15. endodontic microbiology (1).pptNBBBBB

PRESENTED BY,
Dr. MONISHA TIWARI
Gui
ded by,
Dr. Rana K. Varghese, Prof. and Head
Dr. Rishidev Yadav, Reader
Dr. Subasish Behera, Reader
Dr. Minal Daga, Sr. Lecturer
Dr. Prashant Khetrapal, Sr. Lecturer
Dr. Deepak Agrawal, Sr. Lecturer

Introduction Introduction
Terminology Terminology
History History
Association of microbes in pulpal and periradiclar Association of microbes in pulpal and periradiclar
diseases diseases
Pathways of pulpal infection Pathways of pulpal infection
Micro-organisms associated with endodontic diseaseMicro-organisms associated with endodontic disease
Bacterial virulence factors Bacterial virulence factors
Periradicular responses to infections Periradicular responses to infections
Fascial space infections Fascial space infections

Management of abscesses and cellulitisManagement of abscesses and cellulitis
Antibiotics (antimicrobials ) for endodontic infections –Antibiotics (antimicrobials ) for endodontic infections –
pencillin pencillin
- amoxicillin - amoxicillin
- clarithromycin and - clarithromycin and
azithromycin azithromycin
-metronidazole-metronidazole
- clindamycin - clindamycin
Antibiotics for medically compromised patients Antibiotics for medically compromised patients
Microbial samples for laboratory support Microbial samples for laboratory support
Theory of focal infection –DÉJÀ VU?Theory of focal infection –DÉJÀ VU?
Association of oral and systemic disease.Association of oral and systemic disease.
Treatment of endodontic infections Treatment of endodontic infections
Summary and conclusion Summary and conclusion
References References

"Microbes were the first organisms to evolve on "Microbes were the first organisms to evolve on
the Earth and were its sole inhabitants for the Earth and were its sole inhabitants for
billions of years...only during the last 0.01 billions of years...only during the last 0.01
percent of Earth history have humans been percent of Earth history have humans been
around...bacteria may still dominate our around...bacteria may still dominate our
biosphere today in number of species, number biosphere today in number of species, number
of organisms, or total mass." (Bruce Jackosky, of organisms, or total mass." (Bruce Jackosky,
Planetary Review, July/August 1998)Planetary Review, July/August 1998)

Root canal morphology is a complex and contains Root canal morphology is a complex and contains
numerous ramifications and anatomical irregularities .numerous ramifications and anatomical irregularities .
The micro-organisms in the root canal not only The micro-organisms in the root canal not only
invades the anatomic irregularities in the root canal invades the anatomic irregularities in the root canal
system but also present in the dentinal tubules.system but also present in the dentinal tubules.
Persistent endodontic disease after root canal therapy Persistent endodontic disease after root canal therapy
may be caused by bacteria in the dentinal tubules .may be caused by bacteria in the dentinal tubules .
(Patricia Kho 2006 )(Patricia Kho 2006 )

Micro-organisms play an important role in the Micro-organisms play an important role in the
development of pulpal and periapical diseases development of pulpal and periapical diseases
and root canal instrumentation and fillings are and root canal instrumentation and fillings are
generally performed to eliminate the generally performed to eliminate the
organisms and prevent their recolonization in organisms and prevent their recolonization in
the root canal . However some bacteria can the root canal . However some bacteria can
survive and grow despite the treatment , an survive and grow despite the treatment , an
e.g. of such bacteria is E . Faecalis e.g. of such bacteria is E . Faecalis
species .This organisms is known to be species .This organisms is known to be
species commonly recovered from filled canals species commonly recovered from filled canals
. .
Seung -Eun Yang et al ,2006.Seung -Eun Yang et al ,2006.

Bacteria and their byproducts are considered to Bacteria and their byproducts are considered to
constitute the primary etiology of pulp necrosis constitute the primary etiology of pulp necrosis
and apical periodontitis . (luis chavez ,2007 ) .and apical periodontitis . (luis chavez ,2007 ) .
Primary root canal infection are Primary root canal infection are
polymicrobial ,typically dominated by obligate polymicrobial ,typically dominated by obligate
anaerobic bacteria. Matthias Zehnder(2006)anaerobic bacteria. Matthias Zehnder(2006)
The most frequently isolated micro-organisms The most frequently isolated micro-organisms
before root canal treatment include before root canal treatment include
-gram- negative anaerobic rods ,-gram- negative anaerobic rods ,
-gram positive anaerobic cocci,-gram positive anaerobic cocci,
- gram-positive anaerobic and facultative rods ,- gram-positive anaerobic and facultative rods ,
-lactobacillus species -lactobacillus species
-and gram positive facultative streptococcus -and gram positive facultative streptococcus
species . species .

Strictly anaerobic Strictly anaerobic
Microaerophilic Microaerophilic
Facultative anaerobic Facultative anaerobic
Obligate aerobes Obligate aerobes

The obligate anaerobes are easily eradicated The obligate anaerobes are easily eradicated
during root canal treatment . during root canal treatment .
On the other hand facultative bacteria such as On the other hand facultative bacteria such as
non mutans streptococci ,enterococci and non mutans streptococci ,enterococci and
lactobacilli once established are more likely to lactobacilli once established are more likely to
survive chemicomechanical instrumentation survive chemicomechanical instrumentation
and root canal medication.and root canal medication.

TerminologyTerminology
Colonization – it is the establishment of Colonization – it is the establishment of
bacteria or other organisms in a living bacteria or other organisms in a living
host .Colonization occurs if appropriate host .Colonization occurs if appropriate
biochemical and physical conditions are biochemical and physical conditions are
available for growth and inhibitory factors are available for growth and inhibitory factors are
inadequate to destroy the organisms . inadequate to destroy the organisms .
Pathogenicity – It is the capacity of organisms Pathogenicity – It is the capacity of organisms
to produce disease within a particular host .to produce disease within a particular host .
Virulence – expresses the degree of Virulence – expresses the degree of
pathogenicity in a host under defined pathogenicity in a host under defined
circumstances circumstances

Stages in development of Stages in development of
endodontic infectionendodontic infection
Microbial invasion Microbial invasion

colonization colonization

multiplication multiplication

pathogenic activity pathogenic activity

Micro-organisms have long being implicated in the Micro-organisms have long being implicated in the
pathogenesis of pulpal and peri-radicular disease . pathogenesis of pulpal and peri-radicular disease .
In 1894, Miller described bacteria in pulp In 1894, Miller described bacteria in pulp
chambers and root canals and also reported that chambers and root canals and also reported that
intraradicular bacteria were different from those in intraradicular bacteria were different from those in
the pulp chamber . the pulp chamber .
Onderdenk suggested the need for bacteriologic Onderdenk suggested the need for bacteriologic
examination of the root canal in 1901 . examination of the root canal in 1901 .

Shortly thereafter in 1910 Hunter made his Shortly thereafter in 1910 Hunter made his
historic address in Montreal in which he historic address in Montreal in which he
condemned the golden traps of sepsis ,the ill condemned the golden traps of sepsis ,the ill
fitting crowns and bridgework of his day that fitting crowns and bridgework of his day that
inexplicably resulted in the extraction of inexplicably resulted in the extraction of
countless numbers of treated pulpless teeth countless numbers of treated pulpless teeth
and the inception of focal infection theory .and the inception of focal infection theory .
La Roche and Coolidge suggested that La Roche and Coolidge suggested that
bacteriologic examination be used in treating bacteriologic examination be used in treating
the root canal .the root canal .

Bacteriologic studies by Haden in 1928 as well Bacteriologic studies by Haden in 1928 as well
as by Burket in 1937 examined the growth as by Burket in 1937 examined the growth
percentages of bacteria ,probably aerobes , in percentages of bacteria ,probably aerobes , in
cultures of vital and pulpless teeth .cultures of vital and pulpless teeth .
Another study was published in 1936 by Fish Another study was published in 1936 by Fish
and MacLean who demonstrated that the pulp and MacLean who demonstrated that the pulp
and periapical tissues of vital healthy teeth are and periapical tissues of vital healthy teeth are
invariably free of evidence of micro-organisms invariably free of evidence of micro-organisms
when examined histologically and that it when examined histologically and that it
practically impossible to extract a tooth practically impossible to extract a tooth
aseptically unless the crevicular gingiva is aseptically unless the crevicular gingiva is
cauterized first . cauterized first .

In 1935 ,Okell and Elliot reported a transient In 1935 ,Okell and Elliot reported a transient
bacteremia following extraction and in bacteremia following extraction and in
1936 ,Round and his associates showed that a 1936 ,Round and his associates showed that a
transient bacteremia occurred when a patient with transient bacteremia occurred when a patient with
marked periodontal condition simply chewed marked periodontal condition simply chewed
candy . candy .
Appleton 1933,suggested that without bacteria no Appleton 1933,suggested that without bacteria no
need would exist for endodontic treatment . need would exist for endodontic treatment .
Since 1901, the question of validity of culturing Since 1901, the question of validity of culturing
remains and the controversy continues . remains and the controversy continues .
Many have translated their rejection of Many have translated their rejection of
bacteriologic examination into a rejection of any bacteriologic examination into a rejection of any
serious relationship between microbiology and serious relationship between microbiology and
endodontic treatment . endodontic treatment .

Naidorf wrote the fatuous preoccupation with Naidorf wrote the fatuous preoccupation with
culturing technique has unfortunately diverted culturing technique has unfortunately diverted
attention away from the basic biologic attention away from the basic biologic
principles of host – parasite relationship . principles of host – parasite relationship .
It was not until 1966, however that bacteria It was not until 1966, however that bacteria
were conclusively shown to cause pulpal were conclusively shown to cause pulpal
necrosis and periradicular inflammation when necrosis and periradicular inflammation when
Kakehashi et al exposed pulps in gnotobiotic Kakehashi et al exposed pulps in gnotobiotic
and conventional rats for 42 days .and conventional rats for 42 days .

In 1966, Moller described a technique which In 1966, Moller described a technique which
allowed samples of bacteria to be maintained allowed samples of bacteria to be maintained
and subsequently cultured in the laboratory . and subsequently cultured in the laboratory .
The advent of this technique led to subsequent The advent of this technique led to subsequent
identification of anaerobic bacteria involved in identification of anaerobic bacteria involved in
endodontic infection . endodontic infection .

Micro-organisms reported in Micro-organisms reported in
human root canals prior to human root canals prior to
19691969
Streptococci – alphaStreptococci – alpha
- - ββ
- gamma - gamma
-enterococci-enterococci
- anaerobic - anaerobic
Staphylococcus –aureus Staphylococcus –aureus
- albius- albius
PneumococciPneumococci
LactobacilliLactobacilli
Bacillus substilisBacillus substilis
Diptheroids Diptheroids

NeisseriaNeisseria
E.ColiE.Coli
PseudomonasPseudomonas
MoniliaMonilia

A simple classification of A simple classification of
gram positive bacteria gram positive bacteria
Cocci – aerobes – clusters –staphylococcusCocci – aerobes – clusters –staphylococcus
(s.aureus, s epidermidis)(s.aureus, s epidermidis)
- chain/pairs-streptococcus- chain/pairs-streptococcus
(s.pneumoniae, s.pyogens,s.virdian group )(s.pneumoniae, s.pyogens,s.virdian group )
-anaerobes – chain/clusters – -anaerobes – chain/clusters –
peptostreptococcus (p.anaerbius ) peptostreptococcus (p.anaerbius )

Bacilli – aerobes –sporing –bacillus- b. Bacilli – aerobes –sporing –bacillus- b.
anthracis)anthracis)
- non- sporing-- non- sporing-
corynebacterium (c. diptherium ), corynebacterium (c. diptherium ),
lactobacillus – l. acidophilus, nocardia –n. lactobacillus – l. acidophilus, nocardia –n.
asteroides .asteroides .

Anaerobic –sporing – clostridium (c. Anaerobic –sporing – clostridium (c.
tetani ,c.perfringens )tetani ,c.perfringens )
-non-sporing – -non-sporing –
propionibacterium (p.acnes), propionibacterium (p.acnes),
actinomyces –(A israelii.)actinomyces –(A israelii.)

