Antibiotics in endodontics

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PRESENTED BY:
DR. PREETI RASTOGI
PG 1st year
DEPT. OF CONSERVATIVE DENTISTRY AND ENDODONTICS

ANTIBIOTICS IN ENDODONTICS 2
CONTENTS
Introduction
Classification of antibiotics
The endodontic microbiota
Routes of root canal infection
Types of endodontic infection
Commonly used antibiotic in endodontics
Complications of antibiotic therapy
Antibiotic doses
Use of antibiotic as an intra canal medicament
Conclusion

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Antibiotics are some times necessary for controlling endodontic infections however several
studies from around world have reported over prescription of these drugs.
Inappropriate use of antibiotics not only drives antibiotic resistance and misuses resources; it
also increases the risk of potentially fatal anaphylactic reactions and exposes people to
unnecessary side effects.
In dentistry, antibiotic prescription is empirical because the dentist does not know the specific
microorganisms responsible for the infection, since samples from the root canal or periapical
region are not commonly taken and analysed.
Endodontic infections, are mostly polymicrobial often leading to an empirical prescription of
broad-spectrum antibiotics even in cases where antibiotics are not indicated.
In case of discrete and localized swelling, the primary aim is to achieve drainage without
additional antibiotics.
Antibiotics do not reduce pain or swelling arising from teeth with symptomatic apical pathosis in
the absence of systemic involvement (Keenan et al. 2006, Cope et al. 2014).
ANTIBIOTICS IN ENDODONTICS
INTRODUCTION

Thus, based on clinical and bacterial epidemiological data, the
microorganisms responsible for the infections can only be suspected, and
treatment is decided on a presumptive basis with broad-spectrum
antibiotics often being prescribed .
Therefore, antibiotics should be considered in patients having systemic
diseases with compromised immunity or in patients with a localized
congenital or acquired altered defense capacity.
Medically compromised patients are more susceptible to complication
arising from odontogenic infections and antimicrobials have a more
specific role in their treatment.
Adjunctive antibiotic treatment may be necessary in the prevention of the
spread of infection, in acute apical abscesses with systemic involvement,
and in progressive and persistent infections.
4ANTIBIOTICS IN ENDODONTICS

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Antibiotics are substances produced by
microorganisms, which selectively suppress the
growth or kill other microorganisms at very low
concentrations.

Classification of antibiotics
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Antimicrobial drugs can be classified in following
ways:
A. Chemical structure
B. Mechanism of action
C. Type of organisms against which primarily
active
D. Spectrum of activity
E. Type of action
F. Obtained from

Classification: based on mechanism of action
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1. Inhibit cell wall synthesis: Penicillins, Cephalosporins,
Vancomycin, Bacitracin.
2. Cause leakage from cell membranes:
Polypeptides-Polymyxins, Bacitracin,
Polyenes-Amphotericin B.
3. Inhibit protein synthesis: Tetracyclines, Chloramphenicol,
Erythromycin, Clindamycin.
4. Cause misreading of m-RNA code and affect permeability:
Aminoglycosides-Streptomycin, Gentamicin, etc.
5. Inhibit DNA gyrase: Fluoroquinolones-Ciprofloxacin and others.
6. Interfere with DNA function: Rifampin, Metronidazole.
7. Interfere with DNA synthesis: Acyclovir, Zidovudine.
8. Interfere with intermediary metabolism: Sulfonamides,
Sulfones, Ethambutol.

Classification: based on type of organisms against
which primarily active
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Antibacterial : Penicillins, Aminoglycosides, Erythromycin,
etc.
Antifungal : Amphotericin B, Ketoconazole, etc.
Antiviral : Acyclovir, Amantadine, Zidovudine, etc.
Antiprotozoal: Chloroquine, Metronidazole, Diloxanide, etc.
Antihelmintic: Mebendazole, Niclosamide, etc.

Classification: based on spectrum of
activity
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Narrow-spectrum Broad-spectrum
Penicillin G Tetracyclines
Streptomycin Chloramphenicol
Erythromycin

Classification: based on type of action
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Primarily bacterio-static
Sulfonamides Erythromycin
Tetracyclines Ethambutol
Chloramphenicol Clindamycin
Primarily bactericidal
Penicillins Cephalosporins
Aminoglycosides Vancomycin
Polypeptides Nalidixic acid
Rifampin Ciprofloxacin
Isoniazid Metronidazole
Pyrazinamide Cotrimoxazole
Some primarily static drugs may become cidal at higher concentrations (as attained in the
urinary tract), e.g. sulfonamides, erythromycin, nitrofurantoin. On the other hand, some cidal
drugs, e.g. cotrimoxazole, streptomycin may only be static under certain circumstances.

Classification: based on it obtained from:
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Fungi
Penicillin Griseofulvin
Cephalosporin
Bacteria
Polymyxin B Tyrothricin
Colistin Aztreonam
Bacitracin
Actinomycetes
Aminoglycosides Macrolides
Tetracyclines Polyenes
Chloramphenicol

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ENDODONTIC MICROBIOTA

Bacterial Genera Represented in Endodontic Infections

Prevalence of bacteria detected in primary endodontic infections of teeth with different
forms of apical periodontitis. Compilation of data from authors’ studies using a molecular
biology technique.

ROUTES OF ROOT CANAL INFECTION
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• Under normal conditions, the dental pulp and dentin are sterile and isolated
from oral microorganisms.
• When the dentin-pulp complex is exposed to the oral environment it is risk
of infection by oral microorganisms.
The main portals of pulp infection are:
• Dentinal tubules following carious exposure
• Through crown or root following traumatic exposure of the pulp.
• Coronal leakage following restorative procedures and restorations
• From the periodontal tissue through exposed dentinal tubules, lateral and
accessory canals, or apical or lateral foramina.
• By the lymphatic or hematogenous route.

