2. Human fetus is sterile but after passing through
birth canal it acquires vaginal and fecal
microorganisms
By 2nd
day Anaerobic flora can be detected in
infant edentulous mouth
Dr Saif Khan 209/10/13
3. Within 2nd week a nearly mature microbiota
is established in the gut of newborn
After weaning(>2yrs), entire human
microbial flora formed by complex collection
of more than 400 types of bacteria.
09/10/13 Dr Saif Khan 3
4. Oral cavity is an “Open growth
system”
Dr Saif Khan 409/10/13
6. Most species colonize on all above described
niches with the exception of spirochetes
Adherence of bacteria to oral epithelial cells
is directly related to its virulence
Dr Saif Khan 609/10/13
7. Teeth and Implants are unique from a
microbiological point of view for two reason
– Provide hard, non-shedding surface that allows for
the development of extensive structured baterial
deposit
– Form a unique ectodermal interruption
A special seal of epithelium and connective
tissue exists between external enviroment
and internal part of body
Dr Saif Khan 709/10/13
8. Teeth are primary habitat for
periopathogens
Thus teeth can be considered as “Port of
entry for Periopathogens
Cariogenic species like S mutans remain
restricted to solid surfaces and are called
“obligate periphyte”
Dr Saif Khan 809/10/13
9. Dental Plaque
Dental plaque is a specific, amorphous, granular
deposit which accumulates on the surface of
teeth, dental restoration and dental calculus.
- -Glickmann
Dr Saif Khan 909/10/13
10. WHO defnition
“Dental plaque is a specific but highly variable
entity resulting from growth and colonization of
micro-organisms on surfaces of teeth,restoration
and soft- tissue consisting of various species
microorganisms entangled in extracellular matrix.”
Dr Saif Khan 1009/10/13
11. Dental plaque
• Defined clinically as structured, reselient,
yellowish-grayish substance that adhere
tenaciously to the intraoral hard
surface,including removable and fixed
restoration.
• Plaque is primarily composed of bacteria in
matrix of salivary glycoproteins and
extracellular polysaccharides
• 1gm of dental plaque(wet weight) contains 1011
bacteria
Dr Saif Khan 1109/10/13
12. 09/10/13 Dr Saif Khan 12
Thin supragingival dental plaque of a 32-year-old man who had
not brushed his teeth for 7 days. A, Unstained plaque is not
readily apparent. B, Extent of the plaque becomes apparent
when stained with a disclosing solution (i.e.,erythrosine dye)
13. No of bacteria in
Supragingival plaque on single tooth – 109
GingivalCrevice-
103
Deepperiodontalpocket-
108
More than 500 distinct microbial species are
found in dental plaque
Non bacterial microorganism found in plaque
include Mycoplasma species, yeasts, Protozoa
and Viruses
Dr Saif Khan 1309/10/13
14. Dental plaque is broadly Classified into
Dr Saif Khan 1409/10/13
20. The enviromental paramaters of subgingival region is
different from supragingival region
– Gingival crevice is bathed by GCF which may
contains many substances that bacteria may use
as nutrients
– Low oxygen tension in the subgingival area
– Host inflammatory cells and mediators have
considerable influence on establishment and
growth of bacteria
Dr Saif Khan 2009/10/13
21. The apical border of the plaque mass is
separated from junctional epitheliun by a layer
of host leukocytes and the bacteria of this
apical-tooth associated region show an
increased concentration of Gm-ve rods
Dr Saif Khan 2109/10/13
22. Dental Plaque as a Biofilm
• Biofilm is a highly organized structure
• Consists of microcolonies of bacterial cells
randomly distributed in a shaped matrix or
glycocalyx.
