What is a root canal and why would anyone want one??
The term “root canal” conjures terrible images in most people’s minds. You keep hearing the horror stories about how much they hurt, or that they didn’t work, or that they are expensive. Well, think again! Yes, a few ARE painful and difficult, but for the most part they are the exception rather than the rule. A vast majority go from beginning to end with either no pain (sometimes no shot is needed), or with minimal pain, mostly felt after the patient leaves the office and the anesthesia has worn off.
The picture above shows an actual tooth that has been sectioned in order to show the entire length of the nerve (called the dental pulp) in a fairly straight upper first premolar. You can see that the nerve in the living state is nothing more than a piece of meat inside the tooth. Nature put it there during the process of forming the tooth while it was first developing, beginning just a bit after birth. It’s purpose was to lay down the hard structure of the tooth.
The tooth shown above is from a young individual. We can tell this because the pulp inside the tooth is fairly large. In fact, the pulp continues to lay down hard tooth structure throughout a person’s life, depositing it inside the tooth and making the space it occupies within the tooth root (called the root canal) smaller and smaller as you get older and older. The dental pulp itself actually contains a number of structures including nerves, blood vessels and connective tissue. When it is healthy and functioning properly, it keeps the tooth structure hydrated and resilient so that the tooth can withstand shocks without breaking.
Left alone, the pulp in a tooth has no reason to get sick. However, it is only a piece of tissue like any other soft tissue in your body. Take your finger, for example. When you injure your finger, say you cut it badly, or get an infection under a fingernail, it reacts immediately with pain, and shortly thereafter, it swells up, getting red and warm. These are the signs of inflammation, and the dental pulp reacts the same way when it becomes injured.
Injuries to the dental pulp tend to be from decay which becomes so deep in the tooth structure that it actually touches the nerve. Inflammation of the nerve can also be caused by trauma (say a hockey puck to the mouth), and frequently is the result of multiple assaults by dentists trying to eliminate yet another area of decay.
Lets say that you have a cavity and the decay touches the pulp. Where it touches the pulp, it is likely to swell up a bit. But consider that the pulp, unlike your finger, is contained tightly inside of the tooth. Any swelling in the nerve is likely to cause such tightness inside the pulp chamber that the blood vessels that supply the pulp with oxygen and food are shut down. This is a condition known as ischemia, and is the same thing that happens when you wind elastic bands around a finger for too long. It is a VERY painful condition. The nerves that travel with those blood vessels are connected with your brain by means of very long cellular fingers called axons. Your brain gets the message and you have a bad toothache. Even worse, the condition is not reversible, and the ischemia causes further shutting down of the blood supply until the entire dental pulp dies off.
You might think that once the pulp died off, the nerve fibers would die off with it and the pain would cease. Sometimes, this actually does happen, but many times, the nerve fibers remain alive because the main cell bodies of the nerves themselves live outside of the teeth (in clumps of nerve cell bodies called ganglia—-the major ones are located about an inch and a half inside your head about even with the earlobe). This leads to chronic pain, especially with cold or hot foods because the bare nerve fibers are sick, but alive encased in a hard tomb with a bunch of very smelly and infected dead stuff. Abscesses can be seen on x-rays if the tooth has been infected for more than a few days:
Even if the nerve fibers inside the tooth die off, and the immediate pain does end, you are still not out of the woods. That dead material begins to leak out of the tip of the root and a pus sac forms (see x-ray on left) filling up with pressurized pus which causes extreme pain when you touch the tooth. This is the beginning of an abscess. The picture above shows a young boy with a severe abscess.
Left alone, abscesses can become quite serious. In the days before antibiotics and modern surgery, dental abscess was a common cause of death. Upon occasion, especially in the case of an untreated abscess of an upper front tooth, the patient can get a brain abscess which can kill him. This brain infection is called cavernous sinus thrombosis. Click the image above to see my page explaining the mechanics of cavernous sinus thrombosis and its relationship to the “dangerous triangle“.
Another killer is Ludwig’s angina(See image above). This infection is caused by an abscess of a lower tooth. The major symptom is severe swelling under the tongue, chin and neck. The swelling may become so severe that the patient can no longer breathe. Before the advent of modern dentistry, this infection was one of the most frequent causes of death, particularly among the wealthy upper classes who had access to large amounts of sugar.
For a large part of human history, the only treatment for these death dealing infections was extraction of the offending tooth. Usually done with an instrument known as a pelican (see image below), and without anesthesia except for a glass or two of whiskey (if the patient could afford it), the tooth was RIPPED out as quickly as possible, most frequently breaking the tooth. Even if the tooth broke leaving the roots still in place, the procedure could save the patient’s life by effecting drainage of the pus and relief of the pressure of the abscess.
Even today, extraction of the offending tooth is still a viable alternative for relief of a toothache. It is usually less expensive to remove a tooth than it is to do the root canal, however, many of the most damaged teeth must be extracted surgically which increases the cost of even this relatively less expensive alternative.
But today, you can also opt to keep your teeth, even if they are painful or abscessed. You would do this to avoid the trauma of an extraction, and to retain your natural tooth. They don’t grow back once pulled out! Properly treated, an endodontically treated tooth remains a useful tooth with no continuing pain or abscess.