Penetration ability of different irrigants into dentinal tubules.

Dentinal tubules of human root canal walls were infected with a known bacterial isolate. The teeth were divided into two groups and the root canals instrumentated. Different types of canal irrigant were used for each group. In group A, 5% NaOCl was followed by a 10% EDTA rinse and neutralized with a final physiological solution rinse. In Group B, 10% EDTA, a tensioactive agent (TRITON), and 5% NaOCl were used in sequence, with a final physiological solution rinse to neutralize the action of the agents used. Histological examination of group A specimens showed a residual area of infection extending from the canal lumen to a mean depth of 300 microns. Histological examination of group B specimens showed an infection-free area of tubules to a mean depth of 130 microns. Below this was an infected area of variable extent. In some group B sections, no infection was found.