• Lower plaque layer are dense in which
microbes are bound together in
polysaccharide matrix with other organic and
imorganic materials
Dr Saif Khan 2209/10/13
23. • On top of lower layer, loose layer can be seen
which can extend into surrounding medium
(for teeth and saliva)
• The fluid layer bordering the biofilm has a
stationary sublayer and a fluid layer in motion
• Nutrient components penetrate this fluid
medium by molecular diffusion
Dr Saif Khan 2309/10/13
24. • The dental plaque biofilm has open fluid filled
channels running across the plaque mass
• Act as primitive “circulating system”
Dr Saif Khan 2409/10/13
25. Intercellular Matrix
• Organic Constituent- Consists of
– Polysacchrides, Proteins, Glycoprotein & Lipid
– Albumin derived from GCF
– Lipid material consists of debris from the membranes
of disrupted bacterial & Host cells and possibly Food
debris
– Glycoprotein from saliva important component of
pellicle
– Polysacchrides produced by bacteria of which
Dextran is most predominant form & play major role
in maintaining integrity of Biofilm
Dr Saif Khan 2509/10/13
26. Inorganic component
• Predominantly Ca and P
• Trace minerals Na, K and F
• Source of inorganic constituent of supragingival
plaque is primarily saliva
• As mineral content increases plaque calcifies to
Calculus
• Inorganic portion of subgingival fluid are derived
from crevicular fluid
• F content of plaque is basically derived from
external sources such as floridinated toothpaste,
rinses, water etc
Dr Saif Khan 2609/10/13
27. Plaque formation at Ultrastructural level
1. Formation of Pellicle
– Thin, saliva derived layer
– Consists of Glycoprotein (mucins), Proline rich protein,
Phosphoproteins (Statherin), Histidine rich
proteins,enzymes
– Forms within seconds of prophylaxis
– Forms by selective adsorption of enviromental
macromolecules
– Mechanism involved in pellicle formation include
Vanderwall forces & Hydrophobic forces
Dr Saif Khan 2709/10/13
30. 2. Initial Adhesion and attachment of bacteria
Phase I : Transport to the surface
•Initial contact of bacterium to tooth surface
•Random contacts through Brownian movement (40μm/hr)
•Through Active bacterial movement
Phase II: Initial Adhesion
•Reversible adhesion
•Interaction b/w bacteria and surface at certain distance (50nm) through
long range and short range forces
•Including Vanderwall attractive and electrostatic repulsive forces
•Gibbs total energy GTOT = GA + GE
•GTOT is a function of separation distance between negatively charged
particle and negatively charged surface in a medium ionic suspension
(saliva)
•For most bacteria reversible binding takes place 5-20 nm from surface
Dr Saif Khan 3009/10/13
31. Schematic representation of interactions involved in
bacterial adhesion to solid substrata
Dr Saif Khan 3109/10/13
32. Phase III: Attachment
•After intial adhesion firm adhesion is established by specific interactions (covalent,ionic or
hydrogen
•Rough surfaces are more conducive for attachment as bacteria are better protected against sheer
force leading change from reversible to irreversible bonding
•The bonding between bacteria and pellicle is mediated by by specific extracellular protein
components
eg; Streptococci (S sangius) early colonizer binds to acidic proline-rich
proteins, also α-amylase and sialic acid
Dr Saif Khan 3209/10/13
33. 3. Colonization and plaque maturation
Primary Colonizers: Streptococci and Actinomycetes
Secondary Colonizers: P intermedia, P loescheii,
Capnocytophaga, F nucleatum, P gingivalis
Dr Saif Khan 3309/10/13
34. All oral bacteria possess surface molecule or
receptor which foster cell to cell interaction
Highly specific stereo chemical interaction of
proteins and carbohydrate molecules located
on bacterial cell surfaces leading to
Coaggregation
Most Co aggregation are among strains of
different genera are mediated by Lectin like
adhesins and inhibited by Lactose and other
galactosides
Dr Saif Khan 3409/10/13
35. Examples of Co-aggregation
Fusobacterium nucleatum with steptocooci
sangius,Prevotella loescheii with A viscosus
Capnocytophaga ochraceus with A viscosus
Intrageneric co-aggregation in streptocooci
Dr Saif Khan 3509/10/13
36. Dr Saif Khan 36
Fusobacterium
nucleatum
S sangius
P loeschii
A viscosus
09/10/13
39. Growth dynamics of Dental Plaque
• First 2-8 hrs, adherent pioneering
streptococci saturate the salivary pellicular
binding sites and cover 3-30% of enamel
surface
• After 1 day the term Biofilm is fully deserved
because organization takes place in it
• After 3 days plaque growth increases at rapid
rate and then slows down
Dr Saif Khan 3909/10/13
40. • There is shift towards more anaerobic and gram-
negative flora, including an influx of Fusobacteria,
filaments, Spiral forms and spirochetes
• In ecological shift within of the biofilm, there is a