A simple classification of A simple classification of
gram negative bacteria gram negative bacteria
Cocci- aerobes – neisseria Cocci- aerobes – neisseria
(N .meningitidis ,N.gonorrhoea)(N .meningitidis ,N.gonorrhoea)
-anaerobic – veillonella –(V. parvula )-anaerobic – veillonella –(V. parvula )
Bacilli –Aerobes –pseudomonas (P.aeruginosa )Bacilli –Aerobes –pseudomonas (P.aeruginosa )

Aerobes/facultative anaerobes – hemophilis Aerobes/facultative anaerobes – hemophilis
(H. influenza, Brucella (B. abortus ), Bordetella (B. (H. influenza, Brucella (B. abortus ), Bordetella (B.
pertusis ) ,Pasteurella (P.mutocida ), Yersinia pertusis ) ,Pasteurella (P.mutocida ), Yersinia
(Y.pestis ),E.Coli, Klesbsiella aerogenes, (Y.pestis ),E.Coli, Klesbsiella aerogenes,
Salmonella typhi , Shigella sonnei .Salmonella typhi , Shigella sonnei .

Anaerobes – bacteroides (B . Fragilis ) Anaerobes – bacteroides (B . Fragilis )
-porphyromonas -porphyromonas
(P.Gingivalis), Prevotella –P.intermedia .(P.Gingivalis), Prevotella –P.intermedia .
Spirochaetes – aerobes – leptospira Spirochaetes – aerobes – leptospira
-anaerobes–treponema -anaerobes–treponema

Microbiology of Microbiology of
endodontic infections endodontic infections
Bacteria may not only reside in the main canal , Bacteria may not only reside in the main canal ,
but they may invade the dentinal tubules making but they may invade the dentinal tubules making
them act as a reservoir for future dental and them act as a reservoir for future dental and
systemic infections . systemic infections .
Porphyromonas gingivalis , tannerella forsythensis Porphyromonas gingivalis , tannerella forsythensis
and fusobacterium nucleatum are associated with and fusobacterium nucleatum are associated with
extraradicular biofilm formation and refractory extraradicular biofilm formation and refractory
periapical chronic periodontitis . periapical chronic periodontitis .
The presence of T . Forsythensis ,P. gingivalis and The presence of T . Forsythensis ,P. gingivalis and
treponema denticola was demonstrated in root treponema denticola was demonstrated in root
canal samples collected from patients with carious canal samples collected from patients with carious
lesions , necrotic pulp and radiographic evidence lesions , necrotic pulp and radiographic evidence
of periradicular bone loss . of periradicular bone loss .

T .Denticola was highly associated with T .Denticola was highly associated with
symptomatic endodontic infections and symptomatic endodontic infections and
periapical bone resorption , whereas E . periapical bone resorption , whereas E .
Faecalis was associated with asymptomatic Faecalis was associated with asymptomatic
chronic periapical periodontitis and secondary chronic periapical periodontitis and secondary
endodontic infections in endodontic failures . endodontic infections in endodontic failures .
Black pigmented bacteria have been isolated Black pigmented bacteria have been isolated
with acute abscess of dental origin ,suggesting with acute abscess of dental origin ,suggesting
an active role in the pathogenesis of acute an active role in the pathogenesis of acute
symptoms . symptoms .

Microbiology of Microbiology of
periodontal pathogens periodontal pathogens
The periodontal infection is caused by micro-The periodontal infection is caused by micro-
organisms colonizing the tooth surface at the organisms colonizing the tooth surface at the
supra or subgingival level .supra or subgingival level .
Actinobacillus Actinobacillus
actinomycetemcomitans,P .gingivalis ,T .forsynthactinomycetemcomitans,P .gingivalis ,T .forsynth
ensis , P.Intermedia,F .nucleatum,campylobacter ensis , P.Intermedia,F .nucleatum,campylobacter
rectus , Eikenella corrodens , rectus , Eikenella corrodens ,
Peptostreptococcus micros and Eubacterium are Peptostreptococcus micros and Eubacterium are
the best studied periodontal pathogens . the best studied periodontal pathogens .

Relationship between Incidence of Black-pigmented Relationship between Incidence of Black-pigmented
Anaerobic Rods and Clinical Symptoms on Traumatic Anaerobic Rods and Clinical Symptoms on Traumatic
Non-vital Teeth IINO FUMIAKI et al Non-vital Teeth IINO FUMIAKI et al
Japanese Journal of Conservative Dentistry(2003)
Gram-negative anaerobes, especially black-Gram-negative anaerobes, especially black-
pigmented rods (BPRs), such as genera pigmented rods (BPRs), such as genera
Porphyromonas and Prevotella are well known as Porphyromonas and Prevotella are well known as
the predominant bacteria isolated from open infected the predominant bacteria isolated from open infected
root canals, and the same is true regarding root canals, and the same is true regarding
periodontal disease. Also, these gram-negative periodontal disease. Also, these gram-negative
anaerobes are separated significantly from anaerobes are separated significantly from
periodontal pockets. However, there is little periodontal pockets. However, there is little
information on the incidence of BPRs in closed information on the incidence of BPRs in closed
infected root canals. infected root canals.
his study investigated the incidence and source of his study investigated the incidence and source of
BPRs in infected root canals caused by trauma. BPRs in infected root canals caused by trauma.

These results suggested that some These results suggested that some
clinical symptoms were associated with clinical symptoms were associated with
the occurrence of BPRs. Prevotella the occurrence of BPRs. Prevotella
nigrescens were isolated from the nigrescens were isolated from the
gingival sulcus or periodontal pocket of gingival sulcus or periodontal pocket of
the teeth, thus isolating Prevotella the teeth, thus isolating Prevotella
nigrescens from the root... nigrescens from the root...

Association of specific bacteria with some endodontic Association of specific bacteria with some endodontic
signs and symptomssigns and symptoms
Pain and prevotella / peptostreptococcus Pain and prevotella / peptostreptococcus
speciesspecies
- peptostreptococcus species / - peptostreptococcus species /
prevotella melaninogenica prevotella melaninogenica
-peptostreptococcus micros/ prevotella -peptostreptococcus micros/ prevotella
melaninogenica melaninogenica

Tenderness on percussionTenderness on percussion
– –peptococcus peptococcus
-peptostreptococcus-peptostreptococcus
-Porphyromonas -Porphyromonas
-Eubacterium -Eubacterium
-Bacteroides -Bacteroides

Odor in infected root canal Odor in infected root canal
-porphyromonas -porphyromonas
Eubacterium Eubacterium

Swelling – peptostreptococcus Swelling – peptostreptococcus
micros/prevotella species micros/prevotella species

Wet canal and prevotella species/ Wet canal and prevotella species/
eubacterium species eubacterium species
Peptostreptococcus/ eubacterium Peptostreptococcus/ eubacterium
species species

Relationship between clinical symptoms and Relationship between clinical symptoms and
enzyme-producing bacteria isolated from infected enzyme-producing bacteria isolated from infected
root canalsroot canals. . Hashioka K et al , J Endo ,20(2),1994Hashioka K et al , J Endo ,20(2),1994
The object of this study was to determine the The object of this study was to determine the
correlation between clinical symptoms and the correlation between clinical symptoms and the
activity of enzymes such as collagenase, activity of enzymes such as collagenase,
chondroitinase, and hyaluronidase produced by chondroitinase, and hyaluronidase produced by
bacteria isolated from infected root canals. bacteria isolated from infected root canals.
Bacteria releasing these enzymes were Bacteria releasing these enzymes were
associated with subacute clinical symptoms associated with subacute clinical symptoms
involving percussion pain . involving percussion pain .
The frequency of bacteria producing collagenase The frequency of bacteria producing collagenase
was higher in isolates from root canals with a was higher in isolates from root canals with a
radiolucent area over 5 mm in diameter than in radiolucent area over 5 mm in diameter than in
those from canals having a radiolucent area less those from canals having a radiolucent area less
than 5 mm in diameter. than 5 mm in diameter.

Quantification of endotoxins in necrotic root canals from Quantification of endotoxins in necrotic root canals from
symptomatic and asymptomatic teeth.symptomatic and asymptomatic teeth.
Rogerio C Jacinto, J Med Microbiol 54 (2005 ).Rogerio C Jacinto, J Med Microbiol 54 (2005 ).
The purpose of this investigation was to quantify the The purpose of this investigation was to quantify the
concentration of endotoxin in necrotic root canals concentration of endotoxin in necrotic root canals
and investigate the possible relationship between and investigate the possible relationship between
the concentration of endotoxin and endodontic signs the concentration of endotoxin and endodontic signs
and symptoms. and symptoms.
Asymptomatic cases generally had lower levels of Asymptomatic cases generally had lower levels of
endotoxin (i.e. a negative association). A positive endotoxin (i.e. a negative association). A positive
association was found between endotoxin and association was found between endotoxin and
symptomatic cases (e.g. spontaneous pain, symptomatic cases (e.g. spontaneous pain,
tenderness to percussion, pain on palpation, tenderness to percussion, pain on palpation,
swelling and purulent exudates). This study showed swelling and purulent exudates). This study showed
that endotoxin is present in high concentrations in that endotoxin is present in high concentrations in
root canals of symptomatic teeth. root canals of symptomatic teeth.

There was a positive correlation between the There was a positive correlation between the
concentration of endotoxin in the root canal concentration of endotoxin in the root canal
and the presence of endodontic signs and and the presence of endodontic signs and
symptoms. symptoms.

Association between Bacteroides forsythus in the Association between Bacteroides forsythus in the
infected root canals and clinical symptoms of chronic infected root canals and clinical symptoms of chronic
apical periodontitis]apical periodontitis] Huang DM Sichuan Da Xue Xue Huang DM Sichuan Da Xue Xue
Bao Yi Xue Ban. 2005 Jan;36(1):46-9Bao Yi Xue Ban. 2005 Jan;36(1):46-9
To investigate the distribution of Bacteroides To investigate the distribution of Bacteroides
forsythus in root canals with chronic apical forsythus in root canals with chronic apical
periodontitis and to determine its associations with periodontitis and to determine its associations with
clinical symptoms. clinical symptoms.
Significant positive associations were observed Significant positive associations were observed
between B. forsythus in infected root canals and between B. forsythus in infected root canals and
the spontaneous pain, percussion pain, and the spontaneous pain, percussion pain, and
swelling of apical periodontitis, respectively .swelling of apical periodontitis, respectively .
There was no significant association between B. There was no significant association between B.
forsythus and sinus tract of apical periodontitis .forsythus and sinus tract of apical periodontitis .

Naidrof compiled a list of generalizations Naidrof compiled a list of generalizations
regarding organisms isolated from root regarding organisms isolated from root
canals as followscanals as follows
Mixed infections are more common than single Mixed infections are more common than single
organism isolates .organism isolates .
The wide variety of organisms found in the root The wide variety of organisms found in the root
canals by different investigators can be partially canals by different investigators can be partially
related to the principal interests and culture related to the principal interests and culture
techniques of these investigators .techniques of these investigators .
The invasion of dentin from the pulp has been The invasion of dentin from the pulp has been
described ,but the types of organisms, growth rate described ,but the types of organisms, growth rate
and viability are poorly understood . and viability are poorly understood .

Pulp isolates are similar to oral flora with gram Pulp isolates are similar to oral flora with gram
positive cocci predominating . positive cocci predominating .
Approximately 25% of the isolated organisms Approximately 25% of the isolated organisms
are anaerobes .are anaerobes .
Organisms associated with flare –ups do not Organisms associated with flare –ups do not
differ from asymptomatic canal isolates . differ from asymptomatic canal isolates .
Organisms cultured from infected canals Organisms cultured from infected canals
elaborate a wide variety of invasive elaborate a wide variety of invasive
enzymes ,but this capability cannot always be enzymes ,but this capability cannot always be
equated with pathogenecity . equated with pathogenecity .
The present practice of treating the obvious The present practice of treating the obvious
source of infection , the root canal and not the source of infection , the root canal and not the
periapical tissue conforms to the finding of periapical tissue conforms to the finding of
Hedman as well as those of Melville and Birch Hedman as well as those of Melville and Birch
(1967). (1967).

Dental caries Dental caries
Dentinal tubules Dentinal tubules
Direct exposure of the pulp from restorative Direct exposure of the pulp from restorative
procedures, a traumatic injury or an procedures, a traumatic injury or an
anomalous tooth development .anomalous tooth development .
Through portals at the apex of rootThrough portals at the apex of root
Through lateral,accessory or furcation canals .Through lateral,accessory or furcation canals .
Anachoresis Anachoresis

Invasion of dentinal tubules by oral bacteria. Invasion of dentinal tubules by oral bacteria.
Love RM, Jenkinson HF.Love RM, Jenkinson HF.
Crit Rev Oral Biol Med. 2002;13(2):171-83. Crit Rev Oral Biol Med. 2002;13(2):171-83.
Bacterial invasion of dentinal tubules Bacterial invasion of dentinal tubules
commonly occurs when dentin is exposed commonly occurs when dentin is exposed
following a breach in the integrity of the following a breach in the integrity of the
overlying enamel or cementum. Bacterial overlying enamel or cementum. Bacterial
products diffuse through the dentinal tubule products diffuse through the dentinal tubule
toward the pulp and evoke inflammatory toward the pulp and evoke inflammatory
changes in the pulpo -dentin complex. These changes in the pulpo -dentin complex. These
may eliminate the bacterial insult and block the may eliminate the bacterial insult and block the
route of infection. route of infection.

