Root Canals (aka Endodontic Treatment)

Dentists are paid by how many canals are treated. Molars usually have three canals (but sometimes 4 and very rarely 5), premolars may have one or two, and front teeth usually have one canal.

Treatment time may vary from 30 minutes to 2 hours, rarely more. A filling repair then needs to be added on with additional time and expense. Most root canalled teeth need a crown on afterwards due to the extent of damage they have suffered to reach the state of requiring this procedure in the first place.

Teeth are blocks of calcium with nerves running through them. Every nerve in the body has a blood vessel running beside it providing oxygen, nourishment and to remove waste products. The nerve and blood vessel matrix inside a tooth is called the pulp tissue. If bacteria get into this area this tissue dies.

The problem is the flow of blood inside of teeth is small and slow moving. Once bacteria get into a tooth there is an inflammatory response similar to getting a sliver in your finger.

The problem with teeth is that as the tissue becomes inflamed it tries to swell. But teeth are hard blocks of calcium and cannot expand to accommodate the swelling. So Pressure builds up inside the tooth. Pressure leads to pain. The pain is often very intense. This is the early acute phase. As pressure builds up soft blood vessels are squeezed shut. With blood cut off there is no more oxygen and nourishment as well as no waste removal. The tissue in here dies becoming Necrotic. The bacteria in here now have a safe place to live and grow as there are no white blood cells to fight them. They eventually spread down the nerve canals out into the jaw bone where they can cause visible swelling in the face. Certain areas can be life threatening if it blocks the airway or goes into the brain area.

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Healthy Tooth

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Infected tooth

Pain
Usually there is lots of pain associated with this process initially. Occasionally the tissue breaks down slowly with only minor discomfort or pain that is either tolerable or ignored. Then the bacteria spread out the end of the root and will cause lots of problems but occasionally will quietly make a little tunnel out through the gum and form a little pimple which is basically just the exit point where it drains. The body may “wall off” a slowly growing bacteria population at the end of the tooth and create a kind of fluid filled bag. Or the body will sacrifice some of its own bone at the end of the root and fill it with white blood cells to fight the bacteria as they come out of the root tip.

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On the x-ray of this area there is always a dark halo around the root tip that starts very small but can get very big and require surgery to repair.

Treatment
A root canal involves cleaning everything out of all the canals in every root of a tooth. Small files are used to scrape out bacteria and other canal remnants to enlarge the canals slightly to allow disinfectant to penetrate to the ends of the canals. We want to sterilize the canals as thoroughly as possible so bacteria cannot live in these areas. Then the canals are filled with a material called gutta percha which is a kind of inert latex like material which restricts bacteria from re-infecting the area. Now the body can heal the area at the end of the root and regrow the bone.

The nerve tissue inside teeth is strictly sensory and gives the brain info about hot, cold, or pain. Teeth don’t need nerve tissue in them for them to stay anchored in the socket.  This is just how we are built.

The outside of the roots are attached in the socket by miniature ligament fibers that attach to the surrounding bone; this is separate from the inside canals.

Root Canal Failure and Retreatment
Root canal treatment may be compromised if the bacteria are not removed completely due to inadequate disinfecting or missed canals. Other problems can be perforated roots or lost files early on in the procedure (as opposed to late where disinfectant has done its job and the lost file can act as a seal). The only other way to cure an infected tooth is to remove it. But extracting a tooth increases the pressures on the remaining teeth. This can have other ramifications in the remaining dentition. Extraction can be far more expensive in the long term.