Ecology of the Endodontic
Microbiota
• The necrotic root canal is a fertile environment
for bacterial growth and colonization.
• The key ecologic factors that influence the
composition of the microbiota in the necrotic root
canal are:
• OXYGEN TENSION AND REDOX
POTENTIAL
• AVAILABLE NUTRIENTS
• BACTERIAL INTERACTIONS

Ecological conditions in different areas of root canal

Oxygen Tension and Redox Potential
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• In the initial phases of the pulpal infectious process,
facultative bacteria predominate.
• After a few days or weeks, oxygen is depleted within
the root canal as a result of:
 Pulp necrosis and
 Consumption by facultative bacteria.
• An anaerobic milieu with consequent low redox
potential develops, which favors the survival and
growth of obligate anaerobic bacteria.
• Finally, anaerobic conditions become even more
pronounced, particularly in the apical third of the root
canal, and as a consequence, anaerobes will dominate
the microbiota and out number facultative bacteria.

Available Nutrients
• In the root canal system, bacteria can utilize the following
as sources of nutrients:
(1) the necrotic pulp tissue,
(2) proteins and glycoproteins from tissue fluids and
exudate that seep into the root canal system via apical and
lateral foramens,
(3) components of saliva that may coronally penetrate in the
root canal, and
(4) products of the metabolism of other bacteria.
Most of the infecting microbiota, particularly fastidious
anaerobic species are located in main canal which is most
voluminous thus having largest amount of available
nutrients.

Bacterial Interactions
• The establishment of certain species in the root
canal is also influenced by interactions with other
species.
• Positive interactions (mutualism and
commensalism) enhance the survival capacity of the
interacting bacteria and increase the probability of
certain species to coexist in the habitat.
• Negative interactions (competition and antagonism)
limit population densities.

Patterns of Microbial Colonization
• The disease process and its effective antimicrobial
therapeutic strategies depend on the way of microbial
cells distributed throughout the infected tissue.
• Bacteria in the root canal system can exist as planktonic
cells suspended in the fluid phase of the main root canal
and as aggregates or coaggregates adhered to the root
canal walls, sometimes forming multilayered biofilms.

• Lateral canals and isthmuses connecting main
canals can be clogged with bacterial cells, primarily
organized in biofilm structures.
• Bacteria forming dense accumulations on the root
canal walls are often seen penetrating the dentinal
tubules.
• The diameter of dentinal tubules is large enough to
permit penetration of most oral bacteria, and tubular
infection is observed in most teeth, evincing apical
periodontitis lesions

TYPES OF ENDODONTIC INFECTIONS
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Endodontic infections can be classified according to the anatomic
location:
• Extra radicular Infection
• Intra radicular Infection
Intra radicular infections can in turn be subdivided into three
categories:
oPrimary Intraradicular Infection
oSecondary Intra radicular Infection
oPersistent Intraradicular Infection

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Primary Intra radicular Infection
• Microorganisms that initially invade and colonize the necrotic pulp
tissue cause primary intra radicular infection.
• Primary infections are characterized by a mixed consortium
composed of 10 to 30 bacterial species.
• The involved microbiota is conspicuously dominated by anaerobic
bacteria, but some facultative or micro aerophilic species can also
be commonly found in primary intra radicular infections.

Secondary Intra radicular Infection
• Microorganisms introduced into the root canal system at
some time after professional intervention cause secondary
intra radicular infections.
• The main causes of microbial introduction in the canal
during treatment include remnants of dental plaque,
calculus, or caries on the tooth crown; leaking rubber dam;
or contamination of endodontic instruments, irrigating
solutions, or other intra canal medications.
• Microorganisms can enter the root canal system between
appointments and after root canal filling by:
 Loss or leakage of temporary restorative materials,
By fracture of the tooth structure,
Teeth left open for drainage, recurrent decay exposing the root canal
filling material, or delay in placement of permanent restorations.

Persistent Intra radicular Infection
• Microorganisms that can resist intra canal antimicrobial
procedures and endure periods of nutrient deprivation in a
prepared canal cause persistent intra radicular infections.
This is also termed recurrent infection.
• Involved microorganisms are remnants of a primary or
secondary infection, composed of gram-positive facultative
or anaerobic bacteria.
• Persistent and secondary infections are for the most part
clinically indistinguishable and can be responsible for
several clinical problems, including persistent exudation,
persistent symptoms, inter appointment flare-ups, and failure
of the endodontic treatment characterized by a post treatment
apical periodontitis lesion.

Extra radicular Infection
• Extra radicular infection is characterized by microbial
invasion and proliferation in the inflamed periradicular
tissues.
• Extraradicular infection can be dependent on or independent
of the intra radicular infection.
• The most common form of extra radicular infection
dependent on the intra radicular infection is the acute apical
abscess.
• The most common form of extra radicular infection that can
be independent of the intraradicular infection is the apical
actinomycosis.
• The dependent or independent extra radicular infection
assumes special relevance from a therapeutic standpoint
because the former can be successfully managed by root canal
therapy, whereas the latter can only be treated by endodontic
surgery.

SYSTEMIC USE OF ANTIBIOTICS IN
ENDODONTIC INFECTIONS

SYSTEMIC USE OF ANTIBIOTICS IN
ENDODONTIC INFECTIONS
• Adjunctive antibiotic strategies may be needed in cases where there
is abscess formation.
•While in case of discrete and localized swelling, drainage by itself is
considered sufficient.
•Antibiotics are unnecessary in the cases :
 irreversible pulpitis,
necrotic pulps, and
localized acute apical abscesses
Because these scenarios lack of blood circulation in the root canal
prevents antibiotics reaching the area, that is, they are ineffective in
eliminating the microorganisms.

Antibiotics are useful adjuncts in specific cases as they assist in the
prevention of the spread of infection.
•Thus it is necessary:
 To identify these specific cases,
Specific antibiotic
Dose and duration of adjunct antibiotics
•The development of cellulitis in cases of acute apical abscess in which
the transudate and exudate spreads via interstitial and tissue spaces. In
such cases, incision for drainage is of utmost importance because of its
twofold advantages:
the relief of the patient by the removal of toxic products and,
for the antibiotic to penetrate into the infected space more readily.