transition from the early aerobic environment
characterized by Gm+ve facultative species to a
highly oxygen- deprived environment in which
Gm-ve anaerobic microorganism predominate
Dr Saif Khan 4009/10/13
41. Topography of Supragingival Plaque
• Early plaque formation follow typical topograhic
pattern with initial growth along gingival margin
and interdental space
• Later further there is extension in coronal
direction
• This pattern changes when tooth contains
surface irregularities such as grooves,cracks,
perikymata, or pits
• Surface irregularities can give rise to
“individualized plaque growth pattern
Dr Saif Khan 4109/10/13
42. Surface Microroughness
• Rough intraoral surface (crown,implant
abutments, denture bases)accumulate and
retain more plaque and calculus in terms of
thickness area and colony forming unit
• [Ra=0.2µ] is threshold for surface roughness
above which bacterial adhesion is facilitated
Dr Saif Khan 4209/10/13
43. Individual variables influencing plaque
formation
Heavy(fast) plaque formers
Rapid plaque formers demonstrate higher proportion
of Gm-ve rods (35% vs 17%) in 14-day old plaque
Light (slow) plaque formers
Dr Saif Khan 4309/10/13
44. Intersubject variation in plaque formation can be
explained by factors such as
• Diet
• Food
• Smoking
• Presence of copper amalgam
• Tongue& palate brushing
• Colloid stability of bacteria in the saliva
• Antimicrobial factors present in saliva
• Chemical composition of the Pellicle
• Retention depth of dentogingival area
Dr Saif Khan 4409/10/13
45. Variation within the Dentition
Early plaque formation occurs faster in
•lower jaw compared to upper
•Molar areas
•Buccal tooth surfaces as compared to oral sites
(esp in upper jaw)
•Interdental region compared to buccal or oral
surfaces
Dr Saif Khan 4509/10/13
46. Impact of Gingival inflammation
• Early invivo plaque formation is more rapid
on tooth surfaces facing inflamed gingival
margins than those adjacent to healthy
gingival margins
• Increase in crevicular fluid production
enhances plaque formation
Dr Saif Khan 4609/10/13
47. Impact of Age
Recent studies show that subject’s age does not
influence de novo plaque formation
Dr Saif Khan 4709/10/13
48. Spontaneous tooth cleaning
• Firm attachment between bacteria and
surface this is unlikeky
• Even occlusal part of molars, plaque remains
after chewing fibrous food
• Only negligible differences in plaque extension
could be observed
Dr Saif Khan 4809/10/13
49. De novo subgingival plaque
formation
Recent studies suggest that complex
subgingival microbiota, including most
periopathogens, is established within 1 week
after abutment insertion
Smooth abutments[Ra<0.2µ] were found to
harbour less bacteria than less ones, with a
slightly higher density of coccoids (i.e
nonpathogenic) cell
Dr Saif Khan 4909/10/13
50. Physiological properties of Dental Plaque
The transition from Gm+ve to Gm-ve
microorganism observed in structural
development of plaque is paralled by physiologic
transition in the developing plaque
Early colonizers use oxygen and lower redox
potential of the environment which then favors
growth of anaerobic species
Dr Saif Khan 5009/10/13
51. Early colonizers use sugar as energy source
and saliva as carbon source
Bacteria which predominate in mature plaque
or late colonizers are Asaccharolytic and use
amino acids and small peptides as energy source
Lactate and formate are by products of
metabolism of streptococci and actinomycetes may
be used by other microorganism
Dr Saif Khan 5109/10/13
52. Hemin a breakdown product from host
hemoglobin is important in metabolism of P
gingivalis
Increase in steroid hormone is associated
with increase in proportions of Prevotella
intermedia in subgingival plaque
Dr Saif Khan 5209/10/13
53. Metabolic interaction among different bacteria species found in plaque and
also between host and plaque bacteria
Dr Saif Khan 5309/10/13
54. Ecological plaque Hypothesis
Given by Marsh & Co- Workers in 1990
Total amount of dental Plaque and the
specific microbial composition of plaque
contribute to transition from health to disease
Health –associated dental plaque microflora is
considered to be relatively stable overtime and in
state of dynamic equilibrium or “ microbial
homeostasis ” Dr Saif Khan 5409/10/13
55. Ecological plaque Hypothesis
Change in nutrient status of a periodontal pocket
or
Chemical and physical changes to habitat can
lead over growth of pathogens
Eg: Increase in GCF flow can lead to enrichment of
proteolytic species(periopathogens) by providing
essential nutrients such as heme containing
molecules
Dr Saif Khan 5509/10/13
56. Dr Saif Khan 56
Schematic representation of the ecological
plaque hypothesis in relation to periodontal disease
09/10/13
57. Dr Saif Khan 57
Relationship between the microbial composition of dental plaque in health and
disease.
