GOOD MORNING

MICROBIAL SHIFT AND PERIODONTITIS Berezow A B, Darveau R PPerio 2000 2011;55:36-47

GUIDED BY: DR. AMIT GOEL

PRESENTED BY:DR. VIRSHALI GUPTAPG 2ND YEAR

CONTENTS

IntroductionBiofilm formationAdvantages of biofilmQuorum sensingBiofilm and oral healthMicrobial shift leading to periodontitisFighting oral biofilms: adjunctive treatments for periodontitisConclusion

INTRODUCTION

MICROBIAL

IMMUNOLOGICAL

BIOFILM FORMATION

Carbohydrate degraders

ADVANTAGES OF BIOFILMIncreased 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)..

QUORUM SENSING

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

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).

SHIFT TO…

gram

po

sitive

cocciNon motile facultative

anaerobes

Fermentin

g speciesGr

am

nega

tive

rodsMotile Obligate

anaerobes

Proteolytic

species

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

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.

FIGHTING ORAL BIOFILMS: ADJUNCTIVE TREATMENTS FOR PERIODONTITIS

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

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.

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.

HOST

MOD

ULAT

ION

THER

APY

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.

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

ASSESSING THE EFFICACY OF TREATMENT

treatment altered the content of the microflora and helped to resolve the host inflammatory response.

BIOLOGICALLY CLINICALLYReduction 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.

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

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.

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