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•The selection of a specific antibiotic is generally based on:
 empirical criteria and
on the types of bacteria most frequently isolated from periapical
lesions, which are often facultative or anaerobic in nature.
Culturing for identification and antibiotic susceptibility testing
especially for medically compromised and immuno-compromised
patients.

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No ! Indication for antibiotics as an adjunct to
endodontic therapies
Pulp/periapical condition Clinical/ Radiographic data
Symptomatic irreversible pulpitis •Pain
•No other symptom and signs of infection.
Pulp necrosis •Non vital teeth
Acute apical periodontitis •Pain
•Pain to percussion and biting
Chronic apical abscess •Teeth with sinus tract
Acute apical abscess with no systemic
involvement
•Localized fluctuant swelling

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Indication for antibiotics as an adjunct to endodontic
therapies
Pulp/Periapical condition Clinical/ Radiographic data
Acute apical abscess in medically
compromised patient
•Patient with systemic disease causing
impaired immunological function
Acute apical abscess with systemic
involvement
•Elevated body temperature >38 C
•Malaise
•Lymphadenopathy
•Trismus
Progressive infection •Rapid onset of severe infection ( <24 Hrs.)
•Cellulitis
•Osteomylitis
Persistent infection •Chronic exudation which are not resolved
by intra canal procedure and medication.

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Antibiotic recommendations for symptomatic endodontic
patients

Systemic antibiotic use in the treatment
of traumatic injuries of the teeth
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Systemic antibiotic use in the treatment of traumatic injuries of the
teeth
In the cases of Dental injuries among younger individuals, prevention of bacterial
contamination is of great concern as the prognosis may be dramatically affected,
particularly when bacteria are able to access the site of injury and compromise healing.
Inflammatory root resorption is one of the most undesirable complications associated
with traumatic injuries.
Thus, exclusion or limitation of the bacterial load during the healing phase is a logical
approach to obtain the best outcomes in the management of traumatic injuries.
Luxation injuries of permanent dentition IADT guidelines do not recommend the use
of systemic antibiotics in the management of luxation injuries or in teeth with root
fractures.
However, antibiotic administration might be indicated at the discretion of the
clinician when the injury is accompanied by soft tissue trauma requiring intervention.

Based on the International Association of Dental Traumatology (IADT) guidelines
the following recommendations for antibiotic administration.
Systemic antibiotic use in the treatment of traumatic injuries of the
teeth
Traumatic injury Systematic
antibiotic as
adjunct ?
Type of antibiotic
Tooth injury No -
Tooth fracture No -
Concussion/ subluxation No -
Luxation injury of permanent dentition No -
Extrusion No
Replantation of avulsed tooth YES Tetracycline doxycycline

Tooth avulsion
Use Topical antibiotic on a tooth to be replanted after avulsion as it enhances
healing.
 Topical antibiotics has been reported to be more beneficial compared to systemic
antibiotics in avulsion cases. (Hinckfuss & Messer 2009).
The use of topical doxycycline significantly arrest inflammatory root resorption.
(Cvek et al. 1990).

Since inflammatory root resorption is one of the major challenges faced by clinicians during the
management of a replanted tooth, topical antibiotic administration might serve as a helpful means
to eliminate this undesirable complication.
The IADT guidelines indicate that topical application of tetracyclines (minocycline or
doxycycline, 1 mg per 20 ml of saline for 5 minutes) onto the root surface before reimplantation,
have a beneficial effect, increasing the chance of pulpal space revascularization and periodontal
healing in avulsed immature teeth with open apices (Andersson et al. 2012).

TYPES OF ANTIBIOTICS AND
RECOMMENDED DOSAGES IN
ENDODONTICS
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EFFECTIVE ANTIBIOTICS PRESCRIBED IN ENDODONTICS

Duration of antibiotic therapy
The duration of antibiotic use in endodontic infections has not been defined precisely.
Even though dental practitioners consider that bacterial infections require “a complete
course” of antibiotic therapy, a general tendency to administer an antibiotic for 3 to 7
days.
Since prolonged antibiotic usage destroys the commensal flora in the oral cavity and
other body sites, and terminates colonization resistance.
There is a common misconception that prolonged antibiotic administration is
necessary even after clinical remission of the infection in order to avoid rebound
infection.
Endodontic infections do not rebound when the source of periapical infection is
properly eradicated; which is complete debridement, irrigation and disinfection of an
infected root canal.
The only guide for determining the effectiveness of antibiotic therapy and local
endodontic intervention is the clinical improvement in the patient’s symptoms.
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When there is ample clinical evidence that the symptoms are resolving or resolved,
the antibiotic therapy should be ceased.
The key to obtaining a successful result in an endodontic infection is the chemo-
mechanical removal of the infecting agent from the root canal system as well as
drainage of pus.
 The indications for antibiotic administration should be considered very carefully and
only as an adjunct to endodontic treatment, which is the major and indispensable
procedure for obtaining the optimum outcome in lesions of endodontic origin.

ANTIBIOTIC PROPHYLAXIS FOR MEDICALLY
COMPROMISED PATIENTS
•The aim of antibiotic prophylaxis is to prevent local postoperative infections and
prevent metastatic spread of infection in susceptible individuals.
•The risk of adverse reactions to antibiotics and increasing development of drug-
resistant bacteria outweigh the benefits of prophylaxis for most patients.
•Antibiotics should only be given for prophylactic use in cases where the benefit has
been demonstrated to such use.
•Antibiotic prophylaxis may be considered for certain patient groups with impaired
immunologic function.
•There are only a few risk conditions in which antibiotic prophylaxis may be of benefit
to the patient in conjunction with dental procedures.
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Immuno-compromised patients
Individuals who are immunocompromised are less capable of battling infections
because of an immune response that is not properly functioning.
Causes of immunodeficiency can be acquired (such as leukaemia or HIV/AIDS),
chronic disease (such as end-stage renal disease and dialysis or uncontrolled diabetes),
medication (such as chemotherapy, radiation, steroids or immunosuppressive post-
transplant medications) or genetic (such as inherited genetic defects).
For most of these medical conditions, the treatment must be planned in close
collaboration with physicians.
For some medical conditions, the treatment must be preceded by a blood sample.
.

