P1-PERIO SAS 6 - DENTAL PLAQUE

proline-rich protein-3 (PRP-3)

PRP-4

statherin

3 Salivary proteins that get adsorb very fast onto

hydroxyapatite (HAP) under pellicle formation

Dental plaque

Is a biofilm with an intercellular matrix consisting primarily of proliferating microorganisms, along with a

scattering of epithelial cells, leukocytes and macrophages that adheres tenaciously to the tooth surfaces or

other hard surfaces in the oral cavity, including removable and fixed restorations.

amylase, glycosylated PRP (PRG) and cystatins

under pellicle formation, these three bind slowly

Dental plaque

It contains areas of high and

low bacterial biomass interlaced with acqueous channels of different sizes, which are the nutrient channels for

bacterial colonization. The intercellular matrix forms a hydrated gel in which bacteria can survive and

proliferate. Hence, biofilm adheres firmly to the tooth surface and is resistant to mechanical removal, as well as

antibiotics.

PRP-1

PRP-2

histatins

The third type of

protein adsorption is noted in

Subgingival

Supragingival

Based on its relationship to the gingival margin, plaque is differentiated into two categories:

pellicle formation

It is a two-step process with a rapid adsorption

involving the direct binding of proteins to HAP followed by a slow adsorption with protein-protein interactions.

This pellicle then alters the charge and free energy of the tooth surface, which in turn increases the efficiency

of bacterial adhesion

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Coronal plague, which is in contact with only the tooth surface, and Marginal plaque, which is associated

with the tooth surface at the gingival margin

Supragingival plaque is further differentiated into:

Coronal plague, which is in ________________, and Marginal plaque, which is associated

with the tooth surface at the _______________

Initial adhesion and attachment of bacteria

initial adhesion of bacteria by some short-range forces-van der waals attractive forces, electrostatic

repulsive forces, all these combined give a total long-range interaction.

*Attached plaque

(can be tooth, epithelium and/or connective tissue associated)

*Unattached subgingival plaque

Subgingival plaque can be further differentiated into:

fimbriae

bacteria connect to the pellicle and

each other with hundreds of hairlike structures called

Supragingival plaque

It can be detected clinically only after it has reached a certain thickness. Small amounts of plaque can be visualized by using disclosing agents. The rate of formation and location of plaque vary among individuals and it's influenced by diet, age, salivary factors, oral

hygiene, tooth alignment, systemic diseases and host factors.

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Actinomyces viscosus

S.

sanguis.

Early/initial colonizers are Gram-positive facultative microbes, such as _________ and ________ Both get attached variably to the pellicle-coated tooth surfaces.

grey to yellowish-grey to yellow

The color of supragingival plaque varies from ______ to ____________ to _________.

extracellular polymeric substances

fimbriae

these are specific attachment structures which enable the bacteria to attach rapidly upon contact

disclosing agents

Small amounts of plaque can be visualized by using ______________

proline-rich proteins

A viscosus has fimbriae on which protein adhesins bind specifically to ________ (PRPs) found in the

dental pellicle

Subgingival plaque

It is usually thin, contained within the gingival sulci or periodontal pocket and thus cannot be detected by direct

observation. Its presence can be identified only by running the end of a probe around gingival margin.

Colonization and plaque maturation

-when the bacteria are now firmly attached to the pellicle, by the process of coadhesion, the primary

colonizing bacteria provide new receptors into which other type of bacteria can attach.

-they start to grow and form into clusters, and then they mature.

running the end of a probe around the gingival margin

subgingival plaque can be identified only by?

P. intermedia

P. gingivalis

Fusobacterium nucleatum

Late/secondary colonizers are Gram-negative bacteria which do not initially colonize clean or pellicle-coated tooth surfaces but may get attach to early colonizers or among themselves by the process called coaggregation.

Name the 3 gram-negative bacteria.

Tooth-associated subgingival Plaque

The structure is similar to the supragingival plaque. The flora is dominated by Gram-positive cocci, and rods.

This flora is associated with calculus formation, root caries and root resorption.