Unchecked, invasion results in pulpitis and pulp Unchecked, invasion results in pulpitis and pulp
necrosis, infection of the root canal system, and necrosis, infection of the root canal system, and
periapical disease. While several hundred periapical disease. While several hundred
bacterial species are known to inhabit the oral bacterial species are known to inhabit the oral
cavity, a relatively small and select group of cavity, a relatively small and select group of
bacteria is involved in the invasion of dentinal bacteria is involved in the invasion of dentinal
tubules and subsequent infection of the root canal tubules and subsequent infection of the root canal
space. space.
 Gram-positive organisms dominate the tubule Gram-positive organisms dominate the tubule
microflora in both carious and non-carious dentin. microflora in both carious and non-carious dentin.
The relatively high numbers of obligate anaerobes The relatively high numbers of obligate anaerobes
present-such as Eubacterium spp., present-such as Eubacterium spp.,
Propionibacterium spp., Bifidobacterium spp., Propionibacterium spp., Bifidobacterium spp.,
Peptostreptococcus micros, and Veillonella spp.-Peptostreptococcus micros, and Veillonella spp.-
suggest that the environment favors growth of suggest that the environment favors growth of
these bacteria. these bacteria.

Gram-negative obligate anaerobic rods, e.g., Gram-negative obligate anaerobic rods, e.g.,
Porphyromonas spp., are less frequently Porphyromonas spp., are less frequently
recovered. Streptococci are among the most recovered. Streptococci are among the most
commonly identified bacteria that invade dentin. commonly identified bacteria that invade dentin.
Recent evidence suggests that streptococci may Recent evidence suggests that streptococci may
recognize components present within dentinal recognize components present within dentinal
tubules, such as collagen type I, which stimulate tubules, such as collagen type I, which stimulate
bacterial adhesion and intra-tubular growth. bacterial adhesion and intra-tubular growth.
Specific interactions of other oral bacteria with Specific interactions of other oral bacteria with
invading streptococci may then facilitate the invading streptococci may then facilitate the
invasion of dentin by select bacterial groupings. invasion of dentin by select bacterial groupings.
An understanding the mechanisms involved in An understanding the mechanisms involved in
dentinal tubule invasion by bacteria should allow dentinal tubule invasion by bacteria should allow
for the development of new control strategies, for the development of new control strategies,
such as inhibitory compounds incorporated into such as inhibitory compounds incorporated into
oral health care products or dental materials, oral health care products or dental materials,
which would assist in the practice of endodontics.which would assist in the practice of endodontics.

Observation of bacteria and fungi in infected root Observation of bacteria and fungi in infected root
canals and dentinal tubules by SEMcanals and dentinal tubules by SEM
B. H. Sen et al , dental traumatology , volume 11, B. H. Sen et al , dental traumatology , volume 11,
issue 1 ,2007issue 1 ,2007
The aim of this study was to observe the root The aim of this study was to observe the root
canal flora and possible penetration of canal flora and possible penetration of
microorganisms into dentinal tubules in teeth with microorganisms into dentinal tubules in teeth with
necrotic pulps. Ten infected maxillary and necrotic pulps. Ten infected maxillary and
mandibular molars with periapical lesions were mandibular molars with periapical lesions were
extracted and fixed in 2.5% phosphate-buffered extracted and fixed in 2.5% phosphate-buffered
glutaraldehyde solution for nine days. After glutaraldehyde solution for nine days. After
separation from the crowns, longitudinal grooves separation from the crowns, longitudinal grooves
were cut in the roots, and they were split into two were cut in the roots, and they were split into two
halves. The specimens were prepared for SEM. halves. The specimens were prepared for SEM.
The root canals and the dentinal tubules of the The root canals and the dentinal tubules of the
fractured dentin were scanned systematically fractured dentin were scanned systematically
from the cervical to the apical area of the root. from the cervical to the apical area of the root.

Cocci and rods were seen in 6 Cocci and rods were seen in 6
specimens. Penetration of bacteria into specimens. Penetration of bacteria into
the dentinal tubules ranged from 10 to the dentinal tubules ranged from 10 to
150 μm. In 4 specimens, the root canals 150 μm. In 4 specimens, the root canals
were heavily invaded by yeasts. The were heavily invaded by yeasts. The
antimicrobial effect of routinely used antimicrobial effect of routinely used
endodontic disinfectants also on yeasts endodontic disinfectants also on yeasts
may be considered in persistent root may be considered in persistent root
canal infections.canal infections.

The effect of tissue molecules on bacterial The effect of tissue molecules on bacterial
invasion of dentine. Love RM.invasion of dentine. Love RM.
Oral Microbiol Immunol. 2002 Feb;17(1):32-Oral Microbiol Immunol. 2002 Feb;17(1):32-
7. 7.
Bacterial invasion of dentinal tubules is a critical Bacterial invasion of dentinal tubules is a critical
step in the pathogenesis of dental caries and pulp step in the pathogenesis of dental caries and pulp
and periapical disease. The purpose of this study and periapical disease. The purpose of this study
was to determine the effect some molecules was to determine the effect some molecules
commonly found in saliva and dentinal tubule fluid commonly found in saliva and dentinal tubule fluid
may have on the bacterial invasion of dentine. may have on the bacterial invasion of dentine.

The results showed that invasion of Streptococcus The results showed that invasion of Streptococcus
gordonii or Enterococcus faecalis cells was gordonii or Enterococcus faecalis cells was
inhibited when the bacterial cells were in solution inhibited when the bacterial cells were in solution
with mucin, immunoglobulin G (IgG) and serum, with mucin, immunoglobulin G (IgG) and serum,
and this was related to bacterial cell aggregation, and this was related to bacterial cell aggregation,
as a result of interaction with agglutinins, and/or as a result of interaction with agglutinins, and/or
inhibition of collagen binding. inhibition of collagen binding.
When dentine was soaked in growth media When dentine was soaked in growth media
containing fibrinogen, IgG, albumin or serum prior containing fibrinogen, IgG, albumin or serum prior
to inoculation, bacterial invasion was inhibited. It is to inoculation, bacterial invasion was inhibited. It is
suggested that this may be due to reduced dentine suggested that this may be due to reduced dentine
permeability as a consequence of the deposition permeability as a consequence of the deposition
of the compounds within dentinal tubules.of the compounds within dentinal tubules.

Bacterial adhesins --their role in tubule invasion Bacterial adhesins --their role in tubule invasion
and endodontic disease. Love RM.and endodontic disease. Love RM.
Aust Endod J. 2002 Apr;28(1):25-8. Aust Endod J. 2002 Apr;28(1):25-8.
Bacterial invasion of dentinal tubules is critical to Bacterial invasion of dentinal tubules is critical to
the progression of dental caries and the the progression of dental caries and the
development of pulp and periapical disease, and development of pulp and periapical disease, and
may also influence the progression of periodontal may also influence the progression of periodontal
disease. disease.
Recent work has demonstrated that bacterial Recent work has demonstrated that bacterial
interactions with dentine, and salivary and tissue interactions with dentine, and salivary and tissue
molecules influence invasion. molecules influence invasion.

Salivary molecules such as mucin and Salivary molecules such as mucin and
immunoglobulin G (IgG) co-aggregate with immunoglobulin G (IgG) co-aggregate with
bacterial cells, which inhibits dentine invasion, bacterial cells, which inhibits dentine invasion,
while deposition of dentinal tubule fluid molecules while deposition of dentinal tubule fluid molecules
e.g. albumin, IgG, or fibrinogen within dentinal e.g. albumin, IgG, or fibrinogen within dentinal
tubules also inhibits invasion. tubules also inhibits invasion.
. Dentine invasion by streptococci has been . Dentine invasion by streptococci has been
shown to be associated with a bacterial growth shown to be associated with a bacterial growth
response and adhesion to unmineralized response and adhesion to unmineralized
collagen, which are mediated by streptococcal collagen, which are mediated by streptococcal
cell-surface antigen I/II polypeptides. These cell-surface antigen I/II polypeptides. These
adhesins possess diverse binding properties adhesins possess diverse binding properties
including binding to salivary glycoprotein, other including binding to salivary glycoprotein, other
bacteria, and to collagen. bacteria, and to collagen.

Additionally, some antigen I/II Additionally, some antigen I/II
polypeptides facilitate species-specific polypeptides facilitate species-specific
co-invasion between streptococci and co-invasion between streptococci and
obligate anaerobes that lack the ability to obligate anaerobes that lack the ability to
invade by themselves. An understanding invade by themselves. An understanding
of the mechanisms involved in bacterial of the mechanisms involved in bacterial
invasion of dentine should allow invasion of dentine should allow
development of new control strategiesdevelopment of new control strategies..

Dentinal tubule invasion and adherence by Dentinal tubule invasion and adherence by
Enterococcus faecalis. Chivatxaranukul PEnterococcus faecalis. Chivatxaranukul P
Int Endod J. 2008 Oct;41(10):873-82Int Endod J. 2008 Oct;41(10):873-82
 To investigate dentinal tubule invasion and the To investigate dentinal tubule invasion and the
predilection of Enterococcus faecalis for dentinal tubule predilection of Enterococcus faecalis for dentinal tubule
walls. walls.
. RESULTS: The strain of E. faecalis used in this study . RESULTS: The strain of E. faecalis used in this study
showed moderate to heavy tubule invasion after 8 showed moderate to heavy tubule invasion after 8
weeks. In the adhesion studies,significantly more weeks. In the adhesion studies,significantly more
bacteria adhered to fractured Orthodentin than to bacteria adhered to fractured Orthodentin than to
dentinal tubule walls . With respect to the tubule wall, dentinal tubule walls . With respect to the tubule wall,
adherence was greater in inner versus outer dentine and adherence was greater in inner versus outer dentine and
greater when bacterial adhesion was tested in chemically greater when bacterial adhesion was tested in chemically
defined medium than in phosphate-buffered saline.defined medium than in phosphate-buffered saline.

In 1890 WD Miller , the father of oral In 1890 WD Miller , the father of oral
microbiology was the first investigator to microbiology was the first investigator to
associate the presence of bacteria with pulpal associate the presence of bacteria with pulpal
disease.disease.
A classic study published by Kakehashi et al A classic study published by Kakehashi et al
proved the bacteria were the cause of pulpal proved the bacteria were the cause of pulpal
and periradicular disease.and periradicular disease.
Before 1970 only few strains of anaerobic Before 1970 only few strains of anaerobic
bacteria were isolated because of inadequate bacteria were isolated because of inadequate
culturing methods . culturing methods .

Before 1970 only few strains of anaerobic Before 1970 only few strains of anaerobic
bacteria were isolated because of bacteria were isolated because of
inadequate culturing methods . inadequate culturing methods .
Currently the vast majority of the bacteria Currently the vast majority of the bacteria
isolated from an endodontic infection are isolated from an endodontic infection are
anaerobic .anaerobic .
Few organisms have been found to be Few organisms have been found to be
cultivated from endodontic infections . cultivated from endodontic infections .
 this is relatively small, restricted group of this is relatively small, restricted group of
organisms compared with normal oral flora organisms compared with normal oral flora
which contains more than 500 species of which contains more than 500 species of
cultivable bacteria . cultivable bacteria .

Other species isolated in low incidence included Other species isolated in low incidence included
::
Porphyromonas gingivalis Porphyromonas gingivalis
Bacteriodes ureolyticus .Bacteriodes ureolyticus .
Lactobacillus minutus Lactobacillus minutus
Lactobacillus catenaformeLactobacillus catenaforme
E.faecalis E.faecalis
Peptostreptococcus prevottiPeptostreptococcus prevotti
Eienella corrodens Eienella corrodens
And enterobacter agglomerans And enterobacter agglomerans

Association of specific bacteria with some endodontic signs and Association of specific bacteria with some endodontic signs and
symptomssymptoms
. International Endodontic Journal. International Endodontic Journal
Volume 27 Issue 6Volume 27 Issue 6,
Pages 291 - 298
,
Pages 291 - 298
Published Online: 25
Sep 2007 ,B. P. F. A. GOMES et al
Published Online: 25
Sep 2007 ,B. P. F. A. GOMES et al
..
Gomes B P; Lilley J D; Drucker D BGomes B P; Lilley J D; Drucker D B
Journal of dentistry
1996;24(1-2):47-55.
Journal of dentistry
1996;24(1-2):47-55.
-The aim of this study was to examine a more -The aim of this study was to examine a more
extensive series of canals microbiologically, to extensive series of canals microbiologically, to
determine whether any other particular endodontic determine whether any other particular endodontic
symptoms or clinical signs showed specific symptoms or clinical signs showed specific
associations with individual bacterial species. associations with individual bacterial species.
: Seventy root canals were examined : Seventy root canals were examined
microbiologically and clinical data collected to microbiologically and clinical data collected to
investigate in detail such associations. investigate in detail such associations.

