The document discusses microbial shifts and their relationship to periodontitis. It begins by explaining how biofilms form and provide advantages to bacteria, including increased attachment, metabolic cooperation, antibiotic resistance, and avoidance of the immune system. Quorum sensing allows bacteria to communicate and maintain homeostasis. However, homeostasis can break down, leading to shifts in the microbial balance that predispose sites to disease. Specifically, the subgingival microflora shifts from mainly gram-positive to increased gram-negative anaerobic bacteria. Adjunctive treatments for periodontitis are discussed, including antibiotics, antiseptics, host modulation therapy, photodynamic therapy, and probiotic therapy. The efficacy of treatment is assessed both biologically by examining

1. GOOD MORNING

2. MICROBIAL SHIFT AND PERIODONTITIS
Berezow A B, Darveau R P
Perio 2000 2011;55:36-47
GUIDED BY:
DR. AMIT GOEL
PRESENTED BY:
DR. VIRSHALI GUPTA
PG 2ND YEAR

3. CONTENTS
Introduction
Biofilm formation
Advantages of biofilm
Quorum sensing
Biofilm and oral health
Microbial shift leading to periodontitis
Fighting oral biofilms: adjunctive treatments for periodontitis
Conclusion

4. INTRODUCTION
MICROBIAL
IMMUNOLOGICAL

5. BIOFILM FORMATION
Carbohydrate
degraders

6. ADVANTAGES OF BIOFILM
Increased ability to
attach to surfaces---by
pili and by extracellular
polymeric substance
(Davey ME et al 2000).
Metabolic cooperation,
wherein the waste
product of one bacterial
species serves as the
food source for another.
Resistance to
antibiotics that easily
kill bacteria growing in
planktonic culture.
Avoid the host immune
system. Antibodies
unable to perforate the
matrix (Fux CA et al)..

7. QUORUM SENSING

8. The bacterial composition of plaque remains relatively
stable despite regular exposure to minor environmental
perturbations.
This stability (microbial homeostasis) is due to a dynamic
balance of both synergistic and antagonistic microbial
interactions.
However, homeostasis can break down, leading to shifts in
the balance of the microflora, thereby predisposing sites
to disease.
The subgingival microflora shifts from being mainly Gram
positive to being comprised of increased levels of
obligately anaerobic, asaccharolytic Gram-negative
organisms.
BIOFILMS AND HUMAN HEALTH

9. Over 700 sps have been detected in the oral cavity, over half of which have never
been cultivated. (Aas JA 2005)
Substantial diversity in the content of the microflora between individuals and
between different oral sites within the same individual.
Dietary changes combined with poor hygiene can cause a shift in the
composition of the oral microflora.
Bacteria also appear to be associated with oral health. For instance, a positive
association has been observed between oral health and the presence of Veillonella
(Kumar PS et al 2006) or Capnocytophaga ochracea (Riep B et al 2003).

10. SHIFT TO…
Non motile
Motile

11. MICROBIAL SHIFT LEADING TO PERIoDONTITIS
GRAM POSITIVE AEROBES GRAM NEGATIVE ANAEROBES
 Gradually changes the symbiotic host–microbe relationship to a
pathogenic one.
Prevotella intermedia
Fusobacterium
nucleatum
P. Gingivalis
Tannerella forsythia
Treponema denticola

12.  However, recent research
has challenged this
paradigm. periodontal
pathogens such as P.
gingivalis and T. forsythia
could also be frequently
isolated from healthy
controls. –Riep et al 2009
ON THE CONTRARY…
Kumar et al. 2006 directly
contradicted the existing
pattern when they observed
that the gram-negative
bacterium Veillonella was
associated with periodontal
health, while the gram
positive anaerobe Filifactor
alocis was associated with
disease.