Complications of antibiotic therapy
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1. Direct toxicity
2. Hypersensitivity reaction
3. Drug resistance
4. Super infections
5. Nutritional deficiency
6. Masking of an infection

Toxicity
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a) Local irritancy
b) Systemic toxicity
Local irritancy
• This is exerted at the site of administration. Gastric irritation, pain
and abscess formation at the site of i.m. injection.
• Practically all antibiotics, especially erythromycin, tetracycline
certain cephalosporin and chloramphenicol are irritants.

Systemic toxicity:
• Almost all antibiotics produce dose related and predictable organ toxicities which
is measured by therapeutic index.
High therapeutic index- Low therapeutic index- Very Low therapeutic index-
doses up to many fold range
may be given without apparent
damage to host cells. These
include penicillins, some
cephalosporins and
erythromycin
doses have to be
individualized and toxicity
watched for:
Aminoglycosides : 8th cranial
nerve and kidney toxicity.
Tetracyclines : liver and
kidney damage.
Chloramphenicol : bone
marrow depression.
Use is highly restricted to
conditions where no
suitable alternative is
available.
Polymyxin B : neurological
and renal toxicity.
Vancomycin : hearing loss,
kidney damage.
Amphotericin B : kidney, bone
marrow and neurological
toxicity.

Hypersensitivity Reaction
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Practically all antibiotics are capable of causing
hypersensitivity reactions. These are unpredictable and
unrelated to dose. The whole range of reactions from
rashes to anaphylactic shock can be produced. The more
commonly involved antibiotics are-penicillins,
cephalosporins, sulfonamides, fluoroquinolones.

Drug resistance
• Natural resistance
• Acquired resistance
• Cross resistance
Acquired resistance is development of resistance by organism, which was sensitive
before due to the use of AMA over period of time.
Drug resistant organism can be broadly be of three type :
 Drug tolerant
 Drug destroying
 Drug impermeable
Acquisition of resistance to one antibiotic conferring resistance to another AMA, to
which the organism has not been exposed, is called cross resistance.

Super infections
Super infection refers to the appearance of a new infection as a result of
antibiotic therapy.
To minimize super infection
• Use specific (narrow spectrum antibiotic when ever possible
• Do not use antibiotic to treat trivial
• Do not unnecessary prolong antimicrobial therapy

Nutritional deficiency
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• Some of the B complex group of vitamins and vit K
synthesized by the intestinal flora is utilized by man.
Prolonged use of antimicrobials which alter this flora may
result in vitamin deficiencies.
• Neomycin causes morphological abnormalities in the
intestinal mucosa-steatorrhoea and malabsorption syndrome
can occur.

Masking of an infection
A short course of antibiotic may be sufficient to
treat one infection but briefly suppress another on
contacted concurrently. The other infection will be
masked initially only to manifest later in severe
form.

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TOPICALANTIBIOTIC USE
IN ENDODONTICS

Root canal treatment
Systemic antibiotics in some pulpal and periapical conditions, are ineffective and have
risk of adverse effects too this led to the use of locally applied antibiotics in root canal
treatment.
The endodontic infections are polymicrobial, tetracyclines, a group of broad-spectrum
antibiotics that are effective against a wide range of microorganisms.
However, microorganisms isolated from root canals have resistance against this group
of antibiotics and tetracyclines may promote fungal growth.
The use of topical antibiotics in root canal treatment has also been proposed to prevent
or reduce post-operative symptoms. However, antibiotics do not reduce the pain or
swelling arising from teeth.

LOCAL DRUG DELIVERY
• Grossman Polyantibiotic Paste
•Ledermix
•MTAD
•Septomixine Forte
•Tetraclean
•Triple Antibiotic Paste
•Odontopaste

Grossmans Poly antibiotic Paste
1st reported antibiotic for local use in endodontic treatment (1951).
It was known as PBSC( penicillin, bacitracin streptomycin, caprylate
sodium)..
The composition was ineffective against anaerobic species.
Penicillin Gram positive organisms
Bacitracin For penicillin- resistant strains
Streptomycin Gram – Negative organisms
Caprylate Sodium Yeasts

ANTIBIOTICS IN ENDODONTICS: 61
Ledermix Paste
Triamcinolone demeclocycline
•Anti-inflamatory action
•Concentration of 1%
•Antimicrobial action
•Concentration of 3.21%
•Effective in preventing inflammatory response in avulsed tooth
•Pain management

Septomixine Forte
Contains two antibiotics-
Neomycin
Polymyxin B Sulphate
Gram negative bacilli Neomycin
Gram positive bacteria Polymyxin B sulphate
Septomixine forte (Septodont) is a commercial product for intra
canal use. The effect against endodontic flora is not better than with
calcium hydroxide.

