Enterococcus faecalis -An Endodontic Challenge

MTAD (a mixture of tetracycline isomer,acid
and detergent):MTAD is a formulation of
doxycycline, citric acid and Tween 80. Its
effectiveness is attributed to its anticollagenase
activity, low pH and ability to be gradually
released overtime. Mahmoud Torabinejad et al
observed that MTAD is effective against
E.faecalis . 7 MTAD is beneficial for retreatment
cases as well.
In one study a combination of calcium
hyrdroxide and camphorated
paramonochlorophenol completely eliminated
E.faecalis.Metapex (a silicone oil-based calcium
hydroxide paste containing 38% iodoform),
more effectively disinfected dentinal tubules
infected with E.faecalis than calcium hydroxide
alone. 2% chlorhexidine gel when combined
with calcium hydroxide achieves a pH of 12.8
and can completely eliminate E.faecalis within
dentinal tubules. Chlorhexidine and calcium
hydroxide when combined together have
shown better antimicrobial properties than
calcium hydroxide alone. 8
Nair, et al suggested the need of non antibiotic
chemomechanical measures to treat teeth with
infected and necrotic root canals so as to
disrupt the biofilm.
Er:Cr:YSGG laser employing radially emitting
laser tips demonstrated a considerable effect
on bacterial reduction within dentinal tubules
of root canal infected with E.faecalis. 9
Roth 811 sealer ,a zinc –oxide eugenol based
sealer has been shown to exert antibacterial
activity against E.faecalis.AH Plus (epoxy resin
based sealer) and Grossman’s sealer are
effective in killing E.faecalis within infected
dentinal tubules.
Steps that can be considered towards the
elimination and prevention of E.faecalis:
Treatment regimens should aim at prevention
and elimination of E.faecalis during treatment,
inbetween appointments and after completion
of treatment. We can prevent its re-entry by
following certain norms. That includes,
ensuring that the patient rinses with 0 .2%
chlorhexidine prior to the treatment,
disinfecting the tooth and rubber dam with
chlorhexidine or sodium hypochlorite and
disinfecting gutta-percha points with sodium
hypochlorite before insertion in the canal.
Besides the above norms the following can be
followed:
1. Adequate apical preparation
2. Use of canal irrigants such as 6 % sodium
hypochlorite, 17% EDTA and 2% chlorhexidine 4
3. Use of intracanal medicaments such as 2%
chlorhexidine gel or 2% chlorhexidine gel
+calcium hydroxide
4. Consider AH plus or Grossman’s sealer.
5. Proper coronal seal should be given.
Conclusion:
Numerous studies have been conducted on the
effects of various disinfectants on E.faecalis.
Most of them have been invitro. Clinically
E.faecalis still poses to be a challenge.
Endodontists studying root canal infections
need to include endodontic clinical isolates of
E.faecalis to analyze the properties of these
strains which includes putative virulence factors
or antibiotic resistance genes. 10 In order to
develop methods of eradicating E.faecalis from
persistent root canal infections, the mechanism
through which this organism maintains these
infections must be understood. 11
References
1. Shrestha A, Shi Z ,Neoh K G , Kishen A .
Nanoparticulates for antibiofilm
Treatment and effect of aging on its
antibacterial activity. J Endod. 2010; 36
(6) :1030-5.
2. Liu H, Ling J,Wang W ,Huang X. Biofilm
formation capability of Enterococcus
faecalis cells in starvation phase and its
susceptibility to sodium hypochlorite. J
Endod. 2010 ;36 (4): 630-5.
3. Portenier I,Waltimo TMT ,Haapasalo M.
Enterococcus faecalis-the root canal
survivor and ‘star’ in post treatment
disease. Endodontic Topics. 2003; 6:
135-59.
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