Of the canals studied, 37 were associated with Of the canals studied, 37 were associated with
pain, 49 with tenderness to percussion, 23 with pain, 49 with tenderness to percussion, 23 with
swelling, six with purulent exudate and 57 swelling, six with purulent exudate and 57
presented with wet root canals. presented with wet root canals.
Anaerobes were isolated from 70.3% of painful Anaerobes were isolated from 70.3% of painful
canals and from 29.7% of pain-free canals. canals and from 29.7% of pain-free canals.
Significant associations were found between (a) Significant associations were found between (a)
pain and either Prevotella spp. or pain and either Prevotella spp. or
peptostreptococci, both peptostreptococci, both
tenderness to percussion and Prevotella spp. or tenderness to percussion and Prevotella spp. or
anaerobes .anaerobes .
swelling and Eubacterium spp. (P < 0.01), or with swelling and Eubacterium spp. (P < 0.01), or with
Prevotella spp. Prevotella spp.

wet canal and facultative anaerobes (P < 0.01), wet canal and facultative anaerobes (P < 0.01),
and any one of the genera of Eubacterium, and any one of the genera of Eubacterium,
Peptostreptococcus, Prevotella or Peptostreptococcus, Prevotella or
Propionibacterium .Propionibacterium .
CONCLUSION: It was concluded that several CONCLUSION: It was concluded that several
different endodontic clinical signs and different endodontic clinical signs and
symptoms are significantly associated with symptoms are significantly associated with
specific bacterial species. specific bacterial species.

Kobayashi et al ( 1990) have compared Kobayashi et al ( 1990) have compared
the bacteria isolated from root canals to the bacteria isolated from root canals to
those isolated from the sulcus of a those isolated from the sulcus of a
periodontal pocket .Because similar periodontal pocket .Because similar
species of bacteria were cultivated from species of bacteria were cultivated from
the root canals as from periodontal the root canals as from periodontal
pockets ,they believe that the sulcus is pockets ,they believe that the sulcus is
the source of bacteria in root canal the source of bacteria in root canal
infections . infections .

Inter-relationships of bacteria were Inter-relationships of bacteria were
studied in monkeys (1982)studied in monkeys (1982)
Root canals in the animals were infected Root canals in the animals were infected
with indigenous oral bacteria and then with indigenous oral bacteria and then
sealed in the teeth for intervals up to sealed in the teeth for intervals up to
1080 days . The results showed that a 1080 days . The results showed that a
selective process takes place over time selective process takes place over time
that allows anaerobic bacteria to that allows anaerobic bacteria to
predominate .After 1080 days ,98% of predominate .After 1080 days ,98% of
the bacteria that were cultured from the the bacteria that were cultured from the
canals were strict anaerobes . canals were strict anaerobes .

More recently molecular techniques were used More recently molecular techniques were used
to identify five strains of black – pigmented to identify five strains of black – pigmented
bacteria found to be Prevotella Tannerae .bacteria found to be Prevotella Tannerae .
Using biochemical tests these five strains were Using biochemical tests these five strains were
originally identified as P.intermedia . originally identified as P.intermedia .
 using sodium dodecyl sulfate –polyacrylamide using sodium dodecyl sulfate –polyacrylamide
gel electrophoresis ( SDS-PAGE ) they were gel electrophoresis ( SDS-PAGE ) they were
differentiated from P.intermedia and believed differentiated from P.intermedia and believed
to be P. nigrescens . to be P. nigrescens .
However using molecular methods and However using molecular methods and
comparing gene sequences in a gene bank comparing gene sequences in a gene bank
they have been identified as P.tannerae. they have been identified as P.tannerae.

When 118 samples from endodontic infections When 118 samples from endodontic infections
were examined using polymerase chain reaction were examined using polymerase chain reaction
with specific primers for P .tannerae 60% of the with specific primers for P .tannerae 60% of the
samples were positive for the organism .This samples were positive for the organism .This
suggests that P.Tannaerae is commonly present suggests that P.Tannaerae is commonly present
in endodontic infections but not routinely in endodontic infections but not routinely
cultivable .cultivable .
Nair used both light and electron microscopy to Nair used both light and electron microscopy to
observe micro-organisms both intracellular and observe micro-organisms both intracellular and
extracellular in four symptomatic granulomas and extracellular in four symptomatic granulomas and
one asymptomatic cyst .With 25 other teeth that one asymptomatic cyst .With 25 other teeth that
had asymptomatic ,chronic inflammatory lesions had asymptomatic ,chronic inflammatory lesions
bacteria could not be identified beyond the root bacteria could not be identified beyond the root
apex . Species of Actinomyces and apex . Species of Actinomyces and
Proprionbacterium have been shown to be able to Proprionbacterium have been shown to be able to
persist in inflammatory tissue . persist in inflammatory tissue .

Molander A 1998, have shown that Molander A 1998, have shown that
endodontically treated teeth requiring endodontically treated teeth requiring
retreatment have shown the a prevalence of retreatment have shown the a prevalence of
facultative bacteria especially streptococcus facultative bacteria especially streptococcus
faecalis instead of strict anaerobe that are faecalis instead of strict anaerobe that are
predominant in the initial infectionspredominant in the initial infections . .

Black-pigmented bacteria in coronal and apical Black-pigmented bacteria in coronal and apical
segments of infected root canalssegments of infected root canals
Journal of Endodontics, Volume 24, Issue 5, Journal of Endodontics, Volume 24, Issue 5,
Pages 356-358Pages 356-358
W. DoughertyW. Dougherty ,1994 ,1994
Black-pigmented bacteria (BPB) have been Black-pigmented bacteria (BPB) have been
associated with infections of endodontic origin. associated with infections of endodontic origin.
The purpose of this study was to culture and The purpose of this study was to culture and
identify BPB from the apical and coronal segments identify BPB from the apical and coronal segments
of infected root canals to understand better their of infected root canals to understand better their
ecological relationships. Teeth with a periapical ecological relationships. Teeth with a periapical
radiolucency were extracted and immediately radiolucency were extracted and immediately
placed in reduced transport fluid for transport to an placed in reduced transport fluid for transport to an
anaerobic chamber. anaerobic chamber.

Of 18 sampled roots, 12 were positive for the Of 18 sampled roots, 12 were positive for the
growth of BPB. Eight of the 12 roots with BPB growth of BPB. Eight of the 12 roots with BPB
had a carious exposure of the pulp chamber. had a carious exposure of the pulp chamber.
Seven roots had Prevotella nigrescens in both Seven roots had Prevotella nigrescens in both
the apical and the coronal segments. Six of the apical and the coronal segments. Six of
these seven teeth had carious exposures of these seven teeth had carious exposures of
the pulp chamber. Of the 12 roots infected with the pulp chamber. Of the 12 roots infected with
BPB, six roots had two different species of BPB, six roots had two different species of
BPB, with P. nigrescens always being one of BPB, with P. nigrescens always being one of
the species. P. nigrescens was the most often the species. P. nigrescens was the most often
isolated BPB from both the coronal and apical isolated BPB from both the coronal and apical
segments of infected root canals.segments of infected root canals.

Comparison of the Effectiveness of Bacterial Culture, Comparison of the Effectiveness of Bacterial Culture,
16S rDNA Directed Polymerase Chain Reaction, and 16S rDNA Directed Polymerase Chain Reaction, and
Checkerboard DNA-DNA Hybridization for Detection of Checkerboard DNA-DNA Hybridization for Detection of
Fusobacterium nucleatum in Endodontic InfectionsFusobacterium nucleatum in Endodontic Infections
Journal of Endodontics, Volume 28, Issue 2, Pages 86-89Journal of Endodontics, Volume 28, Issue 2, Pages 86-89
S. Moraes et al ,2005S. Moraes et al ,2005

Thirteen single-root teeth from adult patients, all Thirteen single-root teeth from adult patients, all
having carious lesions, necrotic pulps, and having carious lesions, necrotic pulps, and
radiographic evidence of periradicular bone loss radiographic evidence of periradicular bone loss
were included in this study. Combining all were included in this study. Combining all
methods, the results indicated that F. nucleatum methods, the results indicated that F. nucleatum
was present in approximately 31% (4 of 13) of the was present in approximately 31% (4 of 13) of the
specimens. specimens.
Incidence of F. nucleatum in root canal infections, Incidence of F. nucleatum in root canal infections,
as evaluated in this study by polymerase chain as evaluated in this study by polymerase chain
reaction, culture, and DNA-DNA hybridization, was reaction, culture, and DNA-DNA hybridization, was
15.4%, 15.4%, and 10.0%, respectively. Our data 15.4%, 15.4%, and 10.0%, respectively. Our data
demonstrated that no method used herein could demonstrated that no method used herein could
be considered superior for detecting F. nucleatum be considered superior for detecting F. nucleatum
directly from clinical samples. However, the small directly from clinical samples. However, the small
number of samples examined and the low number of samples examined and the low
prevalence that was observed should be prevalence that was observed should be
considered.considered.

Fusobacterium nucleatum is a Gram-negative, non–Fusobacterium nucleatum is a Gram-negative, non–
spore-forming, nonmotile, obligatory anaerobic rod spore-forming, nonmotile, obligatory anaerobic rod
that is normally isolated from the oral cavity. that is normally isolated from the oral cavity.
Epidemiological studies have shown that this Epidemiological studies have shown that this
species is one of the most prevalent in primary root species is one of the most prevalent in primary root
canal infections. canal infections.
The purpose of this study was to compare the The purpose of this study was to compare the
effectiveness of bacteriological culture, 16S rDNA effectiveness of bacteriological culture, 16S rDNA
directed polymerase chain reaction and directed polymerase chain reaction and
checkerboard DNA-DNA hybridization for detection checkerboard DNA-DNA hybridization for detection
of F. nucleatum strains in infected teeth associated of F. nucleatum strains in infected teeth associated
with periradicular lesions. with periradicular lesions.

Red complex (Bacteroides forsythus, Porphyromonas Red complex (Bacteroides forsythus, Porphyromonas
gingivalis, and Treponema denticola) in endodontic gingivalis, and Treponema denticola) in endodontic
infections: A molecular approachinfections: A molecular approach
[Endodontics][Endodontics]
Rôças, Isabela N. et al.Rôças, Isabela N. et al.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Oral Surgery, Oral Medicine, Oral Pathology, Oral
Radiology & Endodontics:Volume 91(4)April 2001pp Radiology & Endodontics:Volume 91(4)April 2001pp
468-471 468-471

red complex, composed of Bacteroides forsythus, red complex, composed of Bacteroides forsythus,
Porphyromonas gingivalis, and Treponema Porphyromonas gingivalis, and Treponema
denticola, is implicated in severe forms of denticola, is implicated in severe forms of
periodontal diseases. The purpose of this study periodontal diseases. The purpose of this study
was to assess the occurrence of the red complex was to assess the occurrence of the red complex
in root canal infections through the use of a in root canal infections through the use of a
sensitive technique-the 16S rDNA-directed sensitive technique-the 16S rDNA-directed
polymerase chain reaction (PCR). polymerase chain reaction (PCR).
At least 1 member of the red complex was found At least 1 member of the red complex was found
in 33 of 50 cases. T denticola, P gingivalis, and B in 33 of 50 cases. T denticola, P gingivalis, and B
forsythus were detected in 44%, 30%, and 26% of forsythus were detected in 44%, 30%, and 26% of
the cases, respectively. The red complex was the cases, respectively. The red complex was
found in 4 of 50 cases. No particular signs or found in 4 of 50 cases. No particular signs or
symptoms were associated with the presence of symptoms were associated with the presence of
these bacterial species. these bacterial species.