Coaggregation

is the characteristic of

various species and genera of plaque microbes to adhere each other

gram-positive cocci

the tooth-associated subgingival plaque's flora is dominated by?

F. nucleatum

is believed to be important in bridging between primary and secondary colonizers.

Supragingival plaque

50% Matrix

F. nucleatum with S. sanguis

Prevotella loescheii with A. viscosus

Capnocytophaga

ochraceus with A. viscosus

Examples of interaction of secondary colonizers with

early colonizers are (3)

Subgingival plaque

Little or no matrix

F. nucleatum with P.

gingivalis

F. nucleatum with Treponema denticola

The examples of interaction among secondary colonizers are

Supragingival plaque

Mostly Gram-positive

a. Growth via adhesion of new bacteria

b. Growth via multiplication of attached bacteria.

Dental plaque growth depends on:

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Subgingival plaque

Mostly Gram-negative

supragingival plaque

It is usually adherent to the tooth surfaces. It contains gram-positive cocci and gram-negative rods and

filaments.

Supragingival plaque

Few motile bacteria

corncob

The morphologic arrangement of the flora in supragingival plaque described as "__________"

formations, characterized by central core consisting of rod-shaped bacterial cells

Subgingival plaque

Motile bacteria is common

rod-shaped cells

Fusobacterium nucleatum and coccal cells

Supragingival plaque

they are Aerobic unless thick

large filaments,Spirochetes

The subgingival plaque differs from supragingival plaque, in that it contains many ______________

with flagella and is rich in ____________.

Subgingival plaque

there are highly anaerobic areas present

test tube-brush

Tooth-associated plaque is similar to supragingival plaque; whereas tissue-associated plaque is covered with flagellated bacteria without a well-defined extracellular matrix and numerous bristle - brush formations. This arrangement is also called as "_________" formation characterized by large filaments that forms the long axis; and short filaments or gram-negative rods embedded in amorphous matrix.

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Supragingival plaque

Metabolism: Predominantly carbohydrates

gingival health

The microbial aggregations on the tooth surface if prevented from maturing may become compatible

with _____________

Subgingival plaque

Metabolism: Predominantly proteins

TRUE THE RAIN

Supragingival plaque if allowed to grow and mature, may induce gingivitis and can

lead to the formation of a microenvironment that permits the development of subgingival plaque.

Therefore, surpragingival plaque strongly influences the growth, accumulation and pathologic potential

of subgingival plaque, especially in the early stages of gingivitis and periodontitis.

Gram-positive and Gram-negative

bacteria

these predominates Epithelium-associated plaque

enlarged gingiva

In association with the presence of supragingival plaque, there are inflammatory changes that modify the

anatomic relationships of the gingival margin and tooth surface. This result in _________ , which

increases the space for bacterial colonization and also protects bacteria from normal cleansing mechanisms.

tooth-associated subgingival plaque

type of subgingival plaque that does not extend to junctional epithelium

gingival crevicular fluid

bacteria derive their nutrients from

Epithelium-associated subgingival plaque

type of subgingival plaque that extends to junctional epithelium

Cuticle

Electron microscopic studies have demonstrated the existence of an organic material called _______

between the root surfaces and subgingival plaque.

It is covered by a dense layer of microorganisms and is

believed to be a remnant or secretory product of the junctional epithelial cells.

tooth-associated subgingival plaque

type of subgingival plaque that may penetrate cementum

-Lipopolysaccharides (LPS)

-Exotoxin

-Enzyme agents

Bacteria have several virulence factors that allow them to colonize,invade and damage the tissues of the periodontium:

​

Epithelium-associated subgingival Plaque

type of subgingival plaque that may penetrate epithelium and connective tissue

Lipopolysaccharides (LPS)

it also known as endotoxins which is a major component of the cell walls of

the gram-negative bacteria

Tooth-associated subgingival plaque

they are associated with calculus formation and root caries

Exotoxin

they are harmful proteins released by bacteria that are able to destroy the leukocytes in the

sulcus or pocket

Epithelium-associated subgingival plaque

they are associated with gingivitis and

periodontitis.

