The perfect filling of a root canal should completely fill and seal the canal to the very tip of the root.

With all the research done on by untold numbers of investigations, this ideal has yet to be accomplished.

Keep in mind that any space not occupied by the root canal filling can be contaminated by the ingress of bacteria often present in the bloodstream and by bacteria present in dentin tubules.

The fact that 30 percent of people with root canal fillings were free of complicating degenerative disease does not alter the concern about the continuing presence of bacteria in their root filled teeth. To the 70 percent who are suffering health problems, inadequately filled root canals add insult to injury.

Most of the spaces remaining after filling are due to shrinkage of the root filling material.

Gutta-percha, still the most widely used root filling material, was scientifically tested by Dr. Price using a packing device he invented to eliminate usual packing technique difficulties, yet not a single test filling was free of leakage.

A 1984 report in the Journal of Endodontia of a new material, cyanoacrylate, used along with gutta-percha, found leakage cut down to 0.5 millimeters of space. Though a big improvement, that still represents a significant cave-like dwelling area for organisms to accumulate, from which bacteria can sneak back into the general circulation and cause body harm.

Dr. Price devised a test using healthy extracted teeth, which demonstrated how these spaces in root fillings, even if sterile initially, could become infected from blood circulation.

Dr. Price stated that neither root fillings nor sterilization procedures needed to be perfect, providing the patient's immune system was adequate enough to meet such challenges.