MTAD
BioPure MTAD, a mixture of doxycycline, citric acid, and a detergent. The important
properties of this irregant are:
antimicrobial activity,
smear layer- and pulp-dissolving capability,
effect on dentine and adhesion,
and biocompatibility.
Composition-
 3% doxycycline hyclate+4.25% citric acid+ 0.5% Polysorbate
Commercially available product: BioPure MTAD

ODONTOPASTE
Zinc oxide based endodontic dressing.
Composition
Clindamycin hydrochloride-5%
Triamcinolone acetonide- 1%
Calcium hydroxide-0.5%

Regenerative endodontic procedures
Regenerative Endodontic Procedures (REPs) is biologically based
procedures designed to replace damaged structures, including dentine
and root structures, as well as cells of the pulp–dentine complex.
In immature teeth with necrotic pulps and open apices, REPs promote
root development and apical closure.
Most REPs include minimal-to-no mechanical debridement, relying on
chemical debridement and on the use of intracanal medicaments to
achieve disinfection.
65

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Local Antibiotics used in regenerative endodontic
procedures:
The antibiotic mixture composed of ciprofloxacin, metronidazole, and minocycline
(100 μg/mL of each antibiotic, 300 μg/ mL of mixture) known as triple antibiotic paste
(TAP) or “3mix” is most widely used intracanal medicament in REP’s.
Metronidazole is a broad spectrum and strong antibacterial activity against anaerobic
cocci, as well as gram-negative and gram-positive bacilli.
Metronidazole permeates bacterial cell membranes, reaches the nuclei and binds to the
DNA, disrupting its helical structure, causing cell death.
Metronidazole has excellent activity against anaerobes isolated from odontogenic
abscesses.
The use of metronidazole has been advocated because of its low induction of bacterial
resistance.

67
Minocycline is a bacteriostatic and broad-spectrum antimicrobial. It is effective
against both gram-positive and gram-negative microorganisms, including most
spirochetes and many anaerobic and facultative bacteria.
Minocycline has been used in periodontal therapy, being available in many topical
forms.
Ciprofloxacin has very potent activity against gram-negative pathogens but its
activity is limited against gram-positive bacteria, and most anaerobic bacteria are
resistant to ciprofloxacin.
Consequently, ciprofloxacin is often combined with metronidazole in the treatment
of mixed infections.

Side effects of antibiotics used in regenerative endodontic
procedures
The use of antibiotics as intra canal dressings in REP may promote several side
effects.
A problem that often accompanies the intra-coronal use of TAP containing
minocycline is dentine discolouration.
Thibodeau & Trope (2007) suggested substituting minocycline for cefaclor in the tri-
antibiotic formula to avoid dentine discolouration, and Miller et al. (2012) confirmed
that the incorporation of cefaclor into TAP, instead of minocycline, avoided
discolouration.
The recent review and ESE position statement on revitalization procedures advocate
the use of calcium hydroxide instead of antibiotics to avoid discolouration.
68

The use of systemic antibiotics in Endodontics should be
limited to specific cases so as to avoid their over-
prescription.
Medically compromised patients are more susceptible to
complication arising from endodontic infections. Thus,
antibiotics should be considered in patients having systemic
diseases with compromised immunity and in patients with a
localized congenital or acquired altered defence capacity,
such as patients with infective endocarditis, prosthetic
cardiac valves, or with recent prosthetic joint replacement.
Amoxicillin (alone or together with clavulanic acid) is
recommended because of better absorption and lower risk of
side effects. In case of confirmed penicillin allergy,
lincosamides, such as clindamycin, are the drug of choice.
CONCLUSION

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medicaments containing clindamycin, doxycycline or demeclocycline. Australian Endodontic Journal 38, 124-8.
70

1. Peric M, Perkovic I, Romic M, et al. (2015) The pattern of antibiotic prescribing by dental practitioners in
Zagreb, Croatia. Central European Journal of Public Health 23, 107-13.
2. Poveda Roda R, Bagán JV, Sanchis Bielsa JM, Carbonell Pastor E (2007) Antibiotic use in dental practice.
A review. Medicina Oral, Patología Oral y Cirugía Bucal 12, E186-92.
3. Richey R, Wray D, Stokes T, (2008) Prophylaxis against infective endocarditis: summary of NICE
guidance. British Medical Journal 336, 770-1.
4. Roche Y, Yoshimori RN (1997) In vitro activity of spiramycin and metronidazole alone or in combination
against clinical isolates from odontogenic abscesses. Journal of Antimicrobial Chemotherapy 40, 353–77.
5. Rodríguez-Benítez S, Stambolsky C, Torres-Lagares D, Gutiérrez-Pérez JL, Segura-Egea JJ (2015) Pulp
revascularization of immature dog teeth with apical periodontitis using tri-antibiotic paste and platelet-rich
plasma: radiographic study. Journal of Endodontics 41, 1299-304.
6. Rodriguez-Núñez A, Cisneros-Cabello R, Velasco-Ortega E, Llamas-Carreras JM, Tórres-Lagares D,
Segura-Egea JJ (2009) Antibiotic use by members of the Spanish Endodontic Society. Journal of
Endodontics 35, 1198-203.
7. Sato I, Ando-Kurihara N, Kota K, et al. (1996) Sterilization of infected root-canal dentine by topical
application of a mixture of ciprofloxacin, metronidazole and minocycline in situ. International Endodontic
Journal 29, 118–24.
8. Schwartzberg LS (2006) Neutropenia: etiology and pathogenesis. Clinical Cornerstone 8, Suppl 5:S5-11.
9. Segura-Egea JJ, Velasco-Ortega E, Torres-Lagares D, Velasco-Ponferrada MC, Monsalve-Guil L, LLamas-
Carreras JM (2010) Pattern of antibiotic prescription in the management of endodontic infections among
Spanish oral surgeons. International Endodontic Journal 43, 342-50.
10. Seymour RA, Whitworth JM, Martin M (2003) Antibiotic prophylaxis for patients with joint prostheses -
still a dilemma for dental practitioners. British Dental Journal 194, 649-53.

7
2

DEFINITIONS
• BACTERIA: single-celled or noncellular spherical or spiral or rod-shaped organisms lacking
chlorophyll that reproduce by fission.
• GRAM POSITIVE- Thicker layers of peptidoglycans in the gram positive cell wall stains
purple in gram staining.
• GRAM NEGATIVE – Thin layers of peptidoglycans in gram negative cell wall appears
pink on gram staining.
By combining morphology and gram staining bacteria can be classified as:
• Gram positive cocci Gram negative cocci
• Gram positive bacilli Gram negative bacilli
• Aerobes :An organism (especially a bacterium) that requires air or free oxygen for life.
• Anaerobes: An organism (especially a bacterium) that does not require air or free oxygen to
live.