09/10/13
58. Non- specific plaque hypothesis
Periodontal disease results from elaboration of
noxious products from entire plaque flora
Large amount of plaque produces large amount of
noxious product that would overwhelm host’s
defense
Dr Saif Khan 5809/10/13
59. Dr Saif Khan 59
Control of periodontal disease depend on control
of amount of plaque deposit
The current standard treatment of periodontitis
still focuses on the removal of plaque and its
product founded on non-specific plaque
hypothesis
09/10/13
60. Non-specific plaque hypothesis has been
discarded because
Some individuals with considerable amount of
plaque and calculus as well as gingivitis never
developed destructive periodontitis
Individuals with periodontitis demonstrated
considerable site specificity in pattern of disease
Individuals with very less plaque developed
destructive periodontal disease as in Aggressive
periodontitis
Dr Saif Khan 6009/10/13
61. Specific plaque Hypothesis
States that only certain plaque is pathogenic
And its pathogenecity depends on presence of or
increase in specific microorganism
Dr Saif Khan 6109/10/13
62. 09/10/13 Dr Saif Khan 62
Plaque harboring specific bacterial
pathogen results in periodontal disease
because these organism produce
substance that mediate the destruction
of host tissue
Eg: A actinomycetemcomitans as pathogen in
localized aggressive periodontitis
63. Specific Bacterial behaviour in Biofilm:
Antibiotic resistance
Microorganisms in biofilm are 1000 to 1500
times more resistant to antibiotics than in
their planktonic stage
The mechanism of this increased resistance
differs from species to species, from
antibiotic to antibiotic, and for biofilm
growing in different habitats
Dr Saif Khan 6309/10/13
64. Resistance of bacteria to antibiotics is affected
by their
• Nutritional status
• Growth rate
• Temparature
• pH
• Prior exposure to subeffective concentration
of anti microbial agents
Dr Saif Khan 6409/10/13
65. 09/10/13 Dr Saif Khan 65
Also slower growth of bacterial species in
biofilm is another important mechanism of
antibiotic resistance
Biofilm matrix although not significant barrier
in itself to diffusion of antibiotics but have
certain properties to resist diffusion
Biofilm act as ion-exchange resin removing
antibiotics from solution
66. 09/10/13 Dr Saif Khan 66
Also extracellular enzymes such as β
lactamases, formaldehyde lyase and
formaldehyde dehydrogenase may become
trapped and concentrated in the extracellular
matrix thus inactivating some
antibiotics(especially positive charged
hydrophilic antibiotics)
67. 09/10/13 Dr Saif Khan 67
Some antibiotics such as Macrolide which
are positive charged but hydrophobic
are unaffected by this process
68. 09/10/13 Dr Saif Khan 68
“Super-resistant” bacteria have been identified
within a biofilm and these cells have multidrug-
resistant pump that can extrude antimicrobials
from the cell
69. Quorum Sensing
Bacteria in biofilm communicate with each
other
This involves the regulation of
expression of specific genes through
accumulation of signalling compounds
that mediate intercellular communication
When these signalling compounds reach a
threshold level(quorum cell density) gene
expression is activated
Dr Saif Khan 6909/10/13
70. • Quorum sensing seems to play a role in
expressing genes for antibiotic
resistance and encouraging growth of
beneficial species to the biofilm and
discouraging the growth of competitors
Dr Saif Khan 7009/10/13
71. Schematic representation of the types of interaction
that occur in a microbial community, such as dental
plaque
Dr Saif Khan 7109/10/13
72. Dr Saif Khan 72
High density of bacterial cells in biofilm
facilitates the exchange of genetic
information among cell of the same
species and genera through;
1. Conjugation (sex pilus)
