International Journal of Pharmaceutical and Clinical Research 2013; 5(4): 141-144
Antiseptics and Antibiotics Used in Regenerative Endodontics
Saveetha Dental College and Hospitals, Saveetha University, Chennai, Tamil Nadu, IndiaAvailable online: 17th September, 2013ABSTRACT Contemporary endodontics and the future of endodontics are based on regenerative strategies. Success of these regenerative endodontic treatments depends on disinfection of the root canal system. Current research in endodontics focuses on identifying the optimal methods of disinfection of root canal systems to achieve predictable results in revascularization therapy. Although the use of sodium hypochlorite for disinfection is mandatory, additional intracanal medicaments are also required to realize this goal. This article reviews the antiseptics and antibiotics used for achieving disinfection of root canals for regenerative procedures. Key words: regenerative endodontics, revascularization, disinfection, sodium hypochlorite, antibiotics, chlorhexidine. INTRODUCTION
the irrigants and medicaments. This may be likened to the
Regenerative endodontic procedures can be defined as
Lesion sterilization and tissue repair (LSTR) therapy
biologically based procedures designed to replace
which employs the use of a combination of antibacterial
damaged structures, including dentin and root structures,
drugs for the disinfection of pulpal and periradicular
as well as cells of the pulp-dentin complex. The
objectives of regenerative endodontic procedures are to
Antiseptics used for disinfection in regenerative
regenerate pulp-like tissue, ideally, the pulp-dentin
complex; regenerate damaged coronal dentin, such as
following a carious exposure; and regenerate resorbed
Hypochloric acid disrupts several vital functions of the
root, cervical or apical dentin 1. One of the presently
microbial cell, resulting in cell death. NaOCl is
viable regenerative procedures is revascularization of the
commonly used in concentrations between 0.5% and 6%.
root canal. This is done via a blood clot that is induced by
It is a potent antimicrobial agent, killing most bacteria
over-instrumentation of the root canal system. The
instantly on direct contact. It also effectively dissolves
revascularization treatment is the disinfection of the root
components of dentin. Hypochlorite is the only root canal
canal space 2. This article reviews the various agents used
irrigant of those in general use that dissolves necrotic and
for root canal disinfection during revascularization
vital organic tissue. In some articles hypochlorite is
treatment, along with a review of literature assessing
reported to kill the target microorganisms in seconds,
even at low concentrations, although other reports have
Need for disinfection during revascularization
published considerably longer times for the killing of the
The rationale of revascularization is that if a sterile tissue
same species. It has been shown that 0.5% or 5% NaOCl,
matrix is provided in which new cells can grow, pulp
with or without EDTA for irrigation, resulted in
vitality can be reestablished. Revascularization protocols
considerable reduction of bacterial counts in the canal
are derived from the observations of reimplanted and
when compared with irrigation with saline 4. This is in
auto- transplanted teeth in experimental animals in which
accordance with several published reports on the
necrotic pulp, devoid of infection, provide a matrix into
antibacterial activity of sodium hypochlorite in vitro.
which the cells from the periradicular region could grow
Hypochlorite is also the only irrigant capable of brining
about destruction of root canal biofilms 5-7.
This sterile matrix that is created is the key to success of
In vivo, the antimicrobial effectiveness of NaOCl is
treatment. One area wherein maximum research is being
limited. The poorer in vivo performance compared with
carried out in the field of revascularization is the different
in vitro is probably caused by problems in penetration to
antimicrobial agents used as intracanal medicaments to
the most peripheral parts of the root-canal system such as
bring about the disinfection. Since almost no
fins, anastomoses, apical canal and lateral canals. Also,
instrumentation is carried out (in contrast to routine root
the presence of inactivating substances such as exudate
canal treatment where disinfection is brought about by
from the periapical area, pulp tissue, dentin collagen, and
the action of instruments synergistically with irrigants),
microbial biofilms counteract the effectiveness of NaOCl
the disinfection protocol relies on the chemical actions of
8. Long term exposure of dentin to a high concentration of
*Author for correspondence: E-mail: prasanna_neelakantan@yahoo.comNabeel Ahmed, Prasanna Neelakantan / Antiseptics and Antibiotics…
sodium hypochlorite can have a detrimental effect on
the antibacterial agent in revascularization treatment,
dentin elasticity and flexural strength, based on some in
resulted on continued root development at the end of 24
vitro studies 9,10. Considering this limited antibacterial
months 18. Also, in contrast to calcium hydroxide, CHX
activity in lieu of the anatomical complexities of the root
did not cause obliteration of the root canal space by
canal space, intracanal medicaments are used for
calcification. The root development was also reported to
antimicrobial action. However, the use of sodium
be faster than when other materials were used for root
hypochlorite in endodontics in general and in
revascularization treatment, in particular is to be
Root canal infections are polymicrobial, consisting of
both aerobic and anaerobic bacteria. Because of the
Regenerative dental procedures have a long history,
complexity of the root canal infection, it is unlikely that
originating around 1952, when Dr. B. W. Hermann
any single antibiotic could result in effective sterilization
reported on the application of calcium hydroxide in a case
of the canal. A combination would be needed to address
report of vital pulp amputation. Calcium hydroxide has
the diverse flora encountered. The most commonly used
been used commonly as an intracanal medicament. This
medicament is a combination of three antibiotics, referred
is mainly due to its high alkaline pH (about 11.5 - 12),
to as a triple antibiotic paste (TAP). This formulation was
which results in its antibacterial action. The disinfecting
first used by Sato et al. and contains metronidazole,
action of calcium hydroxide is effective for at least for
ciprofloxacin, and minocycline. This combination is
one week and the effect drastically reduces thereafter 11.
commercially available as 3-MIX MP 19.