Gram-Negative Bacteria in endodontic infection:
• Gram-negative bacteria appear to be the most common microorganisms in primary
endodontic infections.
• These genera include:
• Dialister (e.g., D. invisus and D. pneumosintes),
• Treponema (e.g., T. denticola and T. socranskii ) ,
• Fusobacterium (e.g., F. nucleatum) ,
• Porphyromonas (e.g., P. endodontalis and P. gingivalis),
• Prevotella (e.g., P. intermedia, P. nigrescens, and P. tannerae), and
• Tannerella (e.g., T. forsythia).

Gram-Positive Bacteria
• Several gram-positive bacteria have also been frequently detected in the endodontic
mixed consortium, some of them in prevalence values as high as the most commonly
found gram-negative species.
• The genera of gram-positive bacteria often found in primary infections include
• Pseudoramibacter (e.g., P. alactolyticus),
• Filifactor (e.g., F. alocis),
• Micromonas (e.g., M. micros),
• Peptostreptococcus (e.g., P. anaerobius),
• Streptococcus (e.g., S. anginosus group),
• Actinomyces (e.g., A. israelii), Olsenella (e.g., O. uli), and
• Propionibacterium (e.g., P. propionicum and P. acnes ).

Ecology of the Endodontic Microbiota
• Bacterial colonization in root canal with necrotic pulp is because it
provide s a moist, warm, nutritious, and anaerobic environment, and it
lacks microcirculation and thus host defense.
• Thus the necrotic root canal is a rather fertile environment for bacterial
growth and colonization.
• The key ecologic factors that influence the composition of the microbiota
in the necrotic root canal are:
Oxygen Tension and Redox Potential
• In the very initial phases of the pulpal infectious process, facultative
bacteria predominate. After a few days or weeks, oxygen is depleted
within the root canal as a result of pulp necrosis and consumption by
facultative bacteria.
• An anaerobic milieu with consequent low redox potential develops, which
is highly conducive to the survival and growth of obligate anaerobic
bacteria.
• With the passage of time, anaerobic conditions become even more
pronounced, particularly in the apical third of the root canal, and as a
consequence, anaerobes will dominate the microbiota and out number
facultative bacteria.

Antibiotic resistance
77
•Antibiotic resistance : The ability of bacteria and other microorganism
to with stand to an antibiotic to which once they were sensitive
• Tolerance of microorganism to inhibitory action of antibiotics.
• Resistance to antibiotic is biological phenomenon that can be
accelerated by variety of factors including human practices.
• Resistance can be:
Drug tolerance
Drug destruction
Drug impermeability
Cross resistance

Factor affecting Antibiotic resistance
78

ANTIBIOTICS IN ENDODONTICS: A REVIEW 79

•MTAD is capable of:
Removing smear layer
Disinfecting the root canal
• Commercially available product: BioPure MTAD

ODONTOPASTE
Zinc oxide based endodontic dressing.
Composition
Clindamycin hydrochloride-5%
Triamcinolone acetonide- 1%
Calcium hydroxide-0.5%

Ledermix Paste
Triamcilone demecycoline
•Anti-inflamatory action
•Concentration of 1%
•Inhibits clastic cells (osteoclasts, cementoclast and
dentinoclast
•Antimicrobial action
•Concentration of 3.21%
•Effective in preventing inflammatory response in avulsed tooth
•Pain management

The Endodontic Microbiota
8
6
Table Microorganisms Detected in Root Canal–Treated Teeth Associated with Persistent Apical Periodontitis
Texa Frequency (%)
Enterococcus faecalis 77
Pseudoramibacter alactolyticus
Propionibacterium propionicum
Filifactor alocis
Dialister pneumosintes
Streptococcus spp.
Tannerella forsythia
Dialister invisus
Campylobacter rectus
Porphyromonas gingivalis
Treponema denticola
Fusobacterium nucleatum
Prevotella intermedia
Candida albicans
Campylobacter gracilis
Actinomyces radicidentis
Porphyromonas endodontalis
Micromonas micros
Synergistes oral clone BA121
Olsenella uli
55
50
48
46
23
23
14
14
14
14
10
10
9
5
5
5
5
5
5

Classification: based on chemical structure
8
7
1. Sulfonamides and related drugs: Sulfadiazine and others,
Sulfones-Dapsone (DDS).
2. Quinalones: Nalidixic acid, Norfloxacin, Ciprofloxacin etc.
3. β-Lactam antibiotics: Penicillins, Cephalosporins,
Monobactams, etc.
4. Tetracyclines: Oxytetracycline, Doxycyline, etc.
5. Nitrobenzene derivative: Chloramphenicol
6. Aminoglycosides: Streptomycin, Gentamicin, Neomycin, etc.
7. Macrolide antibiotics: Erythromycin, Clarithromycin,
Azithromycin, etc.
8. Lincosamide antibiotics: Lincomycin,Clindamycin.
9. Glycopeptide antibiotics: Vancomycin, etc.

8
8
10. Oxazolidinone: Linezolid.
11. Polypeptide antibiotics: Polymyxin-B, Bacitracin.
12. Nitrofuran derivatives: Nitrofurantoin, etc.
13. Nitroimidazoles: Metronidazole, Tinidazole etc.
14. Nicotinic acid derivatives: Isoniazid, Pyrazinamide, etc.
15. Polyene antibiotics. Nystatin, Amphotericin- B.
16. Azole derivatives: Miconazole, Clotrimazole,
Ketoconazole.
17. Others: Rifampin, Cycloserine, Ethambutol, Thiacetazone,
Griseofulvin.
Classification: based on chemical structure continued…

8
9
LIFE
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

9
0
• Mutulasim- describes the ecological interaction
between two or more species where each species
is benefited.
• Commensalism – long term biological interaction
in which one specimen gain benefit while other
species neither get harmed or benefited.
• Increase in cell size is growth and reproduction is
cell division.
• 9.8 minutes bacteria takes to be double..
Reproduction.
• Binary fission. Bacteria is asexual.