2. Transformation (movement of small pieces of DNA
from enviroment into bacterial chromosome)
3. Plasmid tranfer
4. Transposon transfer (DNA sequence which can
change sequence within the genome)
09/10/13
74. Translocation and Mechanical Debridement
• To reduce chance of intraoral transmission, one
stage, Full mouth disinfection has been
introduced by Leuven group in the 1990s
• This strategy attempts to eradicate, or atleast
suppress, periopathogens in short time not
only from the periodontal pockets, but also from
all their intraoral habitats(mucous membrane,
tongue, and saliva)
Dr Saif Khan 7409/10/13
75. One stage, Full mouth
disinfection
Full mouth scaling and root planning within
24 hrs to reduce number of subgingival
pathogenic organisms
Subgingival irrigation of all pockets with 1%
chlorhexidine gel to kill remaining bacteria
Tongue brushing with an antiseptic to
suppress the bacteria in the niche
Mouth rinsing with antiseptic to reduce the
bacteria in the saliva and on the tonsil
Dr Saif Khan 7509/10/13
76. Benefits of the One stage, Full mouth
disinfection
• Pocket depth reduction
• Gain in clinical attachment level
• Microbiologic shift
Dr Saif Khan 7609/10/13
77. The current concept on etiology of
Periodontitis considers three factors that
determine whether active periodontitis
will occur
1. Susceptible Host
2. Presence of a Pathogenic species
3. Absence or small numbers of beneficial
species
Dr Saif Khan 7709/10/13
79. Role of Beneficial
species
Role of Beneficial
species
Passively
occupying
niches
otherwise
occupied by
pathogenic
bacteria
Passively
occupying
niches
otherwise
occupied by
pathogenic
bacteria
Actively
limiting
pathogens
ability to
adhere to
appropriate
tooth
surface
Actively
limiting
pathogens
ability to
adhere to
appropriate
tooth
surface
Adversely
affecting
the vitality
or growth
of
pathogens
Adversely
affecting
the vitality
or growth
of
pathogens
Affecting
the ability
of
pathogenic
species to
produce
virulence
factor
Affecting
the ability
of
pathogenic
species to
produce
virulence
factor
Degrading
Virulence
factor
produced
by
pathogen
Degrading
Virulence
factor
produced
by
pathogen
Dr Saif Khan 7909/10/13
80. Dr Saif Khan 80
Beneficial species such as S sangius,
Veillonella parvula and C ochreus are
typically found in higher number at
periodontal sites with no attachment loss
where as lower in number where there is
active periodontal destruction
09/10/13
81. Criteria for identification of Periodontal pathogen
Kochs Postulates
Given by Robert Koch as classic criteria by which
microorganims are judged causative
Must be routinely isolated from diseased individual
Must be grown in pure culture in laboratory
Must produce similar disease when inoculated in
susceptible laboratory animal
Must be recovered from lesions in diseased laboratory
animal
Streptococcus mutans has been shown to follow Koch’s
postulate as an etiologic agent of dental caries
Dr Saif Khan 8109/10/13
82. koch’s criteria are difficult to apply in periodontal
disease because of 3 reasons
1. Inability to culture all the microorganism that
have been associated with disease (eg:
spirochetes)
2. The difficulties inherent in defining and
culturing sites of active disease
3. Lack of good animal model for study of
Periodontitis
Dr Saif Khan 8209/10/13
83. Socransky criteria
• Proposed criteria by which periodontal microorganism
may be judged to be potential pathogens
1. Must be associated with disease, as evident by increase
in the number of organisms at diseased sites
2. Must be eliminated or decreased in sites that
demonstrate clinical resolution of disease with
treatment
3. Must demonstrate a host response, in the form of an
alteration in the host cellular or humoral immune
response
4. Must be capable of causing disease in experimental
animal model.