Enzyme agents

they are released by bacteria that are destructive to host's cells

free floating, unattached bacteria

bacteria in unattached subgingival plaque are __________, ___________

-Nonspecific Plaque Hypothesis

-Specific Plaque Hypothesis

-Ecologic Plaque Hypothesis

Theories on Microbial Specificity of Periodontal Diseases:

unattached subgingival plaque

bacteria within the pocket environment are not subject to the mechanical forces

(saliva, tongue, mastication, toothbrushing) that tend to dislodge bacteria from supragingival tooth

surfaces. Thus, attachment to the tooth surface is not as vital to subgingival bacteria and many

bacteria are completely unattached to the biofilm matrix.

Nonspecific Plaque Hypothesis

-theorized in mid 1900s

-postulates that periodontal diseases are a result from an accumulation of plaque over time which

eventually results to diminished host response and increased host susceptibility with age

-maintains that periodontal disease results from the elaboration of noxious products by the

entire plaque flora

unattached subgingival plaque

the bottom of the sulcus or pocket has unorganized gram-negative rods and spirochetes

separated from the epithelium by a layer of leukocytes.

Specific Plaque Hypothesis

- underlines the importance of the qualitative composition of the resident microbiota.

- the pathogenicity of dental plaque depends on the presence of or an increase in specific

microorganisms.

- encapsulates that plaque that harbors specific bacterial pathogens may provoke periodontal

disease because key organisms produce substances that mediate the destruction of host tissues.

- the association of specific bacterial species with disease came about during the early 1960s, when the

microscopic examination of plaque revealed that different bacterial morphotypes

were found in healthy versus periodontally diseased sites.

Epithelium-Attached Plaque

type of attached plaque which bacteria are attached to the epithelium of the pocket wall

Specific Plaque Hypothesis

- at about the same time, major advances were made in the techniques used to isolate and

identify periodontal microorganisms.

- included improvements in procedures to sample subgingival plaque, in the handling

of samples to prevent killing the bacteria, and in the media used to grow the bacteria

in the laboratory.

Epithelium-Attached Plaque

>the layers closest to the soft tissue wall contain large numbers of motile gram-negative bacteria

and spirochetes.

>bacteria can invade the gingival connective tissue and be found within the periodontal connective

tissues and on the alveolar bone.

​

A. actinomycetemcomitans

acceptance of the specific plaque hypothesis was spurred by the recognition of ____________ as

a pathogen in localized aggressive periodontitis.

Epithelium-Attached Plaque

research suggests that this type of plaque is the most detrimental to the periodontal structures.

Ecologic Plaque Hypothesis

developed by Marsh and coworkers during the 1990s as an attempt to unify the existing theories regarding the role of dental plaque in oral disease

tooth-associated subgingival plaque

most important in calculus formation, root caries and slowly

progressive periodontal destruction,

Ecologic Plaque Hypothesis

- proposed that both the total amount of dental plaque and the specific microbial composition of plaque may

contribute to the transition from health to disease.

- the health-associated dental plaque microbiota is considered to be relatively stable over time and in a state of

dynamic equilibrium or "microbial homeostasis."

- the host controls subgingival plaque to some extent by a tempered immune response and low levels of

gingival crevicular fluid flow.

unattached bacterial component

it is associated with rapid

periodontal destruction.

Ecologic Plaque Hypothesis

perturbations to the host response may be brought about by an excessive accumulation of nonspecific dental

plaque, by plaque-independent host factors, like

- the onset of an immune disorder, changes in hormonal balance [e.g., during

pregnancy]), or

- by environmental factors (e.g., smoking, diet).

- changes in the host status, such as inflammation, tissue degradation, and/or high gingival

crevicular fluid flow, may lead to a shift in the microbial population in plaque.

-70 to 80

-250 million bacteria

Bacteria make up approximately _____ to _____ percent of total material. One mg of dental plaque is estimated to

contain _______________ bacteria

Dysbiosis

As a result of microenvironmental changes, the number of beneficial species may

decrease, whereas the number of potentially pathogenic species increases.