Occurrence of Candida albicans in Infections of Occurrence of Candida albicans in Infections of
Endodontic OriginEndodontic Origin
Journal of Endodontics, Volume 26, Issue 12, Journal of Endodontics, Volume 26, Issue 12,
Pages 695-698Pages 695-698
J. Baumgartner et al,2005.J. Baumgartner et al,2005.
Microorganisms are recognized as the etiological Microorganisms are recognized as the etiological
agent for the majority of pulpal and periradicular agent for the majority of pulpal and periradicular
disease. Although bacteria have been the most disease. Although bacteria have been the most
studied, fungi have also been associated with studied, fungi have also been associated with
infected root canals. The purpose of this study infected root canals. The purpose of this study
was to evaluate the contents of infected root was to evaluate the contents of infected root
canals and aspirates of cellulitis/abscesses of canals and aspirates of cellulitis/abscesses of
endodontic origin for the presence of Candida endodontic origin for the presence of Candida
albicans using the polymerase albicans using the polymerase

chain reaction (PCR). PCR primers specific for the chain reaction (PCR). PCR primers specific for the
18S ribosomal RNA gene of C. albicans were used 18S ribosomal RNA gene of C. albicans were used
to survey 24 samples taken from infected root to survey 24 samples taken from infected root
canals and 19 aspirates from periradicular canals and 19 aspirates from periradicular
infections of endodontic origins. The presence of infections of endodontic origins. The presence of
C. albicans was detected in 5 of 24 (21%) samples C. albicans was detected in 5 of 24 (21%) samples
taken from root canals, but none was detected in taken from root canals, but none was detected in
the periradicular aspirates. The results indicate that the periradicular aspirates. The results indicate that
PCR is an extremely sensitive molecular method PCR is an extremely sensitive molecular method
that may be used to identify C. albicans directly in that may be used to identify C. albicans directly in
samples from infections of endodontic origin.samples from infections of endodontic origin.

Enterococcus faecalis--a mechanism for its role in Enterococcus faecalis--a mechanism for its role in
endodontic failure. Love RM. Int Endod J. 2001 endodontic failure. Love RM. Int Endod J. 2001
Jul;34(5):399-405Jul;34(5):399-405

: : The aim of this study was to identify a The aim of this study was to identify a
possible mechanism that would explain how E. possible mechanism that would explain how E.
faecalis could survive and grow within dentinal faecalis could survive and grow within dentinal
tubules and reinfect an obturated root canal. tubules and reinfect an obturated root canal.
METHODOLOGY: Cells of Streptococcus METHODOLOGY: Cells of Streptococcus
gordonii DL1, Streptococcus mutans NG8, or gordonii DL1, Streptococcus mutans NG8, or
E. faecalis JH2-2 were grown in brain heart E. faecalis JH2-2 were grown in brain heart
infusion broth containing various amounts of infusion broth containing various amounts of
human serum for 56 days. The ability of the human serum for 56 days. The ability of the
three species to invade dentine and bind to three species to invade dentine and bind to
immobilized type I collagen in the presence of immobilized type I collagen in the presence of
human serum was assessed by dentine human serum was assessed by dentine
invasion and microtitre well experiments. invasion and microtitre well experiments.

RESULTS: All three species remained viable RESULTS: All three species remained viable
over the period of the experiment when over the period of the experiment when
grown in human serum. Cells of all three grown in human serum. Cells of all three
bacteria were able to invade dentine and bind bacteria were able to invade dentine and bind
to immobilized collagen. Both of these to immobilized collagen. Both of these
properties were inhibited by the presence of properties were inhibited by the presence of
collagen in the cell solution. collagen in the cell solution.

Human serum inhibited dentine invasion and Human serum inhibited dentine invasion and
collagen adhesion by S. gordonii DL1 and S. collagen adhesion by S. gordonii DL1 and S.
mutans NG8, whilst dentine invasion by E. mutans NG8, whilst dentine invasion by E.
faecalis JH2-2 was reduced in the presence of faecalis JH2-2 was reduced in the presence of
serum, but not inhibited, and binding to serum, but not inhibited, and binding to
collagen was enhanced. collagen was enhanced.
CONCLUSIONS: It is postulated that a CONCLUSIONS: It is postulated that a
virulence factor of E. faecalis in failed virulence factor of E. faecalis in failed
endodontically treated teeth may be related to endodontically treated teeth may be related to
the ability of E. faecalis cells to maintain the the ability of E. faecalis cells to maintain the
capability to invade dentinal tubules and capability to invade dentinal tubules and
adhere to collagen in the presence of human adhere to collagen in the presence of human
serumserum

Recovery of Enterococcus faecalis after single- Recovery of Enterococcus faecalis after single-
or multiple-visit root canal treatments carried or multiple-visit root canal treatments carried
out in infected teeth ex vivo. Vivacqua-Gomes N out in infected teeth ex vivo. Vivacqua-Gomes N
et al , Int Endod J. 2005 Oct;38(10):697-704.et al , Int Endod J. 2005 Oct;38(10):697-704.
To assess the presence of Enterococcus faecalis To assess the presence of Enterococcus faecalis
after root canal treatment in single or multiple after root canal treatment in single or multiple
visits in an ex vivo model. visits in an ex vivo model.
CONCLUSIONS: Neither single- nor multiple-visit CONCLUSIONS: Neither single- nor multiple-visit
root canal treatment ex vivo, eliminated E. faecalis root canal treatment ex vivo, eliminated E. faecalis
completely from dentinal tubules. Up to 60 days completely from dentinal tubules. Up to 60 days
after root filling, E. faecalis remained viable inside after root filling, E. faecalis remained viable inside
dentinal tubules. When no sealer was used, E. dentinal tubules. When no sealer was used, E.
faecalis presented a higher growth rate. faecalis presented a higher growth rate.

Although the initial tissue injury may be Although the initial tissue injury may be
associated with other causes (eg: physical associated with other causes (eg: physical
or chemical trauma) , the majority of or chemical trauma) , the majority of
pathogenic responses are associated with pathogenic responses are associated with
micro-organisms .Microbes have micro-organisms .Microbes have
numerous virulence factors which include numerous virulence factors which include
bacterial capsules, fimbriae, bacterial capsules, fimbriae,
LPS ,enzymes ,extracellular vesicles ,fatty LPS ,enzymes ,extracellular vesicles ,fatty
acids ,polyamines ,ammonia and acids ,polyamines ,ammonia and
hydrogen sulfides . hydrogen sulfides .

Fimbriae and extracellular vesicles may Fimbriae and extracellular vesicles may
participate in aggregation of bacteria or participate in aggregation of bacteria or
attachment to tissue . attachment to tissue .
Pili may extend from one bacterium to another Pili may extend from one bacterium to another
during conjugation and exchange DNA for during conjugation and exchange DNA for
virulence factors including resistance to virulence factors including resistance to
antibiotics . antibiotics .
When LPS is released from the outer When LPS is released from the outer
membrane of gram negative bacteria it is membrane of gram negative bacteria it is
called endotoxin . called endotoxin .

Endotoxin has several biologic effects including Endotoxin has several biologic effects including
activation of complement and bone resorption . activation of complement and bone resorption .
Enzymes are produced by bacteria and are Enzymes are produced by bacteria and are
detrimental to the host . detrimental to the host .
It was recently shown that the gene for It was recently shown that the gene for
collagenase could be detected in stains of collagenase could be detected in stains of
porphyromonas gingivalis but not porphyromonas gingivalis but not
porphyromonas endodontalis isolated from porphyromonas endodontalis isolated from
endodontic infections . endodontic infections .

Collagenase is a metalloprotease that seems Collagenase is a metalloprotease that seems
to be associated with the spread of cellulitis .to be associated with the spread of cellulitis .
Other enzymes produced by bacteria Other enzymes produced by bacteria
neutralize immunoglobins and the components neutralize immunoglobins and the components
of complement .of complement .
In abscesses ,neutrophil lyse and their In abscesses ,neutrophil lyse and their
enzymes to the surrounding milieu to form enzymes to the surrounding milieu to form
purulent exudate . This enzyme-rich exudate purulent exudate . This enzyme-rich exudate
has an adverse affect on the surrounding has an adverse affect on the surrounding
tissues . tissues .

Extracellular vesicles are formed from the outer Extracellular vesicles are formed from the outer
membrane of gram negative bacteria and have membrane of gram negative bacteria and have
a trilaminar structure similar to the parent a trilaminar structure similar to the parent
bacteria . bacteria .
Because they have the same surface antigens Because they have the same surface antigens
they are capable of neutralizing antibodies they are capable of neutralizing antibodies
against the parent organisms . against the parent organisms .
The vesicles may contain enzymes or other The vesicles may contain enzymes or other
toxic agents . toxic agents .

Extracellular vesicles are believed to be Extracellular vesicles are believed to be
involved in hemaagglutination, involved in hemaagglutination,
hemolysis ,bacterial adhesion and proteolytic hemolysis ,bacterial adhesion and proteolytic
action on host tissues . action on host tissues .
Short chain fatty acids most commonly Short chain fatty acids most commonly
produced by bacteria in infected root canals produced by bacteria in infected root canals
are propionic , butyric and isobutyric are propionic , butyric and isobutyric
acids .Short chain fatty acids affect neutrophil acids .Short chain fatty acids affect neutrophil
chemotaxis ,degranulation ,chemiluminescencchemotaxis ,degranulation ,chemiluminescenc
e and phagocytosis .e and phagocytosis .

Butyric acid has the greatest inhibition of T-cell Butyric acid has the greatest inhibition of T-cell
blastogenesis and stimulates the production of blastogenesis and stimulates the production of
interleukin -1 which is associated with bone interleukin -1 which is associated with bone
resorption . Host cells and bacteria produce resorption . Host cells and bacteria produce
polyamines . polyamines .
Polyamines are biologically active compounds Polyamines are biologically active compounds
involved in the regulation of involved in the regulation of
growth ,regeneration of tissues and modulation growth ,regeneration of tissues and modulation
of inflammation .They include spermine, of inflammation .They include spermine,
spermidine,cadaverine and putrescine .spermidine,cadaverine and putrescine .

Polyamines which are produced by both Polyamines which are produced by both
bacteria and host cells are found in infected bacteria and host cells are found in infected
root canals . root canals .
Teeth that are painful to percussion or have Teeth that are painful to percussion or have
spontaneous pain have shown to have a higher spontaneous pain have shown to have a higher
concentration of total polyamines ( specifically concentration of total polyamines ( specifically
putrescine ) in necrotic pulps .putrescine ) in necrotic pulps .

Bacteriological Bacteriological
examination examination
Evidence in favour of bacteriological examination was Evidence in favour of bacteriological examination was
furnished by Buchbinder who showed that 10% more teeth furnished by Buchbinder who showed that 10% more teeth
had healed successfully on post-operative check – up if they had healed successfully on post-operative check – up if they
had a negative culture before obturation . had a negative culture before obturation .
Oliet evaluated 98 teeth some of which yielded positive Oliet evaluated 98 teeth some of which yielded positive
cultures and others negative cultures at the time of root cultures and others negative cultures at the time of root
canal filling and on check up found that a great degree of canal filling and on check up found that a great degree of
success in healing occurred when teeth were filled with no success in healing occurred when teeth were filled with no
evidence of micro-organisms in the root canals . evidence of micro-organisms in the root canals .
In an additional 300 cases reported by Oliet and In an additional 300 cases reported by Oliet and
Sorin ,healing occurred in 11% more cases when the culture Sorin ,healing occurred in 11% more cases when the culture
was negative at the time of root canal filling than when it was was negative at the time of root canal filling than when it was
positive . positive .

Zeldow and Ingle have shown 12 % higher Zeldow and Ingle have shown 12 % higher
success rates under similar circumstances . success rates under similar circumstances .
Heling and Shapiro evaluated 118 teeth 1 to 5 Heling and Shapiro evaluated 118 teeth 1 to 5
years after treatment and found that when years after treatment and found that when
negative cultures had been obtained prior to root negative cultures had been obtained prior to root
canal obturation the success rates was 10 % canal obturation the success rates was 10 %
higher than when canals had been filled without higher than when canals had been filled without
cultures or in the presence of positive culture . cultures or in the presence of positive culture .
Bender and his colleagues questions the Bender and his colleagues questions the
significance of a negative culture during significance of a negative culture during
endodontic treatment these investigators noted endodontic treatment these investigators noted
82% healing response in teeth filled with positive 82% healing response in teeth filled with positive
or negative cultures . or negative cultures .
Eggink found no difference in healing for up to 3 Eggink found no difference in healing for up to 3
years when the root canals were obturated in the years when the root canals were obturated in the
presence of positive or negative cultures from the presence of positive or negative cultures from the
time of filling . time of filling .

Stobberingh and eggink bacteriologically Stobberingh and eggink bacteriologically
examined more than 1800 root canals examined more than 1800 root canals
and found a low incidence of positive and found a low incidence of positive
culture on opening canals of intact culture on opening canals of intact
without periapical rarefactions . These without periapical rarefactions . These
investigators therefore advocate investigators therefore advocate
omission of further bacteriologic tests in omission of further bacteriologic tests in
such cases . such cases .

