Root Canal Microbiology

ABSTRACT: Sodium hypochlorite (NaOCl), a reducing agent, is a clear, straw coloured solution containing about 5% available chlorine. It is the most widely used irrigating solution. NaOCl on ionization produces hypochlorous acid and hypochlorite ion. These are responsible for the antimcrobial ability of the same. No unanimity of opinion exists as to which concentration of NaOCl can be used in root canal therapy. On the basis of published data, 0.5- 5.2%  solution is an effective concentration for the use as an irrigant in the root canal. If the canal is filled with the solution during the entire cleaning and shaping procedures, the irrigant will act as an lubricant, solvent to the pulpal tissues and a potent antimicrobial of a no. of solution studied , none was more effective than 5.2% solution of NaOCl. However 2.5% concentration of the same is commonly employed as it decreases the potential for toxicity while maintaining some tissues dissolving and antimicrobial activity. The following article deals with the various accidents caused by misuse of sodium hypochlorite and their management.
KEY WORDS: Accident, irrigation, sodium hypochlorite(NaOCI), prevention.
| Dr VINEET VINAYAK | dr VINEET vinayak

Introduction: Successful endodontic treatment
outcomes require new strategies for the complete eradication
of microbial biofilms in the root canal system.
Matrix metalloproteinases (MMPs) are essential enzymes
in microbial cell growth and homeostasis, and
they require transition metal ion cofactors to function.
Targeting MMP activity also preserves dentin collagen
integrity. In this study, 1,10-phenanthroline-5,6-dione
(Phendione), a metal chelator, was tested as a potentially
novel antimicrobial agent against Enterococcus
faecalis and inhibitor of human MMP in the root canal.
Methods: Minimum inhibitory concentration (MIC) and
minimum bactericidal concentration (MBC) of Phendione
on E. faecalis were determined. The antimicrobial
properties of Phendione in the presence of dentin
powder and various transition metal ions were examined.
The ability of Phendione to inhibit human MMP-
2 was subsequently tested. The efficacy of Phendione
against E. faecalis biofilm was determined by exposure
of 7-day-old E. faecalis biofilms to Phendione.
Results: The MIC and MBC of Phendione were 2.0
mg/mL and 16 mg/mL, respectively, whereas 64 mg/mL
was required to kill E. faecalis biofilm. Phendione
completely eradicated E. faecalis despite dentin preincubation.
The presence of Zn2+, and to a lesser extent
Fe2+, abrogated the antimicrobial effect of Phendione.
In addition, Phendione at MIC and MBC significantly
inhibited human MMP-2 activity. Conclusions: Phendione
effectively eradicated E. faecalis biofilms and
significantly inhibited human MMP-2 through its ability
to chelate metal ions. The antibacterial property of
Phendione was preserved in the presence of dentin.
Phendione can potentially be applied in endodontic
treatment as both an antimicrobial agent and MMP inhibitor.