13. FIGHTING ORAL BIOFILMS:
ADJUNCTIVE TREATMENTS FOR
PERIODONTITIS

14. An adjunct to scaling and root planing, and they can be applied
locally or administered systemically.
Local, sustained-release minocycline significantly improved patient
outcomes when compared to scaling and root planing alone.
Using multiple antibiotics simultaneously leaves a patient
susceptible to developing an oral yeast infection or experiencing other
severe systemic adverse effects.
Antibiotics do not directly suppress the host inflammatory response
that is largely responsible for the tissue destruction.
antibiotics

15. ANTISEPTICS
 Chlorhexidine, bleach (sodium hypochlorite),
povidone-iodine can be used as an
alternative to antibiotics.
 Chlorhexidine was more effective than
minocycline at destroying P. gingivalis
biofilms in vitro.
 P. gingivalis was completely eradicated after
30 minutes of exposure to chlorhexidine,
povidone-iodine or Listerine.
 Do not address host inflammation.

16. Suppresses the
inflammatory
response by MMPs.
Doxycycline most potent
inhibitor of MMPs. Sub -
antimicrobial doses of
doxycycline used as an
adjunct to SRP showed
improvement in clinical
parameters.
NSAIDS &
bisphosphonates,
Proresolving agent
resolvin E1 could
have potential as
HMTs.
HOSTMODULATIONTHERAPY

17. PHOTODYNAMIC THERAPY
ROS react with essential cellular components
such as DNA, proteins and lipids, leading to cell
death.
Photosensitizers used include dyes (such as
methylene blue, acridine orange and toluidine
blue O),
APDT destroy P. gingivalis, it also inactivates a
virulence-associated protease, as well as the
destructive host inflammatory mediators TNF-α
and IL-1β.

18. The use of probiotics to
treat diseases associated
with a shift in the
microflora. Hence proposed
for the treatment of
periodontitis.
Research showed that when a
mixture of streptococcal sps
was applied to the teeth of
dogs as an adjunct therapy
following root planing, there
was a delay in the re-
colonization of periodontal
pathogens and reduction in
inflammation.
(Teughels W et al 2007)
Use of a mouth rinse
containing Bacillus subtilis or
oral administration of tablets
containing Lactobacillus
salivarius reduces the
number of periodontal
pathogens.
(Mayanagi G et al 2009,
Tsubura S, 2009)
PROBIOTIC THERAPY

19. ASSESSING THE EFFICACY OF TREATMENT
treatment altered the
content of the microflora
and helped to resolve the
host inflammatory
response.
BIOLOGICALLY CLINICALLY
Reduction in probing
pocket depth and
clinical attachment
gain
DNA–DNA checkerboard technique relies upon hybridization of labelled
probe DNA to the genomic DNA isolated from bacterial cells in patient
plaque samples. This technique has been used to determine the nature of
the microbial biofilm before and after treatment of periodontitis.

20.  A reduction in the number of red and orange complex bacteria, as well as a reduction in
the number of sites colonized by these pathogenic bacteria, following various forms of
treatment. ---Haffajee et al 2009
 Following SRP and weekly supragingival plaque removal for 3 months, the microbial
profile of the treated patients was similar to that of periodontally healthy people.
 Thus, the DNA–DNA checkerboard technique is vital to both researchers and clinicians
in characterizing the nature of the biofilms associated with periodontal health and
disease.
 Microarrays and real-time PCR can demonstrate that inflammatory genes were down
regulated in periodontitis patients following therapy. In addition to analyzing the
effectiveness of treatment, this method may also help reveal which host genes are most
responsible for the development and persistence of periodontitis. ---Wang et al 2015
ASSESSING THE EFFICACY OF TREATMENT

21. CONCLUSION
• Oral dysbiosis, or a shift from beneficial symbiotic bacteria to pathogenic
bacteria, is at least partially responsible for the development of
periodontitis. However, despite great advances in our knowledge of the
underlying microbial basis of this disease, the fact remains that
periodontitis has multiple etiologies that have yet to be fully understood.
• Thus, while a microbial shift is known to play a significant role in the
development of periodontitis, genetic, immunological and environmental
factors must also be investigated in order for clinicians and researchers to
fully understand disease progression.

22. THANK YOU