Antimicrobial Effect of Debridement

The control of bacteria within the root canal might appear to be straightforward since such a large proportion of the bacterial flora is sensitive to oxygen. However, the penetration of oxygen into the canal during treatment does not seem to have any significant effect on the bacteria. The reason for this is that many of the bacteria are protected in the irregularities and branches of the root canal system and in dentinal tubules. Only a few cells need to survive treatment so that when the canal is closed, the anaerobic milieu will be restored and the bacteria can remultiply.

The microbial flora within the root canal must be actively eliminated by a combination of physical debridement and antimicrobial chemical treatment. Although the most important aspect of root canal instrumentation is undoubtedly the elimination of bacteria and the removal of remnants of pulp tissue and debris, the shaping of the root canal to accommodate the root filling material is also of importance.

Preparation of the root canal consists of two main phases: debridement by manual and mechanical instrumentation and chemical disinfection by irrigation and subsequent antibacterial dressing.