Combined use of antibiotic
9
1
• To achieve synergism
• To reduce severity and incidence of adverse effect
• To prevent emergence of resistance
• To broader the spectrum of drug

Selection of antibiotic
9
2
• Patient factor:
• Routes
• Drug factor

9
3
• EMPERICAL- BASED ON EXPERIENCE AND
OBSERVATION RATHER THAN SYSTEMATIC LOGIC.
• LOADING DOSE – IS INITIAL HIGHER DOSE OF A
DRUG THAT MAY BE GIVEN IN BEGINNING OF
COURSE OF TREATMENT ( BEFORE DROPING DOWN
ITS LOWER DOSE).
• LOADING DOSE IS GIVEN WHERE RAPID
ACHIEVEMNT OF THERAPEUTIC LEVEL IS DESIRED.
• LOADING DOSE DEPENDS ON:
• RATE OF ADMINISTRATION
• VOLUME OF DISTRIBUTION

9
4
• ACTINOMYCOSIS- RARE CHRONIC INFECTION
CAUSED BY SPECIES ACTIONOMYCETES.
CHARACTERISED BY ABSCESS FORMATION,
TISSUE FIBROSIS, SUPPURATIVE LESION AND
FISTULAS, PURULENT DISCHARGE CONTAINING
SULPHUR GRANULES.

WHY ENDODONTIC SURGERY
9
5
• USE IN DIAGNOSIS- PERSISTENT SYMPTOM BUT NO X- RAY
EVIDENCE.TOOTH MAY HAVE TINY FRACTURE OR CANAL CAN BE
DETECTED. ALLOWS TO EXAMINE ENTIRE ROOT OF TOOTH AND FIND
PROBLEM.
• SOMETIMES CALCIUM DEPOSIT MAKES CANAL TOO NARROW FOR
INSTRUMENT USED IN NON SURGICAL RCT TO REACH END OF THE ROOT. IF
YOUR TOOTH HAS THIS CALCIFICATION ENDODONTIST MAY PERFORM THIS
SURGERY TO CLEAN AND SEAL THE REMAINDER OF CANAL.
• IN FEW CASES AFTER RCT TOOTH MAY NOT HEAL OR BECOME INFECTED. A
TOOTH MAY BECOME PAINFUL OR DISEASED MONTH OR EVEN YEARS.
THEN SURGERY MAY HELP TOSAVE YOUR TOOTH.
• SURGERY MAY BE PERFORM TO TREAT DAMAGED TOOTH OR
SURROUNDING BONE.
• APICOECTOMY OR ROOT END RESECTION.
• WHEN INFLAMMATION OR INFECTION PERSIST IN BONY AREA AROUND
THE END OF YOUR TOOTH ENDODONTIST MAY PERFORM APICOECTOMY.

FLARE UP
96
• A FLARE UP MAY BE DEFINED AS OCCURENCE OF SEVERE PAIN
AND SWELLING FOLLOWING AN ENDODONTIC TREATMENT
REQUIRING AN UNSCHEDULED VISIT AND ACTIVE TREATMENT.
• FLARE UP IS A WELL KNOWN COMPLICATION THAT DISTURB
BOTH PATIENT AND DENTIST.
• CAUSATIVE FACTOR-
• MECHANICAL
• CHEMICAL
• MICROBIAL INJURY
• TO PULP OR PERIRADICULAR TISSUE.
• VARIOUS TREATMENT MODALITY : PREMEDICATION, DRAINAGE
ESTABLISHMENT, RELIEF OF OCCLUSION, INTRACANAL OR SYSTEMIC
MEDICATION

9
7
• COMPETITION- COMPETITION BETWEEN TWO
BACTERIAL POPULATIONS TENDS TO ELIMINATE
ONE POPULATION FROM THEIR COMMON
HABITAT.
• ANTAGONISM – THE INHIBITION OF ONE
BACTERIAL SPECIES BY ANOTHER.

TYPE OF BACTERIA
9
8
• STRICT ANAEROBE- FUNCTION AT LOW OXYGEN
REDUCTION POTENTIAL AND GROWING ONLY IN ABSENCE
OF OXYGEN.
• OBLIGATE ANAEROBES- LACKS THE ENZYME SUPEROXIDE
DISMUTANES AND CATALAYSE. SOME SPECIES OF
BACTERIA ARE MICROPHILIC, THEY CAN GROW IN
PRESENCE OF OXYGEN BUT THEY DERIVE MOST OF
ENERGY FROM ANAEROBIC ENERGY PATHWAY.
• FACULATATIVE ANAEROBE- CAN GROW IN PRESENCE OR
ABSENCE OF OXYGEN.
• OBLIGATE AEROBES- HAVE BOTH SUPEROXIDE
DISMUTANES AND CATALAYSE AND REQUIRE OXYGEN FOR
GROWTH.

SPIROCHETES
9
9
• T. DENTICOLA IS SPIROCHETES. GENUS
TREPONEMA
• FUNGI – CANDIDA ALBICAN

IRRIGANTS IN MICROBIAL CONTROL
1
0
0
• SODIUM HYPOCHLORITE
• COMBINATION OF SODIUM HYPOCHLORITE
WITH CHLORHEXIDINE
• CHLORHEXIDINE
• POVIDONE IODINE
• WORKS AGANST E. FAECALIS, P. MICROES, F.
NUCLEATUM, S. INTERMEDIUS.

1
0
1
• Therapeutic index in human = TD 50 / ED 50
• In animal = LD 50/ ED 50
• Therapeutic index is a quantitative measurement
of safety of drug.

