Imagine a "ball point pen".  There is an ink cartridge inside the pen one can remove leaving the pen hollow.  Now, fill in this hollow space with a rubber-like filling material and you have just root canaled a ball-point-pen.  Our roots of our teeth extend into the bone supporting our teeth.  These roots have a canal inside similar to the ink cartridge in the pen.  When we do a root canal, the contents in the "canal" ( consists of the nerve and blood vessel supplying our teeth with nutrition and sensations) are removed just as one would remove the ink cartridge.  After cleaning out the canal, we fill it back up with a rubber like filling which seals the canal.

The "roots" are not removed as many people think.. Only the inside of the root is cleaned out so the root into the bone is unchanged and still supports the tooth.  This is the benefit of a root canal......A tooth can be saved and still function normally following a root canal.

The only option to a root canal is to have the tooth extracted hence, the beauty of a root canal.