5. Must demonstrate virulence factors responsible for
enabling the microorganism to cause destruction of
periodontal tissue
Dr Saif Khan 8309/10/13
84. Microorganism associated with specific
periodontal disease
Fewer coccal cells and more motile rods and
spirochetes are found in diseased state than
healthy sites by means of phase-contrast or
dark-field microscopy
All most all periodontal pathogens except
Campylobacter rectus are immobile
Bacteria from healthy periodontal sites consists of
gram +ve facultative rods and cocci
Dr Saif Khan 8409/10/13
85. Periodontal Health
Gm+ve facultative species of genera
Streptococcus and Actinomycetes(S sangius, S
mitis, A viscosus, A naeslundi)
Small proportions of Gm-ve speciesa are also
found (P intermedia, F nucleatum,
Capnocytophaga, C ochareus)
Dr Saif Khan 8509/10/13
86. Gingivitis
Micro biota of dental –plaque induced
gingivitis(chronic gingivitis) consists of equal
proportions of
Gm+ve(56%) & Gm-ve(44%) species
Facultative(59%) & anaerobic(51%)
microorganisms
Predominant Gm+ve microorganisms are S
sangius, S mitis, S intermedius, S oralis, A viscosus,
A naeslundii and P micros
Dr Saif Khan 8609/10/13
87. Dr Saif Khan 87
The predominant Gm-ve microorganisms are F
nucleatum, P intermedia, V parvula as well as
Haemophilus, Campylobacter and Capnocytophaga
Pregnancy associated gingivitis is acute inflammation of
gingivae associatedin pregnancy. There is increase in steroid
hormones in crevicular fluid and dramatic increase in
Prevotella intermedia which uses steroid as growth factor
09/10/13
88. Chronic periodontitis
Microscopic examination of plaque from sites
with chronic gingivitis consistently revealed
elevated proportions of spirochetes
Cultivation of plaque microorganisms from sites
chronic periodontitis have reveal high
percentages of anaerobic(90%) and gram
negative (75%) bacterial species
Dr Saif Khan 8809/10/13
89. Dr Saif Khan 89
Bacteria most often cultivated include P.
gingivalis , T. forsythus,,C rectus, E
corrodens, F. nucleatum, A
actinomycetemcomitans, P micros,
Treponema and Eubacterium
C rectus, P gingivalis, P intermedia, F nucleatum &
T forsythia are elevated in active sites09/10/13
90. Dr Saif Khan 90
Detectable levels of P gingivalis, P intermedia,
T forsythia, C rectus and A
actinomycetemcomitans are associated with
disease progression and their elimination by
therapy is associated with improve clinical
outcome
09/10/13
91. Dr Saif Khan 91
Also recent studies have documented
association between chronic periodontitis
and viral microrganisms of Herpes group,
most notably Epstein barr virus-1
(EBV-1) and Human cytomegalovirus
(HCMV) are associated with putative
pathogens P gingivalis, T forsythia, P
intermedia and T denticola
09/10/13
93. Localized Aggressive Periodontitis
A actinomycetemcomitans compose of 90%
of total cultivable microbiota
P gingivalis, E corrodens, C rectus, F nucleatum,
B capillus, Eubacterium brachy, Capnocytophaga
sp and Spirochetes are also found in significant
levels
Herpes viruses, including EBV-1 and HCMV
have been associated with LAP
Dr Saif Khan 9309/10/13
94. Necrotizing Periodontal disease
Microbiologic studies indicate high levels of
Prevotella intermedia and especially
Spirochetes in NUG lesions
Spirochetes penetrate deep into necrotic tissue
and unaffected connective tissue
Dr Saif Khan 9409/10/13
95. Microbial specificity in Periodontitis
• There is no “black-or-white” situation; most
pathogens might be present, but do not necessarily
have to be present for specific form of periodontitis
• Microbial composition can not be used to
differentiate different forms of periodontal
disease
Dr Saif Khan 9509/10/13
96. Dr Saif Khan 96
Most pathogens can also be detected
in healthy subjects with frequencies
ranging from 10% to 85%. This
automatically reduces the specificity
of microbiologic testing in
periodontology
09/10/13
97. Periimplantitis
Inflammatory process affecting the tissue around
an already osseointegrated implant resulting in
loss of supporting bone
Healthy periimplant pockets are characterised by
high proportions of coccoid cells, low
anaerobic/aerobic ratio, low number of gram
anaerobic species and low detection frequency for
periodontal pathogens
Dr Saif Khan 9709/10/13