Culture media Culture media
Although not all micro-organisms present in a root Although not all micro-organisms present in a root
canal grow in readily available culture media . canal grow in readily available culture media .
Several media are needed for the culturing of the Several media are needed for the culturing of the
micro-organisms in the root canal they are as micro-organisms in the root canal they are as
follows : follows :
-Brain heart infusion broth with 0.1% agar Brain heart infusion broth with 0.1% agar
-Trypticase soy broth with 0.1% agar Trypticase soy broth with 0.1% agar
-Thioglycollate Thioglycollate
-And glucose ascitis broth . And glucose ascitis broth .

Leavitt and his colleagues recommended Leavitt and his colleagues recommended
the addition of 0.1% agar in TSA facilitated the addition of 0.1% agar in TSA facilitated
growth of anaerobes .growth of anaerobes .
Others have recommended that addition of Others have recommended that addition of
5% ascitic fluid or 10% horse serum to 5% ascitic fluid or 10% horse serum to
enable fastidious organisms to grow . enable fastidious organisms to grow .
Moreover ,tall tubes filled to a high level Moreover ,tall tubes filled to a high level
should be used for culturing in preference should be used for culturing in preference
to short tubes . to short tubes .

Moller investigated the influence of water Moller investigated the influence of water
quality ,various salts ,organic materials , reducing quality ,various salts ,organic materials , reducing
agents and different methods of obtaining an agents and different methods of obtaining an
oxygen free environment.oxygen free environment.
Viability medium for growth and Stuart’s Viability medium for growth and Stuart’s
transport medium were investigated both equally transport medium were investigated both equally
effective for most species of organisms . The in effective for most species of organisms . The in
vitro test included 156 strains of organisms of 27 vitro test included 156 strains of organisms of 27
species and 18 genera . species and 18 genera .
Most strains survived better in VMG (VIABILITY Most strains survived better in VMG (VIABILITY
MEDIA FOR GROWTH ) especially for MEDIA FOR GROWTH ) especially for
streptococci and anaerobic nonsposporulating streptococci and anaerobic nonsposporulating
organisms . .VMG stored samples showed 90% organisms . .VMG stored samples showed 90%
growth in 3 days . growth in 3 days .

Moller developed a base culture medium Moller developed a base culture medium
containing veal, veal heart ,peptone products in an containing veal, veal heart ,peptone products in an
agar gel and certain supplements . Better growth agar gel and certain supplements . Better growth
was obtained than with commercially dehydrated was obtained than with commercially dehydrated
media . media .
In samplying from root canals of 5000 human In samplying from root canals of 5000 human
teeth ,90 to 95% of positive samples showed teeth ,90 to 95% of positive samples showed
growth after 4 days ,but incubation was continued growth after 4 days ,but incubation was continued
for 2 weeks , to give slow growers time to for 2 weeks , to give slow growers time to
produce a positive result . produce a positive result .
The predominant micro-organisms were identified The predominant micro-organisms were identified
as alpha-hemolytic streptococci , lactobacilli , and as alpha-hemolytic streptococci , lactobacilli , and
anaerobes including gram positive cocci such as anaerobes including gram positive cocci such as
peptococci and streptopeptococci and gram –peptococci and streptopeptococci and gram –
positive rods such as eubacteria ,lactobacilli and positive rods such as eubacteria ,lactobacilli and
corynebacteria .corynebacteria .

Sundqvist used prereduced media ,prepared Sundqvist used prereduced media ,prepared
as described by Holddeman and Moore , as described by Holddeman and Moore ,
and obtained his samples according to a and obtained his samples according to a
procedure associated described by procedure associated described by
Moller .Using an anaerobic glove Moller .Using an anaerobic glove
box ,Sundqvist grew and identified a box ,Sundqvist grew and identified a
predominant number of anaerobes (90%) .predominant number of anaerobes (90%) .
 Griffee and associates found prereduced Griffee and associates found prereduced
thioglycollate medium twice as effective for thioglycollate medium twice as effective for
growing micro-organisms from root canals growing micro-organisms from root canals
as unreduced trypticase soy broth . as unreduced trypticase soy broth .

Taking the culture Taking the culture

Anaerobic culturing Anaerobic culturing
Periradicular sample Periradicular sample
Root canal sample – aseptically prepare an access cavity Root canal sample – aseptically prepare an access cavity
into the pulp chamber into the pulp chamber
Culture reversal – The incidence of culture reversal Culture reversal – The incidence of culture reversal
that is a negative culture that becomes a positive that is a negative culture that becomes a positive
culture by the time of obturation varies with the culture by the time of obturation varies with the
investigator as follows ; Engstrom and Frostell 14%, investigator as follows ; Engstrom and Frostell 14%,
Nicholls 4%, Seltzer and colleagues 16%, Serene Nicholls 4%, Seltzer and colleagues 16%, Serene
and Mcdonald approximately 10%,Tsatsas and and Mcdonald approximately 10%,Tsatsas and
associates 23% when taken by students and associates 23% when taken by students and
Winkler and van Amerongen 3% when taken by Winkler and van Amerongen 3% when taken by
experienced operators and 9% when taken by experienced operators and 9% when taken by
students .students .
. .

This incidence seems to indicate that care in This incidence seems to indicate that care in
taking the culture , ,possible leakage between taking the culture , ,possible leakage between
treatments and the capability of the culture treatments and the capability of the culture
medium to sustain growth of the micro-medium to sustain growth of the micro-
organisms all play a role in culture reversal . organisms all play a role in culture reversal .

Numerous studies have analyzed the Numerous studies have analyzed the
inflammatory cells in a chronic apical periodontitis inflammatory cells in a chronic apical periodontitis
..
The majority of cells associated with The majority of cells associated with
untreated ,infected root canals are T – untreated ,infected root canals are T –
lymphocytes.lymphocytes.
In another study the cells associated with In another study the cells associated with
endodontically treated teeth had more B endodontically treated teeth had more B
Lymphocytes than T Lymphocytes . Thus the Lymphocytes than T Lymphocytes . Thus the
periradicular inflammatory tissue is capable of periradicular inflammatory tissue is capable of
an immunologic response to bacteria and an immunologic response to bacteria and
bacterial byproducts . bacterial byproducts .

Another investigation has shown that samples Another investigation has shown that samples
from root canals associated with symptomatic from root canals associated with symptomatic
periapical lesions contain elevated amount of periapical lesions contain elevated amount of ββ
–Glucoronidase and interleukin 1–Glucoronidase and interleukin 1ββ..
However other mediators including prostanoids However other mediators including prostanoids
,kinins and neuropeptides are involved in the ,kinins and neuropeptides are involved in the
inflammatory response inflammatory response
The antigens of bacteria and bacteria by – The antigens of bacteria and bacteria by –
products stimulate both B cells and T –products stimulate both B cells and T –
cells .For eg LPS can produce both polyclonal cells .For eg LPS can produce both polyclonal
stimulation of B cells and induce macrophage stimulation of B cells and induce macrophage
activation .activation .

Abscesses and cellulitis are the result of bacteria Abscesses and cellulitis are the result of bacteria
invading and infecting periradicular tissues . invading and infecting periradicular tissues .
By definition abscess is an accumulation of By definition abscess is an accumulation of
purulent exudate ,consisting of bacteria ,bacterial purulent exudate ,consisting of bacteria ,bacterial
byproducts ,inflammatory cells ( mainly byproducts ,inflammatory cells ( mainly
neutrophils ) ,lysed inflammatory cells and contents neutrophils ) ,lysed inflammatory cells and contents
of those cells (e.g. : enzymes ) of those cells (e.g. : enzymes )
A cellulitis is defined as a diffuse , A cellulitis is defined as a diffuse ,
erythematous ,mucosal or cutaneous infection that erythematous ,mucosal or cutaneous infection that
may spread to deeper facial spaces and becomes may spread to deeper facial spaces and becomes
life threatening .life threatening .

Fascial spaces are potential anatomical areas Fascial spaces are potential anatomical areas
that exist between the fascia and the that exist between the fascia and the
underlying organs and other tissues .underlying organs and other tissues .
As described by Hohl et al 1983 , the fascial As described by Hohl et al 1983 , the fascial
spaces of the head and neck can be placed spaces of the head and neck can be placed
into four anatomic groups :into four anatomic groups :
-Mandible Mandible
-Cheek and lateral space Cheek and lateral space
-Pharyneal and cervical Pharyneal and cervical
-Midface.Midface.

Swelling of and below the mandible include six Swelling of and below the mandible include six
anatomic areas or fascial spaces .anatomic areas or fascial spaces .
- buccal vestibule - buccal vestibule
- body of the mandible - body of the mandible
- mental space - mental space
- submental space - submental space
- sublingual space - sublingual space
-submandibular space -submandibular space

Mandibular buccal vestibule - it is the Mandibular buccal vestibule - it is the
anatomic space between the buccal anatomic space between the buccal
cortical plate , alveolar mucosa and cortical plate , alveolar mucosa and
buccinator muscle in posterior or buccinator muscle in posterior or
mentalis in the anterior . mentalis in the anterior .

Mental space – it is the potential bilateral Mental space – it is the potential bilateral
anatomic area of the chin that lies anatomic area of the chin that lies
between the mentalis muscle superiorly between the mentalis muscle superiorly
and platsyma muscle inferiorly . and platsyma muscle inferiorly .

Submental space Submental space
infections infections
Clinical features Clinical features
ExtraorallyExtraorally
-Distinct firm swelling in the midline below the -Distinct firm swelling in the midline below the
-Skin overlying the swelling is board like and taut .-Skin overlying the swelling is board like and taut .
-Fluctuation may be present .-Fluctuation may be present .
IntraorallyIntraorally
Anterior teeth are either nonvital, fractured or carious .Anterior teeth are either nonvital, fractured or carious .
Offending tooth may exhibit tenderness on percussion and Offending tooth may exhibit tenderness on percussion and
mobility .mobility .
Patient may experience considerable discomfort on Patient may experience considerable discomfort on
swallowing .swallowing .

Sublingual space – is that potential area Sublingual space – is that potential area
that lies between the oral mucosa of the that lies between the oral mucosa of the
floor of the mouth superiorly and floor of the mouth superiorly and
mylohyoid muscle inferiorly . The lateral mylohyoid muscle inferiorly . The lateral
boundaries of the space are the lingual boundaries of the space are the lingual
surfaces of the mandible . surfaces of the mandible .

Clinical features Clinical features
Extraorally – little / no swelling , lymph Extraorally – little / no swelling , lymph
nodes may be enlarged and tender ,pain nodes may be enlarged and tender ,pain
and discomfort on deglutition .Speech and discomfort on deglutition .Speech
may be affected .may be affected .
Intraorally – firm, swelling in the floor of Intraorally – firm, swelling in the floor of
the mouth on the affected side .The floor the mouth on the affected side .The floor
of the mouth is raised .The tongue may of the mouth is raised .The tongue may
be pushed superiorly .This will bring be pushed superiorly .This will bring
about airway obstruction .about airway obstruction .

Sublingual space Sublingual space

Submandibular space – it is the Submandibular space – it is the
anatomical space that lies between the anatomical space that lies between the
mylohyoid muscle superiorly and mylohyoid muscle superiorly and
platysma muscle inferiorly . platysma muscle inferiorly .

External facial swelling present is moderate External facial swelling present is moderate
in size and is confined to outline of masseter in size and is confined to outline of masseter
muscle that is swelling is seen extending muscle that is swelling is seen extending
from lower border of the mandible to the from lower border of the mandible to the
zygomatic arch and anteriorly to the anterior zygomatic arch and anteriorly to the anterior
border of the masseter and posteriorly to the border of the masseter and posteriorly to the
posterior border of the mandible .posterior border of the mandible .
There is tenderness over the angle of the There is tenderness over the angle of the
mandible .There is complete limitation of mandible .There is complete limitation of
mouth .Often submassentric infection leads mouth .Often submassentric infection leads
to subperiosteal new bone deposition to subperiosteal new bone deposition
beneath the periosteum .Necrosis of the beneath the periosteum .Necrosis of the
muscle can also occur .muscle can also occur .

