
This is an example of a back tooth that developed a cyst, which is shown by the dark area around the tip of the root. A root canal was performed and you can see some of the root canal filling material in the dark area, which represents an accessory canal. The prognosis for this tooth is good because the accessory canal was found and filled.

This is another example of an accessory canal in a back tooth. This canal, which is shown by the arrow, was rather large. The prognosis for this tooth is also good because the accessory canal was found and filled.

This is an x-ray of an upper molar with four canals, which is not very common. What makes the treatment of this tooth more difficult is the curvy nature of its canals.

The four canals have been labeled. Canal #1 is very straight but the other three canals, especially #3, are curved. Each canal must be free of any nerve or blood tissue before it is filled to ensure a good prognosis.

Most of the canals, where the nerve and blood vessels of the tooth reside, are narrow like the wick in a candle. Some canals are very wide, which is shown in this x-ray of a front tooth. All this means is that there is less tooth structure surrounding the canal, which can mean the tooth is weaker than if the canal were narrower.

The tooth on the right is what we typically expect to see in regard to a normal root canal anatomy, which for this tooth is three separate canals. The tooth on the left has only one single canal, which is why the filling material appears so wide. The internal anatomy of each tooth is different, which makes each root canal procedure unique.

This is an x-ray of an upper front tooth. The root on this tooth is shorter than normal. What is happening here is that the cells of the root of the tooth are being eaten away in a process that is called external resorption. This process usually occurs very slowly over a matter of months or years and is usually associated with some sort of trauma to the tooth. The dotted line on the left image above indicates an infection from the left tooth. The dotted line on the right image above represents that portion of the root of the tooth that has been lost due to the resorption.

The treatment for this is to do a conventional type of root canal procedure, which may take one or two visits. This procedure is a last attempt at saving the tooth. The success of this procedure depends upon when the resorption is diagnosed and treated, and how long the root of the tooth is and the health of the surrounding bone. An annual exam with x-rays is the only way to check on the prognosis of the tooth. In the case above, both teeth showed signs of resorption, which is why they were each treated with a root canal.

This is an x-ray of a back tooth known as a molar, which was taken immediately after root canal treatment. The arrow is pointing to a dark area, which is the sign of an infection.

This x-ray was taken approximately one year after the root canal treatment. Notice that the dark area has filled in with bone, which tells us that the root canal was successful. The large white area on the top portion of the tooth is a crown, which is required treatment for almost all back teeth that have a root canal.

The yellow arrow above indicates internal resorption. This is where the cells inside the tooth destroy the root from the inside out. This process usually occurs very slowly over a matter of months or years and is usually associated with some sort of trauma to the tooth.

The treatment for internal resorption usually takes a couple of appointments. First, a medicated filling is placed and then, after a few weeks, the medicated filling is removed and the procedure is completed in the conventional way. This type of condition requires annual examination by x-ray to check on the tooth. The prognosis is fair to poor but the only other option is to extract the tooth.

The dark area around the entire root of the tooth above indicates the presence of a large infection.

Conventional root canal treatment was performed and this is an x-ray of the tooth about six months later. You can see the dark infected area has disappeared and has been replaced by healthy bone structure. The prognosis for this tooth is excellent.