and lead to the breakdown of the tooth's supportive tissues. It can even lead to death.

The prompt removal of this pulp tissue at this "point of no return" is then required to save the tooth and the surrounding bone. By removing the source of the the toxins, the tooth can maintain itself for the life of the patient. Once the pulp tissue is removed, files are used to clean and shape the inside of the canal, making sure all bacteria and toxins are removed. Confirmation of the file reaching the very tip of the root can only be accomplished via a series of x-rays showing the actual location of the file in respect to the root canal and root tip.

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Once the length has been established, the canal is shaped to facilitate its filling. Then dried, the canal is filled successively with rubber cones and a paste. This allows for the canal to be completely filled to prevent further chance of infection. Later, a crown is placed over the tooth, to help maintain its strength over the years (a non-living tooth is slightly more brittle).

Why does the thought of a root canal send grown men into the arms of their mothers (or in Bill Murray's case, to his local dentist). Why all the fuss over a procedure that enables your dentist to save an infected and aching tooth, rather than extracting it and placing a bridge or denture in its place? Is it the fear of the unknown? Is Hollywood to blame? Hopefully you will never have to answer this question for yourself. See your dentist every six months, and be virtually assured you won't have to.