Infection of the root canal is not a random event. The
type and mix of the microbial flora develop in response
to the surrounding environment. Factors that influence
whether species die or survive are the particular
ecological niche, nutrition, anaerobiosis, pH and
competition or cooperation with other micro-organisms.
Whether it is a necrotic pulp or root-filled
space, the environment selects for micro-organisms that
possess traits suited to establishing and sustaining the
disease process.
Reduction and elimination of micro-organisms from
the infected root canal provides the optimal chance of
treatment success. The goal of achieving a clean,
microbe-free canal can best be realised by working in a
sterile way using instrumentation with antibacterial
irrigation, which is reinforced by an intracanal dressing
with calcium hydroxide. Alternating regimes of sodium
hypochlorite solution and EDTA during canal
preparation followed by dressing with calcium
hydroxide for a minimum of seven days are a powerful
combination for elimination of bacteria from the root
canal. Provided sufficient time is available for canal
preparation at the first visit and filling of canals at the
second, endodontic treatment can be completed in just
two visits with the assurance that there is a high chance
of eliminating bacteria from the root canal system