In vitro disinfection of dentinal tubules by various endodontics irrigants

Effectiveness of endodontic irrigants within dentinal tubules of human teeth was evaluated. Mid-sections of single-rooted teeth were prepared into dentin wedges. The pulpal sides of the sections were exposed to Micrococcus luteus or Bacillus megaterium that grew into the tubules. Irrigants used in the study included: 0.525% NaOCl, 0.12% chlorhexidine, RC Prep, 0.5% betadine iodine, and sterile H2O (as a control). Pulpal surfaces were exposed to an irrigant and then rinsed in sterile water. The samples were then cracked, exposing a fresh surface. Culture of the exposed dentin surfaces showed that selected irrigants reached to the far ends of the dentinal tubules in a concentration sufficient to kill 100% of the M. luteus. However B. megaterium was neither killed nor apparently inhibited by any irrigant. We conclude that endodontic irrigants permeate throughout dentinal tubules, but their effectiveness is dependent on the type of bacteria found within the tubules.