Submandibular spaceSubmandibular space

Swelling of the lateral face and cheek Swelling of the lateral face and cheek
include four anatomic areas or fascial include four anatomic areas or fascial
spaces spaces
- Buccal vestibule of the maxilla - Buccal vestibule of the maxilla
-Buccal space Buccal space
-Submasseteric space Submasseteric space
-Temporal space Temporal space

Clinical featuresClinical features
External facial swelling present is moderate in External facial swelling present is moderate in
size and is confined to the outline of masseter size and is confined to the outline of masseter
muscle that is swelling is seen extending from the muscle that is swelling is seen extending from the
lower border of the mandible to the zygomatic lower border of the mandible to the zygomatic
arch ,and anteriorly to anterior border of masseter arch ,and anteriorly to anterior border of masseter
and posteriorly posterior border of the mandible . and posteriorly posterior border of the mandible .
There is tenderness over the angle of the There is tenderness over the angle of the
mandible .There is complete limitations of mouth mandible .There is complete limitations of mouth
opening .opening .
Often submassentric infection leads to Often submassentric infection leads to
subperiosteal new bone deposition beneath the subperiosteal new bone deposition beneath the
periosteum .periosteum .
Necrosis of the muscle can also occur .Necrosis of the muscle can also occur .

Temporal spaces Temporal spaces
Deep temporal –it is the space between Deep temporal –it is the space between
the lateral surface of the skull and the lateral surface of the skull and
medial surface of the temporalis muscle medial surface of the temporalis muscle
Whereas superficial space lies between Whereas superficial space lies between
the temporalis muscle and overlying the temporalis muscle and overlying
fascia . fascia .

Clinical features Clinical features
Pain Pain
Trismus Trismus
Swelling over the temporal region may or Swelling over the temporal region may or
may not be present . may not be present .

Swelling of pharyngeal and cervical areas Swelling of pharyngeal and cervical areas
include the following fascial spaces .include the following fascial spaces .
-Ptergomandibular space Ptergomandibular space
-Paraparyngeal space Paraparyngeal space
-Cervical spaces Cervical spaces

Clinical features of pterygomandibular space Clinical features of pterygomandibular space
Even established cases of pterygomandibular space Even established cases of pterygomandibular space
infections do not cause much swelling of face over the infections do not cause much swelling of face over the
submandibular region .However there is severe degree of submandibular region .However there is severe degree of
limitation of mouth opening .limitation of mouth opening .
Tenderness can be elicited over the area of soft tissues Tenderness can be elicited over the area of soft tissues
medial to anterior border of the ramus of the mandible . medial to anterior border of the ramus of the mandible .
Dysphagia is present .Dysphagia is present .
Medial displacement of lateral wall of the pharynx ,redness Medial displacement of lateral wall of the pharynx ,redness
and odema of the area around 3 rd molar . and odema of the area around 3 rd molar .
Midline of the palate is displaced to unaffected side and Midline of the palate is displaced to unaffected side and
uvula is swollen.uvula is swollen.
Difficulty in breathing .Difficulty in breathing .

Parapharyngeal space Parapharyngeal space
Comprises of lateral pharngeal and Comprises of lateral pharngeal and
retropharngeal spaces . retropharngeal spaces .
Parapharyngeal space is bilateral and lies Parapharyngeal space is bilateral and lies
between lateral surface of medial pterygoid between lateral surface of medial pterygoid
muscle and the posterior surface of superior muscle and the posterior surface of superior
constrictor muscle . constrictor muscle .
Retropharngeal space lies between the Retropharngeal space lies between the
anterior surface of prevertebral fascia and anterior surface of prevertebral fascia and
posterior surface of superior constrictor posterior surface of superior constrictor
muscle . muscle .

Clinical features is grave because of generalized Clinical features is grave because of generalized
septicemia and respiratory embrassement due to septicemia and respiratory embrassement due to
edema of the larynx .edema of the larynx .
Generalized constitutional symptoms in the form of Generalized constitutional symptoms in the form of
malaise and pyrexia are presented . malaise and pyrexia are presented .
Extraorally – there is brawny induration of the face Extraorally – there is brawny induration of the face
over the angle of the mandible .This may extend over the angle of the mandible .This may extend
downward to the submandibular region as well as downward to the submandibular region as well as
upwards to the parotid region of ipsilateral side . upwards to the parotid region of ipsilateral side .
Intraorally – anterior part of the lateral pharyngeal Intraorally – anterior part of the lateral pharyngeal
wall may be swollen that pushes the soft palate wall may be swollen that pushes the soft palate
and palatine tonsils towards the midline . Severe and palatine tonsils towards the midline . Severe
pain arising from the collection of pus between pain arising from the collection of pus between
medial pterygoid and superior medial pterygoid and superior
constrictor .Dysphagia is present . constrictor .Dysphagia is present .

Swellings of the midface consists of four Swellings of the midface consists of four
anatomic areas and spaces . anatomic areas and spaces .
-Palate Palate
-Base of the upper lip Base of the upper lip
-Canine spaces Canine spaces
-Periorbital spaces Periorbital spaces

Clinical features of canine Clinical features of canine
fossa infection fossa infection
Swelling of cheek and upper lip Swelling of cheek and upper lip
Obliteration of nasolabial fold (pus accumates Obliteration of nasolabial fold (pus accumates
in the canine fossa ) in the canine fossa )
Drooping of the corner of the mouth .Drooping of the corner of the mouth .
Odema of the lower eyelid Odema of the lower eyelid
Extraorally usually on the first or second day Extraorally usually on the first or second day
there is inflammatory enlargement of the there is inflammatory enlargement of the
upper lip and the angle of the mouth is seen to upper lip and the angle of the mouth is seen to
droop . Obliteration of nasolabial fold . droop . Obliteration of nasolabial fold .
Periorbital oedema .Periorbital oedema .

Late phase :Late phase :
This usually occurs on 2This usually occurs on 2
ndnd
or 3 or 3
rdrd
day ,marked day ,marked
periorbital oedema forcing the eyelid to close .periorbital oedema forcing the eyelid to close .
Redness and marked tenderness of the facial Redness and marked tenderness of the facial
tissues .tissues .
When infection spreads to chronic stage it may When infection spreads to chronic stage it may
result in production of chronic fistula in the cleft result in production of chronic fistula in the cleft
area between the levator labii superioris alaque area between the levator labii superioris alaque
nasi and zygomaticus minor muscles near the nasi and zygomaticus minor muscles near the
medial canthus of the eye .medial canthus of the eye .

Management of abscess Management of abscess
and cellulitis . and cellulitis .
There are two important elements of effective There are two important elements of effective
patient management :patient management :
-Correct diagnosis Correct diagnosis
-and removal of the cause of an endodontic and removal of the cause of an endodontic
infection . infection .
-Antibiotic are not recommended for irreversible Antibiotic are not recommended for irreversible
pulpitis , acute apical periodontitis , a draining pulpitis , acute apical periodontitis , a draining
sinus tract, after endodontic surgery , to prevent sinus tract, after endodontic surgery , to prevent
flare ups or after incision for drainage of a flare ups or after incision for drainage of a
localized swelling . localized swelling .

Ideally susceptibility testing should be done Ideally susceptibility testing should be done
when antibiotics are to be prescribed . when antibiotics are to be prescribed .
However antibiotics often are prescribed However antibiotics often are prescribed
empirically because testing on strict anaerobes empirically because testing on strict anaerobes
may take several days to weeks and many may take several days to weeks and many
organisms are not cultivable .organisms are not cultivable .
Empiric prescription of antibiotics is based on a Empiric prescription of antibiotics is based on a
knowledge of the organisms most likely knowledge of the organisms most likely
associated with endodontic infections . associated with endodontic infections .

1) Pencillin VK Pencillin VK
Narrow spectrum of microbial activity .Narrow spectrum of microbial activity .
It includes most of the bacteria most often identified It includes most of the bacteria most often identified
for endodontic infections ,including both facultative for endodontic infections ,including both facultative
and anaerobic bacteria . and anaerobic bacteria .
It remains the drug of choice because of its efficacy It remains the drug of choice because of its efficacy
and low toxicity . and low toxicity .
However all of the pencillins have up to 10% allergy However all of the pencillins have up to 10% allergy
rate ,which is a major concern . rate ,which is a major concern .
An oral dose of 1000mg should be followed by An oral dose of 1000mg should be followed by
500mg every 6 hours for 6 to 10 days .For severe 500mg every 6 hours for 6 to 10 days .For severe
infections the antibiotic may be described every 4 infections the antibiotic may be described every 4
hours to maintain a more constant serum level.hours to maintain a more constant serum level.

2 .2 .Amoxicillin Amoxicillin
It is a broad spectrum antiobiotic It is a broad spectrum antiobiotic
It includes bacteria usually not isolated It includes bacteria usually not isolated
from endodontic infections .from endodontic infections .
It is rapidly absorbed and gives a more It is rapidly absorbed and gives a more
sustained serum level .sustained serum level .
However ,because of its wider spectrum ,it However ,because of its wider spectrum ,it
will select for more resistant organisms will select for more resistant organisms
especially in the gastrointestinal tract . especially in the gastrointestinal tract .
An oral loading dose of 1000mg of An oral loading dose of 1000mg of
amoxicillin should be followed by 500mg amoxicillin should be followed by 500mg
every 8 hours for 6 to 10 days .every 8 hours for 6 to 10 days .

The combination of amoxicillin with The combination of amoxicillin with
clavulanate is not recommended for clavulanate is not recommended for
endodontic infections unless it is endodontic infections unless it is
determined that determined that ββ- lacatamase –producing - lacatamase –producing
bacteria are causing the infection . bacteria are causing the infection .

3 .3 .Clarithromycin and azithromycinClarithromycin and azithromycin
They are macrolides .They are macrolides .
They are effective against some of the They are effective against some of the
anaerobic species of bacteria associated with anaerobic species of bacteria associated with
endodontic infections .endodontic infections .
They may be considered for mild infections in They may be considered for mild infections in
patients allergic to pencillin but do not have a patients allergic to pencillin but do not have a
long –term track record . long –term track record .
They produce less gastrointestinal upset . They produce less gastrointestinal upset .
Clarithromycin may be given with or without Clarithromycin may be given with or without
meals in a dose of 250 to 500 mg every 12 meals in a dose of 250 to 500 mg every 12
hours for 6 to 10 days .Aziththromycin should hours for 6 to 10 days .Aziththromycin should
be taken 1 hour before meals or 2 hours after be taken 1 hour before meals or 2 hours after
meals ,with a loading dose of 500mg on the meals ,with a loading dose of 500mg on the
first day, followed by 250mg daily. first day, followed by 250mg daily.

These antimicrobials block the These antimicrobials block the
metabolism of a number of drugs so care metabolism of a number of drugs so care
must be taken to check interaction with must be taken to check interaction with
other drugs the patient may be taking . other drugs the patient may be taking .
They block the metabolism of warfarin They block the metabolism of warfarin
and anisindione ,which can lead to and anisindione ,which can lead to
serious bleeding in anticoagulated serious bleeding in anticoagulated
patients . patients .

4.4.MetronidazoleMetronidazole
It is an antimicrobial with excellent activity against It is an antimicrobial with excellent activity against
strict anaerobes but ineffective against facultative strict anaerobes but ineffective against facultative
bacteria . bacteria .
It can be used in conjunction with pencillin when It can be used in conjunction with pencillin when
the latter does not seem to be effective after 2 to 3 the latter does not seem to be effective after 2 to 3
days of therapy without improvement of the days of therapy without improvement of the
patients signs and symptoms .patients signs and symptoms .
Metronidazole is prescribed in a loading dose of Metronidazole is prescribed in a loading dose of
500 mg ,followed by 250-500mg every 6 hours . 500 mg ,followed by 250-500mg every 6 hours .
Pencillin should be continued because Pencillin should be continued because
metronidazole is not effective against facultative metronidazole is not effective against facultative
bacteria . bacteria .

Patients taking metronidazole should not Patients taking metronidazole should not
consume alcohol during therapy and for at consume alcohol during therapy and for at
least 3 days afterward because of a disulfiram least 3 days afterward because of a disulfiram
type of reaction . Likewise metronidazole type of reaction . Likewise metronidazole
should be avoided in patients taking lithium . should be avoided in patients taking lithium .

55. Clindamycin. Clindamycin
Recommended for patients with a serious Recommended for patients with a serious
infection and allergy to pencillin . infection and allergy to pencillin .
It is effective against both facultative and strict It is effective against both facultative and strict
anaerobes .anaerobes .
It is distributed throughout the body and It is distributed throughout the body and
concentrates in the bone .concentrates in the bone .
Although antibiotic associated colitis has been Although antibiotic associated colitis has been
linked to clindamycin it only rarely occurs in doses linked to clindamycin it only rarely occurs in doses
recommended for endodontic infections.recommended for endodontic infections.
Clindamycin should be prescribed with a 300mg Clindamycin should be prescribed with a 300mg
loading dose and then 150 to 300mg every 6 loading dose and then 150 to 300mg every 6
hours for 6 to 10 days . . hours for 6 to 10 days . .