-this gradual shift in the entire microbial community is known as ____________

-mycoplasma

-fungi

-protozoa

-viruses

Other than bacteria,___________ ,________ ,________ and ________ may be present.

Keystone Pathogen Hypothesis,Polymicrobial Synergy and Dysbiosis Model

-indicates that certain low-abundance microbial pathogens can orchestrate inflammatory disease by remodelling a normally benign microbiota into dysbiotic one.

-It has been shown that P.gingivalis even when present in less than 0.1% of the total microbiota developed periodontal bone loss in an experiment done on specific pathogen free- mice exposed to P.gingivalis

inter-microbial/cellular matrix

The material among the bacteria in dental plaque is termed as ______________. It contains

organic and inorganic portions.

keystone

P.gingivalis was labeled a "__________ " pathogen,this means that it is an organism that is central to the disease

process,even when it is a relatively low abundance.

-(fructans)

-(dextran)

The organic matrix is composed of protein polysaccharide complex produced

by microorganisms, Carbohydrates in the form of levans (________) provides mainly energy while glucans

(_________) provide not only energy, but also act as the organic skeleton of plaque.

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a. Physical nature of plaque.

b. Invasion of tissues by bacteria.

c. Release of toxic and inflammatory substances.

d. Role of bacterial specificity.

The following are the possible pathogenic mechanisms by which the plaque microorganisms can cause

periodontal disease.

​

-galactose

-rhamnose

Other carbohydrates present in the organic matrix of are _________

and ________ .

plaque bacteria

It is well accepted that a ___________ is the primary etiologic agent in periodontal disease.

Glycoproteins

these proteins provide the protein components and small amounts of lipids are also

present.

400 different specices

Bacteria are

seen in the oral cavity from birth to death. It is estimated that about ________ different species are capable of

colonizing in the mouth.

Inorganic components

components of inter-cellular matrix of dental plaque that include, primarily calcium, phosphorus with small amounts of magnesium,

potassium and sodium.

about 10³ , greater than 10⁸

only 30

Counts in subgingival sites range from about _______ in healthy sulci to greater than _____

in

deep periodontal pockets. It has not been possible to identify and study all the organisms present in the

bacterial plaque, of nearly 400 species; only ______ of them are considered to be periodontopathic.

1. Pellicle formation

2. Initial adhesion and attachment of bacteria

3. Colonization and plaque maturation

3 major phases of dental plaque formation

Socransky

(1977)

Who and when was the following criteria for indentifying the possible causative organisms in periodontal

diseases proposed?

1. The number of etiologic organisms in the diseased site must be increased and conversely the number

of organisms must be reduced or absent in healthy sites.

2. If the etiologic organisms is eliminated or suppressed, the disease should stop.

3. Presence of specific antibodies to those microorganisms.

4. Presence of virulence factors associated with certain microorganisms (e.g. toxins, enzymes, etc.).

5. In vitro or animal experiments should be able to demonstrate the human disease process.

pellicle formation

nanoseconds after toothbrushing a thin coating of salivary proteins attach or covers the tooth surface

Koch's

Whose postulates, generally used to identify the periodonto-pathogenecity of a microorganism, are not applicable in

periodontal diseases, as more than one organism is involved in periodontal diseases?

pellicle formation

> it is made up of glycoprotein from the saliva to protect the enamel from acidic environment,

>however, it acts also as a double sided adhesive tape, adhering to the tooth surface on one side and

providing a sticky surface on the other side that facilitates attachment of bacteria to the tooth surface.

pellicle formation

the prerequisite for the development of plaque.

pellicle

composed of a

variety of salivary glycoproteins (mucins) that are derived from saliva, crevicular fluid, bacterial and host tissue

cells. Van der waal forces, electrostatic forces and hydrophobic forces play crucial role in pellicle formation.

acquired pellicle

Hydrophobic macromolecules adsorb on the tooth surface to form this conditioning film called