Furthermore, calcium hydroxide has three important
Metronidazole is a nitroimidazole compound. It is
disadvantages: it is ineffective against Enterococcus
selectively toxic to anaerobic microbes. It also exhibits
fecalis which is the predominant microbe isolated in
broad spectrum antimicrobial activity against against
failed root canal treatment 12; it is known to weaken the
protozoa and anaerobic bacteria. The presence of certain
root structure 13 and, complete removal of the material is
redox proteins reduces the nitro group of this compound
extremely difficult if not impossible 14. Of these
and generates free radicals that enter the cell and induce
disadvantages, a point of concern in regenerative
DNA damage. This results in rapid cell death 20.
strategies is the potential weakening of tooth structure by
this material. Revascularization strategies are employed
minocycline are primarily bacteriostatic, inhibiting
in immature teeth with open apices, and these teeth
protein synthesis by binding to 30S ribosomes in
inherently have thin dentinal walls that are predisposed to
susceptible organisms. They exhibit broad spectrum of
activity against gram positive and gram negative
It was also shown by Banchs and Trope that the stem
cells at the periradicular region following differentiation
derivative of tetracycline with a similar spectrum of
result in continued root formation. These cells also help
antibacterial activity. Tetracycline inhibits collagenases
in res-establishing the vascularity of the pulp. Calcium
and matrix metalloproteinases,and is not cytotoxic. It also
hydroxide is cytotoxic to the cells of any viable pulp
tissue and the stem cells from the apical papilla. This
inflammatory cytokine 21, 22. Ciprofloxacin is a synthetic
would be detrimental to the revascularization process 15.
floroquinolone with rapid bactericidal action. It inhibits
the enzyme bacterial DNA gyrase, which nicks the
A recent report showed the efficacy of a 2%
double stranded DNA, introduces negative supercoil and
chlorhexidine gel in the revascularization treatment.
then reseals the nicked end. The bactericidal action
Chlorhexidine (CHX) has antimicrobial properties and
probably results from digestion of DNA by exonucleases
low cytotoxicity. It is also effective against most
whose production is signaled by the damaged DNA. It
endodontic pathogens. CHX permeates the microbial cell
exhibits very potent activity against gram negative
wall or outer membrane and attacks the bacterial
bacteria but very limited activity against gram positive
cytoplasmic or inner membrane or the yeast plasma
bacteria. Most of the anaerobic bacteria are resistant to
membrane. In high concentrations, CHX causes
ciprofloxacin. Hence it is often combined with
coagulation of intracellular components 16. Removal of
the material is easy and the most importantly, the material
Metronidazole and ciprofloxacin can generate fibroblasts,
exhibits substantivity ie., the antibacterial action is long-
all of which will enhance success of the regenerative
procedure 21-23. It has also demonstrated that while each
Chlorhexidine is also a matrix metalloproteinase inhibitor
of these antibiotics did not result in complete bacterial
17. MMPs have been shown to be agents of tissue
destruction and markers of inflammation. However,
similar to other endodontic disinfecting agents, the
Hoshino et al. recommended a ratio of 1:1:1 of
activity of CHX depends on the pH and is also greatly
metronidazole (500 mg), minocycline (100 mg) and
reduced in the presence of organic matter.
ciprofloxacin (200 mg) for the 3Mix formulation. The
Chlorhexidine may be a safe alternative if this medication
carrier or vehicle recommended was propylene glycol, in
came into contact with periapical tissues in immature
the ratio 1:1, with polyethylene glycol or macrogol. This
teeth. CHX, in a clinical study showed that, when used as
combination is termed MP 23. The standard recommended
IJPCR, October-December, 2013, Vol 5, Issue 4, 141-144
Nabeel Ahmed, Prasanna Neelakantan / Antiseptics and Antibiotics…
mix contains 1 part of MP mixed with 7 parts of 3Mix.
Murray PE, Garcia-Godoy F, Hargreaves KM.
This formulation was modified by Takushige et al., who
Regenerative endodontics: A review of current status
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3:3:1, wherein 3 parts of metronidazole and 3 parts of
Jung IY, Lee SJ, Hargreaves KM. Biologically based
minocycline are mixed with 1 part of ciprofloxacin. This
treatment of immature permanent teeth with pulpal
can be mixed with MP or root canal sealers. However, the
necrosis: a case series. J Endod 2008; 34 (7), 876–
mixture with sealers is presently not recommended 24.
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Hoshino E, Takushige T. LSTR 3Mix-MP method-
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CONCLUSIONS
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A Rapid iMethod™ Test for the Analysis of Four Immunosuppressant Drugs Utilizing Direct Injection LC/MS/MS iMethod™ Test for Immunosuppressants Version 1.0 for Cliquid® Software The following description outlines the instrument requirements Samples are prepared using a protein precipitation step, and expected results obtainable from the AB SCIEX iMethod™ centrifuged then injec
TABLE OF CONTENTS Stress & Illness – A ‘Job-Strain’ ModelCoping with Stress – A 5-Step FrameworkCoping with Stress – Physical TechniquesCoping with Stress –Behavioral TechniquesCoping with Stress – Diversion TechniquesCoping with Stress – Workplace Techniques Purpose of this Handbook The handbooks on Soft Skills developed by Centre for GoodGovernance are intended pr