Prophylactic regimens for Prophylactic regimens for
dental procedures dental procedures

THEORY OF FOCAL THEORY OF FOCAL
INFECTION INFECTION
In 1904 ,F . Billings described a focus of In 1904 ,F . Billings described a focus of
infection as a circumscribed area of tissue infection as a circumscribed area of tissue
infected with pathogenic organisms . infected with pathogenic organisms .
One of his students was E.C Rosenow who in One of his students was E.C Rosenow who in
1909 described the theory of focal infection as 1909 described the theory of focal infection as
– a localized or generalized infection caused – a localized or generalized infection caused
by bacteria travelling through bloodstream from by bacteria travelling through bloodstream from
a distant focus of infection . a distant focus of infection .

In 1910 Dr William Hunter , a British physician presented a In 1910 Dr William Hunter , a British physician presented a
lecture , the role of Sepsis and antisepsis in medicine to lecture , the role of Sepsis and antisepsis in medicine to
the faculty of McGill university in Montreal .His the faculty of McGill university in Montreal .His
presentation severely criticized dentistry in the united presentation severely criticized dentistry in the united
states and inadvertently affected the practice of root canal states and inadvertently affected the practice of root canal
therapy for 40 years . In his address hunter stated :therapy for 40 years . In his address hunter stated :
Gold fillings , gold caps, gold bridges gold crowns fixed Gold fillings , gold caps, gold bridges gold crowns fixed
dentures , built in ,on and around diseased teeth form a dentures , built in ,on and around diseased teeth form a
veritable mausoleum of gold over a mass of sepsis to veritable mausoleum of gold over a mass of sepsis to
which there is no parallel in the whole realm of medicine or which there is no parallel in the whole realm of medicine or
surgery . The medical ill effects of this septic surgery are surgery . The medical ill effects of this septic surgery are
to be seen every day in those who are the victims of this to be seen every day in those who are the victims of this
glided dentistry – in their dirty gray , sallow ,pale waxlike glided dentistry – in their dirty gray , sallow ,pale waxlike
complexions and in the chronic dyspepsias , intestinal complexions and in the chronic dyspepsias , intestinal
disorders , ill health ,anemia's and nervous complaints disorders , ill health ,anemia's and nervous complaints
from which they suffer . from which they suffer .

The cause of the illness discussed in hunter’s The cause of the illness discussed in hunter’s
address was misdirected to teeth with nonvital address was misdirected to teeth with nonvital
pulps and endodontically treated teeth . In reality pulps and endodontically treated teeth . In reality
hunter was referring to infections found around hunter was referring to infections found around
poorly fabricated restorations . poorly fabricated restorations .
As a result many dentists appropriately callec one As a result many dentists appropriately callec one
hundred percenters needlessly extracted all teeth hundred percenters needlessly extracted all teeth
that had nonvital pulps or that had undergone that had nonvital pulps or that had undergone
endodontic treatment .endodontic treatment .
During this period , case histories reporting cures During this period , case histories reporting cures
after extraction of teeth appeared in the dental after extraction of teeth appeared in the dental
literature .Although these reports were empirical literature .Although these reports were empirical
and without appropriate follow –up they wrongfully and without appropriate follow –up they wrongfully
justified the continued unwarranted extraction of justified the continued unwarranted extraction of
teeth for approximately 20 years . teeth for approximately 20 years .

Using Rosenow’s theory of elective localization of Using Rosenow’s theory of elective localization of
bacteria ( theory of focal infection ) Dr Westin Price bacteria ( theory of focal infection ) Dr Westin Price
the chairman of the ADA Research section the chairman of the ADA Research section
conducted a study on relationship of teeth infected conducted a study on relationship of teeth infected
nonvital pulps or endodontically treated teeth with nonvital pulps or endodontically treated teeth with
degenerative chronic illnessess.His work which degenerative chronic illnessess.His work which
basically supported Rosenow’S theory was basically supported Rosenow’S theory was
published in 1923 in two books dental infections : published in 1923 in two books dental infections :
oral and systemic and dental infections and the oral and systemic and dental infections and the
degenerative diseases .degenerative diseases .

In 1930 the following editorial rejecting the focal In 1930 the following editorial rejecting the focal
infection theory and the needless extraction of infection theory and the needless extraction of
teeth appeared in Dental Cosmos : teeth appeared in Dental Cosmos :
The policy of indiscriminate extraction of all teeth The policy of indiscriminate extraction of all teeth
in which the pulps are involved has been in which the pulps are involved has been
practiced sufficiently long to convince the most practiced sufficiently long to convince the most
rabid hundred percenter that it is irrational and rabid hundred percenter that it is irrational and
does not meet the demands of either medical or does not meet the demands of either medical or
dental requirements and much less those of the dental requirements and much less those of the
patient . Now let us turn from the destructive patient . Now let us turn from the destructive
policy , the path of least resistance to the policy , the path of least resistance to the
constructive even though it be beset with more constructive even though it be beset with more
difficulties it certainly offers more possibilities of difficulties it certainly offers more possibilities of
making the masticatory apparatus a useful and making the masticatory apparatus a useful and
helpful organ rather than a crippled and constant helpful organ rather than a crippled and constant
menance to the patient . menance to the patient .

In 1938 two physicians Dr R.I Cecil and Dr D.M. Angevine In 1938 two physicians Dr R.I Cecil and Dr D.M. Angevine
reported in the annals of internal medicine on a follow =up reported in the annals of internal medicine on a follow =up
study of 156 patients with rheumatoid arthritis who had study of 156 patients with rheumatoid arthritis who had
teeth or tonsils removed because they were considered teeth or tonsils removed because they were considered
foci of infection .OF the 52 patients who had teeth foci of infection .OF the 52 patients who had teeth
extracted 47 did not improve and three became even more extracted 47 did not improve and three became even more
ill. This study was especially interesting because Cecil had ill. This study was especially interesting because Cecil had
been a strong advocate of the focal infection theory .Cecil been a strong advocate of the focal infection theory .Cecil
suggested that the focal infection theory should be suggested that the focal infection theory should be
redresses and the further removal of foci of infection redresses and the further removal of foci of infection
curtailed . In other words subjective improvements of curtailed . In other words subjective improvements of
symptoms after extraction of a tooth did not seem that the symptoms after extraction of a tooth did not seem that the
tooth was the cause of the illness .tooth was the cause of the illness .
It later was determined that the scientific method used by It later was determined that the scientific method used by
Rosenow and price was flawed in three major areas :Rosenow and price was flawed in three major areas :
-Massive doses of bacteria were injected into the Massive doses of bacteria were injected into the
experimental animals .experimental animals .
-The experiments were not adequately controlled .The experiments were not adequately controlled .
-The specificity of the bacteria involved was not proven . The specificity of the bacteria involved was not proven .

Microbiologic studies also disputed the studies by Microbiologic studies also disputed the studies by
Rosenow and Price .Fish and Mclean found that the root Rosenow and Price .Fish and Mclean found that the root
surfaces of extracted teeth and corresponding alveolar surfaces of extracted teeth and corresponding alveolar
socket were contaminated from the gingival sulcus during socket were contaminated from the gingival sulcus during
extraction .Others reported that bacteriologic examination extraction .Others reported that bacteriologic examination
of the root surfaces of extracted teeth had no scientific of the root surfaces of extracted teeth had no scientific
standing unless of the gingival tissues had been cauterized standing unless of the gingival tissues had been cauterized
before extraction and that bacteria could be forced into the before extraction and that bacteria could be forced into the
pulp tissue during extraction because of the pressure pulp tissue during extraction because of the pressure
incurred during rocking of the tooth . incurred during rocking of the tooth .
As a result of clinical and scientific studies both the medical As a result of clinical and scientific studies both the medical
and scientific studies concluded that no relationship exists and scientific studies concluded that no relationship exists
between the teeth with nonvital pulps or endodontically between the teeth with nonvital pulps or endodontically
treated teeth and any of the so – called degenerative treated teeth and any of the so – called degenerative
diseases . Although the focal infection theory resulted in diseases . Although the focal infection theory resulted in
needless extraction of millions of teeth it definitely needless extraction of millions of teeth it definitely
encouraged research that eventually led to current encouraged research that eventually led to current
scientific and biologic basis for root canal treatment . scientific and biologic basis for root canal treatment .

Summary and conclusion Summary and conclusion
It is important that clinicans understand the close It is important that clinicans understand the close
relationship of micro-organisms with endodontic relationship of micro-organisms with endodontic
diseases to develop an effective treatment rationale . diseases to develop an effective treatment rationale .
Retreatment procedures are less predictable than Retreatment procedures are less predictable than
treatment of primary endodontic cases .This is due to treatment of primary endodontic cases .This is due to
the specific more resistant species of micro-the specific more resistant species of micro-
organisms which can survive not only during organisms which can survive not only during
antimicrobial treatment but also rootfilling procedure .antimicrobial treatment but also rootfilling procedure .
It is essential that further information is needed to get It is essential that further information is needed to get
a thorough knowledge about residual post-treatment a thorough knowledge about residual post-treatment
root infection and post-treatment apical periodontitis in root infection and post-treatment apical periodontitis in
order to improve quality of root canal debridement order to improve quality of root canal debridement
procedures . procedures .

References References
Pathway of pulp –Cohen Burns (8Pathway of pulp –Cohen Burns (8
thth
edition ) edition )
Pathway of pulp –Cohen Burns (9Pathway of pulp –Cohen Burns (9
thth
edition ) edition )
Textbook of endodontics – Ingle Textbook of endodontics – Ingle
Endodontic practice – Louis Grossman (11Endodontic practice – Louis Grossman (11
THTH

edition ) edition )
Principles and practice of endodontics – Principles and practice of endodontics –
Walton Torabinejad (3Walton Torabinejad (3
rdrd
edition ) edition )
Textbook of oral and maxillofacial surgery – Textbook of oral and maxillofacial surgery –
Neelima Anil Malik .(2Neelima Anil Malik .(2
ndnd
edition ) edition )
Textbook of microbiology – Bhatia Textbook of microbiology – Bhatia

Micro-organisms in root canal infections : a review .Vytaute Micro-organisms in root canal infections : a review .Vytaute
Peciuliene et al ,2008.Peciuliene et al ,2008.
Relationship between Incidence of Black-pigmented Anaerobic Relationship between Incidence of Black-pigmented Anaerobic
Rods and Clinical Symptoms on Traumatic Non-vital Teeth Rods and Clinical Symptoms on Traumatic Non-vital Teeth
IINO FUMIAKI et al Japanese Journal of Conservative IINO FUMIAKI et al Japanese Journal of Conservative
Dentistry(2003)Dentistry(2003)
Relationship between clinical symptoms and enzyme-producing Relationship between clinical symptoms and enzyme-producing
bacteria isolated from infected root canals. Hashioka K et al , J bacteria isolated from infected root canals. Hashioka K et al , J
Endo ,20(2),1994Endo ,20(2),1994
Recovery of Enterococcus faecalis after single- or multiple-visit Recovery of Enterococcus faecalis after single- or multiple-visit
root canal treatments carried out in infected teeth ex vivo. root canal treatments carried out in infected teeth ex vivo.
Vivacqua-Gomes N et al , Int Endod J. 2005 Oct;38(10):697-704Vivacqua-Gomes N et al , Int Endod J. 2005 Oct;38(10):697-704

Quantification of endotoxins in necrotic root canals from Quantification of endotoxins in necrotic root canals from
symptomatic and asymptomatic teeth.symptomatic and asymptomatic teeth.
Rogerio C Jacinto, J Med Microbiol 54 (2005 ).Rogerio C Jacinto, J Med Microbiol 54 (2005 ).
Association between Bacteroides forsythus in the infected root Association between Bacteroides forsythus in the infected root
canals and clinical symptoms of chronic apical periodontitis] canals and clinical symptoms of chronic apical periodontitis]
Huang DM Sichuan Da Xue Xue Bao Yi Xue Ban. 2005 Huang DM Sichuan Da Xue Xue Bao Yi Xue Ban. 2005
Jan;36(1):46-9Jan;36(1):46-9
Invasion of dentinal tubules by oral bacteria. Love RM, Jenkinson Invasion of dentinal tubules by oral bacteria. Love RM, Jenkinson
HF. Crit Rev Oral Biol Med. 2002;13(2):171-83HF. Crit Rev Oral Biol Med. 2002;13(2):171-83
Observation of bacteria and fungi in infected root canals and Observation of bacteria and fungi in infected root canals and
dentinal tubules by SEMdentinal tubules by SEM
B. H. Sen et al , dental traumatology , volume 11, issue 1 ,2007B. H. Sen et al , dental traumatology , volume 11, issue 1 ,2007


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