The document discusses the role of microbiology and immunology in endodontics, emphasizing the impact of bacteria on pulpo-periradicular lesions and the necessity for thorough knowledge in this area. It details the microbial ecosystems in root canals, including the types of bacteria involved, factors influencing their growth, and the consequences of biofilm formation on treatment outcomes. Additionally, it outlines methods for effectively combating microbial infections during endodontic procedures, highlighting the importance of proper cleaning, shaping, and the use of antibiotics.

1. MICROBIOLOGY &
IMMUNOLOGY IN
ENDODONTICS
DR.SADASIVA
READER
CHETTINAD HEALTH CITY

2. INTRODUCTION
• Most changes in pulp and
periradicular tissues are of
bacteriological and must be dealt
with as infectious processes.
• Bacteria play a major role in
pathogenesis of pulpo-periradicular
lesion, a fundamental knowledge of
endodontic microbiology needed to
understand.

3. • 1. The role of bacteria in these diseases.
• 2.Pathways of pulp and periradicular
tissues.
• 3. Response of pulpal and periradicular
tissues to bacterial infection.
• 4. Methods used to control and eradicate
root canal infection during root canal
treatment.
• The intact hard tissues of the tooth
normally protect the pulp by acting as
physical barrier.

5. HISTORY
• 1890- Miller – demonstrated
presence of bacteria in necrotic pulp
tissue.
• Predominant species were
streptococci, micrococci, and small
% of anaerobic bacteria.
• Kakehashi etal – experiment with
germ free rats – failed to create
lesions.
• Poly microbial infections.

7. Flora of root canal and
periradicular lesions
• Most of them – multi bacterial.
• Predominance of facultative
organisms
• Obligate anaerobic species
• Gram negative cocci
• Lactobacilli
• spirochetes
• Bacteroides- black pigmented
species

11. MICROBIAL
VIRULENCE&PATHOGENIC
ITY
• In 1965, Hobson gave an equation
showing the relation of number of
microorganisms , their virulence,
resistance of host and severity of the
disease.
• Number of microorganisms x
Virulence of microorganisms = severity of the disease
---------------------------------------------------
resistance of host

13. VARIOUS VIRULENT
FACTORS
• 1. Lipopolysaccharides(lps)
• 2. Extra cellular vesicles
• 3. Enzymes
• 4.Fatty acids
• 5. Polyamines
• 6. Capsule
• 7.Pilli

14. Lipopolysaccharides(LP
S)
Present on the surface of gram
negative bacteria.
LPS HAVE NON SPECIFIC
antigens which are not
neutralized by antibodies.
ENDOTOXINS
Diffuse in to dentin .
Studies have shown the
relationship between endotoxins
and the periradicular
inflammation.

15. EXTRACELLULAR
CELLULAR VESICLES
• Produced by gram-ve bacteria in
the form of endotoxins.
• Vesicles contain various
enzymes and toxic products-responsible
for
haemaggulutination, hemolysis
and bacterial adhesion

16. ENZYMES
• Helps in spread of infection
• Neutralization of the immunoglobulin
and complement components
• PMN leucocytes release hydrolytic
enzymes which degenerate and lyse
to form purulent exudates and have
adverse effects on the surrounding
tissues.

17. FATTY
ACIDS&POLYAMINES
• ANAEROBIC BACTERIA –produces
propionic acid, butryicacid.
• They cause neutrophil chemotaxis,
degranulation,and stimulate
interleukin -1 production which
causes bone resorptionand
periradicular diseases.
• Polyamines are active chemicals
found in infected canals. Cadaverine,
putrescine, spermidine are
polyamines.

18. Factors influencing the
growth and colonization of
microorganisms
• Influence of oxygen
• Nutritional factors
• Bacteriocins
• Coaggregation
• Bacterial relationships

19. Microbial ecosystem of
the root canal system
• NAIDORF summarized the few
generalization in relation to organisms
isolated freom the root canals.
• 1. Mixed infections are more common than
single organisms.
• 2.Pulp contains flora almost similar to that
of oral cavity.
• 3. Approximately 25 % of isolated
organisms are anaerobic.
• 4. organisms isolated from flare-up as well
as asymptomatic cases are almost similar.

20. Microbiology of infected
root canal

21. BIOFILM
• Biofilm is defined as community of
microcolonies of microorganisms in an
aqueous solution that is surrounded by a
matrix made of glycocalyx, which attaches
the bacterial cells to a solid substratum.
• One of basic survival methods- in times of
starvation.
• A BIOFILM has the following attributes:
• Autopoiesis
• Homeostasis
• Synergy
• Communality

25. Classification of biofilms
• Intracanal microbial biofilms
• Extraradicular microbial biofilms-
Enterococcus faecalis responsible
for therapy resistant .
• Periapical microbial biofilms-
Actinomyces and P. propionicum
have been shown to form periapical
lesions resistant to endodontic
therapy.

26. PATHOGENICITYOF
BACTEROIDES
• Related to the presence of LPS and Peptidoglycans
• 1. induce hormones like cytokinins which play
important role in inflammation.
• Stimulate B-lymphocytes
• Activate complement cascade
• Release various enzymes like collgenase
• Enhance production of various pain mediators like
bradykinin,histamine and prostaglandins
• LPS once released as ENDOTOXIN causes
biological effects including inflammationand bone
resorption.

27. Fungi& viruses
• Using PCR, Candida albicans was
detected in 21 % of infected root
canals.
• Bacteriocins are viruses that infect
bacteria and carry DNA in to the
genome of the bacteria. HIV ,
CYTOMEGALO VIRUS, and EPSTEIN
BARR virus – associated with
periapical disease.

28. Microbiology of
periradicular endodontic
infections
• Biofilms are formed in the periapical region
• Periapical lesions contains macrophages,
lymphocytes(T- cells and B-cells), plasma cells, and
neutrophils.
• Their function is to prevent microorganisms from
invading periradicular tissues.
• The mosty common cause of persistent
periradicular infections is incomplete debridement
of the root canal system. Therefore three
dimensional sealing of the rootcanal system is
necessary for resolution of periapical pathologies

29. Microbiology of root
canal failures
• More facultative bacteria rather than
strict anaerobes
• Enterococcus fecalis.
Propionbacterium alactolyticus,
P.propionicum in filled root canal
failure cases.
• Vast majority of endodontic
treatment failures are caused by
intraradicular infections.

30. IDENTIFICATION OF
THE BACTERIA
• GRAMS STAIN- helps in
differentiating Gram positive
and Gram negative organisms.
• CULTURE:
• Molecular diagnostic methods
• DNA- DNA hybridization method
• Polymerase chain reaction

32. How to combat microbes
in the endodontic therapy
• Thorough cleaning & shaping of the root canal system-irrigants
like NAOCL, H2O2, EDTA - excellent tissue
dissolving and microbial agents.
• Oxygenating a canal simply by opening is detrimental to
anaerobes.
• Drainage by canal or by soft tissues decrease discomfort
caused by inflammatory mediators.
• ANTIBIOITICS :Drug of choice is Penicillin vk bcos of
its spectrum of microbial activity against most of the
bacteria associated with endodontic infections and also
of its low toxicity.
• INTRACANAL MEDICAMENTS
• Use of CAOH2, CHX2% TRIPLE ANTIBIOTIC PASTE - is
beneficial in necrotic pulps

33. THANK U