["In vitro" analysis of the dentin permeability of the apical third of the root as a function of changes in auxiliary chemicals used in instrumentation].

: We analyzed the possible percentage variations of dentinal penetration of the methylene blue solution in the apical third, in human teeth pulled out, after it's preparation, utilizing files type K-Flex, and five auxiliary chemical substances. Results have shown that there is a significant difference among the percentage of the dye penetration and among the auxiliary chemical substances used for the chemical-mechanic preparation. We can also prove true that, for apical region, the Endo PTC was the one that showed the greatest percentage of penetration.