The species commonly recovered by culture from
root canals of teeth with apical periodontitis have been
described in a previous review.
Because the root canal
environment and nutritional supply govern the
dynamics of the microbial flora, it means that the
bacteria present in the root canal will depend on the
stage of the infection.
Initially, there may be no clear associations between
bacteria, but strong positive associations develop
among a restricted group of the oral flora due to the
type of nutrients in the environment.Thus,
F. nucleatum is associated with P. micros, P. endodontalis
and C. rectus.
Strong positive associations exist
between P. intermedia and P. micros
and Peptostreptococcus anaerobius.
There is also a
positive association between P. intermedia, and P. micros,
P. anaerobius and the eubacteria.
In general, species of
Eubacteria, Prevotella and Peptostreptococcus are
positively associated with one another in endodontic
samples.
Properties that these bacteria have in
common are that they ferment peptides and amino
acids and are anaerobic,
which indicates that the main
source of nutrition in root canals are tissue remnants
and a serum-like substrate.
Bacteria in a root canal infection do not occur in vivo
as separate colonies, but grow within an extracellular
matrix in interconnected communities as a bacterial
biofilm. An accurate depiction of the ultrastructural
appearance of these biofilms in the infected root canal
was first reported by Nair,
who described them as co-aggregating communities with a palisade structure.
The clinical significance of a biofilm growth pattern is
that bacteria are relatively protected within the co-aggregated community compared with planktonic
forms and are known to be more resistant to
antimicrobial treatment measures.
Currently, limited
information is available on the development, physiology
and antimicrobial management of biofilms in the root
canal, however this area should provide a fruitful
subject for future research.
root canals of teeth with apical periodontitis have been
described in a previous review.
Because the root canal
environment and nutritional supply govern the
dynamics of the microbial flora, it means that the
bacteria present in the root canal will depend on the
stage of the infection.
Initially, there may be no clear associations between
bacteria, but strong positive associations develop
among a restricted group of the oral flora due to the
type of nutrients in the environment.Thus,
F. nucleatum is associated with P. micros, P. endodontalis
and C. rectus.
Strong positive associations exist
between P. intermedia and P. micros
and Peptostreptococcus anaerobius.
There is also a
positive association between P. intermedia, and P. micros,
P. anaerobius and the eubacteria.
In general, species of
Eubacteria, Prevotella and Peptostreptococcus are
positively associated with one another in endodontic
samples.
Properties that these bacteria have in
common are that they ferment peptides and amino
acids and are anaerobic,
which indicates that the main
source of nutrition in root canals are tissue remnants
and a serum-like substrate.
Bacteria in a root canal infection do not occur in vivo
as separate colonies, but grow within an extracellular
matrix in interconnected communities as a bacterial
biofilm. An accurate depiction of the ultrastructural
appearance of these biofilms in the infected root canal
was first reported by Nair,
who described them as co-aggregating communities with a palisade structure.
The clinical significance of a biofilm growth pattern is
that bacteria are relatively protected within the co-aggregated community compared with planktonic
forms and are known to be more resistant to
antimicrobial treatment measures.
Currently, limited
information is available on the development, physiology
and antimicrobial management of biofilms in the root
canal, however this area should provide a fruitful
subject for future research.