FAQs About Root Canals and Tooth Pain

A root canal is a treatment to eliminate or prevent pain and infection of a tooth. The inside of the tooth is filled with a soft tissue called pulp that is kind of like skin. It is filled with blood vessels and nerves. It is extremely sensitive and is the source of the hot or cold sensitivity that teeth can have. For various reasons this tissue can become infected and die. Root canal therapy cleans the dead, rotting pulp out of the tooth and replaces it with a biologically inert filling. This allows the tooth to continue to be used pain and infection free for many more years.

Your acute pain may temporarily go away, but the infection won’t. It will eventually travel through the tooth’s roots into the surrounding tissues. If left untreated, it may result in an abscess or even a systemic infection. That’s why you need to take care of it now.

A root canal is treatment to debride (remove and clean) gangrenous (dead and rotting) pulp tissue or pulp tissue that will become gangrenous from the tooth and then fill the resulting empty space with a biologically inert filling to prevent reinfection. Root canal treatment is accomplished by drilling a hole in the top of the tooth to access the pulp tissue in the middle of the tooth. The pulp tissue is cleaned using tiny files. Then a filling material is pressed into place in the roots of the tooth. The root canal treatment does include filling the roots but not restoring the tooth itself to replace tooth structure lost due to cavities and due to the procedure itself. Therefore a final restoration (usually a build-up and a crown) is also required.

I am often asked this question by patients. Root canal therapy seems expensive (see question #4) and antibiotic treatment is relatively cheap. The problem is that once the pulp in the tooth dies, the tooth is filled with gangrene (i.e. dead, rotten, infected tissue). Antibiotics cannot reach areas of dead tissue because there are no longer living blood vessels to carry the antibiotic to the gangrenous tissue. Just like any other part of the body affected by gangrene the only acceptable treatment is debridement (cleansing and removal of dead tissue) and possibly administration of antibiotics at the time of the debridement. The process of debriding gangrenous pulp tissue is part of the root canal therapy. Treatment with antibiotics may provide temporary relief from the pain caused by bacteria spreading out of the tooth, but they cannot eliminate the bacteria in the tooth. It is like taking antibiotics for an infected splinter. The source of the infection is left behind and it will just come back. Eventually after several antibiotic treatments, resistant strains of bacteria are likely to develop. Elimination of the source (gangrenous pulp tissue) is the only treatment that can provide elimination of the infection. This can only be accomplished by root canal therapy or extraction.

Root canal therapy seems expensive. Current average pricing ranges from about $900-$1400 for the root canal therapy (depending on the difficulty of the tooth involved) and about $1200 for the build-up and crown that is necessary to protect the root canal treatment.  It does seem very expensive to spend $2500 to fix one tooth. However, other alternatives are usually more expensive. Extracting and replacing a tooth with an implant currently costs about $5500 at most practitioners. So fixing the tooth is usually cheaper. More importantly, if properly maintained (brushed and flossed), a good root canal will probably last the rest of your life and a good crown usually lasts at least 20 years. If you invest $3000 for 20 years of pain and infection free use of your tooth. That is only $200 per year. The average family spends about $1000 per year on cable TV. Most people spend more time each day eating, talking, and smiling than watching cable. So fixing a tooth for $3000 is actually a relatively cheap investment.

The root canal treatment includes filling the root but it does not include filling the hole drilled into the tooth to access the pulp tissue or replacing tooth structure destroyed by cavities.  Also root canal treatment requires drilling a hole through the top of the tooth and down the roots. This process weakens the tooth, especially back teeth. The tooth remains strong enough to last, if reinforced by a crown. Without a crown the tooth is very likely to either break or crack. If it breaks, it often cannot be fixed. If a crack occurs, it can allow bacteria to reenter the root canal space and cause a new infection. Studies show that a good root canal with a good crown succeeds about 90% of the time. This is an extremely high success rate for any medical procedure. However studies show the crown is actually more important than the root canal itself. A bad root canal with a good crown still succeeds about 60% of the time, but a good root canal with a bad crown only succeeds about 40% of the time. A back tooth that has a root canal very likely will not succeed without a crown. Finally, in limited cases (small decay or no decay) a front tooth may only need a filling after a root canal. However, it is uncommon for a tooth with small or no decay to need a root canal.

A toothache is caused by dead or dying dental pulp. The dental pulp is a soft tissue in the middle of the tooth (see question #1 for more on the pulp). When the pulp is irritated sufficiently it will die. It can be irritated by bacteria from a deep cavity or trauma from deep preparation (drilling) on the tooth for a crown or filling. The pulp is trapped in a hard, enclosed space. If irritated it tries to swell like any other part of the body when irritated, but in this enclosed space it cannot swell. So instead of increasing in size like normal swelling, it increases in pressure. This high pressure cuts off the blood supply and the tissue dies from lack of oxygen. As the tissue dies, it is very painful.  Usually there is extreme sensitivity to hot and cold. A root canal is often done during this dying period. It will have the greatest chance of success if done, while the tooth is still alive. After, a while the tooth will completely die. At this point the space filled with pulp become gangrene (dead tissue). This dead tissue is a perfect food for bacteria and the inside of the tooth becomes abscessed. During this time, the tooth usually feels better. Eventually the abscess leaks out of the tooth into the bone that holds the tooth. When the bone becomes abscessed it becomes extremely painful. Most patients describe it as the worst pain they have ever felt (even patients that have had traumatic accidents and given natural childbirth). When your dentist tells you that a tooth needs a root canal that may not even hurt, it is because he or she is trying to prevent you from getting to the point of having this terrible pain. The only treatment to eliminate the pain and infection of a dying or dead tooth, is removal of the dead or dying pulp. This can only be accomplished by root canal therapy or extraction. Antibiotics may provide temporary relief but cannot fix the problem (see question #3).

No. Sometimes when a tooth is prepared for a crown, the trauma of the crown preparation can cause the pulp of the tooth to die. Sometime after the crown is placed the tooth will develop a toothache and will need a root canal. However this is rare. Doing a root canal before every crown to prevent this situation would lead to many, many unnecessary root canals. Most of the time teeth with large but not deep decay can receive a crown without a root canal.

Usually not. Generally, a root canal procedure is no more painful than getting a filling In the past, when dentists actually used Novocaine, it was difficult to get infected teeth numb and keep them numb. During this time root canals got a bad name for hurting. With the advent of modern anesthetics, especially lidocaine and articaine, it is possible to get infected teeth numb and keep them numb long enough to finish a root canal. Usually patients feel no pain during a root canal and feel better immediately afterward. In rare cases, a patient will experience continued or increased toothache for 2-3 days after a root canal. This pain usually responds very well to pain medication and can be managed well.

Your tooth may be sensitive for a few days after the treatment, but the acute pain will be gone. Over-the-counter pain relievers generally work well for pain relief at this point. To restore your tooth to its fully-functioning state, a crown or other restoration is usually needed after root canal treatment. Properly done, the restored tooth can last as long as any of your natural teeth.

Yes. You can relieve the pain by having the tooth removed. But you don’t want to go there. Tooth loss can lead to unwanted side effects, like migration of teeth, bone loss and eventually the inability to chew properly. It’s far better to save your natural teeth when you can.