102
Patients with locus minoris resistentiae
Locus minoris resistentiae refers to a body region more vulnerable than others, such
as internal organs or external body regions with a congenital or acquired altered
defense capacity.
Infective endocarditis, a bacterial infection of the heart valves or the endothelium of
the heart, is a typical case of locus minoris resistentiae.
Individuals with certain pre-existing heart defects are considered at risk for
developing endocarditis when a bacteraemia occurs.
Antibiotic prophylaxis has for a long time been considered as best practice for all
patients with complex congenital heart defects, prosthetic cardiac valve or a history
of infective endocarditis

According to the guidelines of the American Heart Association, individuals who are
at risk of developing infective endocarditis following an invasive dental procedure
benefit from antibiotic prophylaxis.
According to NICE (National Institute for Health and Clinical Excellence) Clinical
Guideline 64 (CG64), ‘Prophylaxis against infective endocarditis which is:
Antibiotic prophylaxis against infective endocarditis is not recommended routinely
for people undergoing dental procedures.
The addition of the word ‘routinely’ makes it clear that in individual cases antibiotic
prophylaxis may be appropriate.
The guidelines of the European Society of Cardiology (ESC) for the management
of infective endocarditis recommended antibiotic prophylaxis only for dental
procedures requiring manipulation of the gingival or periapical region of the teeth or
perforation of the oral mucosa, including scaling and root canal procedures.
103

In all treatment situations an overall medical assessment must be based on the
individual case and consideration of the risk of infection-related complications as well
as the risk of adverse drug reaction.
Prophylaxis may sometimes not be justified according to the medical condition in
connection with dental treatment, but can be justified when considering multiple
medical conditions and age, or when several risk factors predispose patients to
infections (such as poorly controlled or uncontrolled diabetes mellitus, malignancy,
chronic inflammatory disease, immunosuppressive disease or treatment with
immunosuppressive medication).
In cases of doubt over the proper management of patients prior to dental treatment, the
state and control of the disease of the patient should be discussed with a physician. The
choice of drug should reflect its clinical efficacy, as well as whether it is safe and has a
good spectrum.
104

The suggested prophylaxis regimen recommended by the AHA (Nishimura et al. 2008).

The amoxicillin, alone or in combination with clavulanic acid, is the preferred
prescribed antibiotic in endodontic infections with systemic effects .
Amoxicillin is a moderate-spectrum, bacteriolytic, β-lactam antibiotic; a synthetic
improvement upon the penicillin molecule.
It is better absorbed than penicillin and is able to resist damage from stomach acid so
less of an oral dose is wasted. Hence reduces the gastrointestinal side effects.
It also has a much broader spectrum against the gram-negative cell wall than
penicillin, and appropriate blood levels are retained for a slightly longer time.
However, amoxicillin is susceptible to degradation by β-lactamase-producing
bacteria, and often is given with clavulanic acid to increase its spectrum against
Staphylococcus aureus.
106

107
Due to its longer half-life and more sustained serum levels,
amoxicillin is taken 3 times a day and costs only slightly more than
penicillin.
The recommended oral dosage of amoxicillin with or without
clavulanic acid is 1000 mg loading dose followed by 500 mg every 8
hours.
The amoxicillin has a broader spectrum than is required for
endodontic needs and, therefore, its use in a healthy individual could
contribute to the global problem of antibiotic resistance.

108
 On the other hand, penicillin-induced diarrhea may even further reduce antibiotic
absorption, decreasing antibiotic levels in circulation and in the infected area.
Penicillin V is a narrow spectrum antibiotic for infections caused by aerobic Gram-
negative cocci, facultative and anaerobic microorganisms. It has selective toxicity and
exerts its antibacterial effect by the inhibition of cell wall production in bacteria.
However, penicillin is not well absorbed from the intestinal tract meaning that at least
70% of an oral dose is wasted, with diarrhoea as a frequent side effect. Penicillin is also
a short-acting medication, with half of the amount circulating being removed from the
body every half hour .

The majority of microorganisms have susceptibility to penicillin; so it is 1st choice
of drug for the adjunctive treatment of endodontic lesion.
However, amoxicillin has a wide spectrum against endodontic pathogens.
A loading dose of 1,000 mg of penicillin V should be administered orally followed
by 500 mg every four to six hours to achieve a steady serum level.
 Following debridement of the root canal system and drainage, significant
improvement should be seen within 48-72 hours.

However, if penicillin V therapy is ineffective, Clindamycin is a good alternative.
One disadvantage associated with penicillin use is the possibility of allergic reactions.
 In patients with a confirmed penicillin allergy history, the clinician can switch to
other antimicrobial agents such as clindamycin, metronidazole and clarithromycin or
azithromycin.
As a minimum the clinician should ask about the symptoms of allergy from the
patient.
Some patients may report intolerance symptoms, i.e. diarrhea or upset stomach, as an
allergy.

Clindamycin kills microorganisms by blocking their ribosomes.
It is effective against most gram-positive aerobes and both gram-positive and gram-
negative facultative bacteria and anaerobes.
It has effective distribution in most body tissues and has nearly same bone
concentration to that in the plasma.
The adult oral dosage is 600 mg loading dose followed by 300 mg every 6 h .
Clarithromycin and azithromycin are effective against a variety of aerobic and
anaerobic Gram-positive and Gram-negative bacteria.
Oral dosage for clarithromycin is a 500 mg loading dose followed by 250 mg every 12
h, the dosage for azithromycin is a loading dose of 500 mg followed by 250 mg once a
day.
111

112
Metronidazole is used either as an antiprotozoal agent or an antibiotic against
anaerobic bacteria, and has been suggested as a supplemental medication for
amoxicillin because of its excellent activity against anaerobes.
Because there are many bacteria resistant to metronidazole and it is not effective
against aerobic and facultative bacteria, it is generally used in combination with
penicillin or clindamycin.
Metronidazole used in combination with penicillin V or amoxicillin increased the
susceptibility to 93% and 99% of bacteria, respectively.
The adult oral dosage is 1000 mg loading dose followed by 500 mg every 6 h.

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