The standard method of filling root canals is based on the theory that it is most important to seal up the main root canal space and prevent future invasion of bacteria into the tooth. Such a root filling is like a cork and is made of a rubber like material called gutta percha. They have an excellent record of getting rid of pain and acute infection.
There is more to the root of a tooth than the main channel of the root canal, and the alternative method of filling root canals is based upon this anatomical fact. The majority of the tooth is called dentin, which is extremely porous and contains thousands of microscopic tubules as seen in the picture below. The bacteria that cause the tooth to be infected get into these porous spaces and are not affected by a root filling that is only put into the main canal. They can remain in the tooth, excreting waste products that can add to immune and toxic stress in susceptible people.
The alternative method of filling root canals is an FDA approved product called Endocal 10. It originated in France and has been used in other countries for over 15 years. Endocal 10 is manufactured and sold by the Biodent company of Montreal. It consists of a powder of calcium oxide and zinc oxide, which have been demonstrated to be among the most biocompatible materials used in dentistry.
This is a microscopic image of a root in cross-section. “A” represents the outer root surface. “B” shows the millions of dentinal tubules where bacteria can remain after root canal treatment. The empty space in the bottom right corner is the main canal space. It normally contains the living tissue of the tooth (i.e. nerves, blood vessels, and other cells). This main canal is cleaned and filled when root canal treatment is performed.