INCLUDE HISTORY DEFINITION CLASSIFICATION

1. DENTAL
PLAQUE
LET’S LEARN ABOUT DENTAL
PLAQUE AND ITS STRUCTURE!!

2. TABLE OF
CONTENTS
INTRODUCTION
01
CLASSIFICATION
OF VARIOUS
DEPOSITS
04
HISTORY
02
CLASSIFICATION OF
DENTAL PLAQUE
05
DEFINITION
03
COMPOSITION
OF DENTAL
PLAQUE
06
FORMATION OF
DENTAL
PLAQUE
07 MICROSCOPIC
STRUCTURE OF
DENTAL
PLAQUE
08 PLAQUE AS A
BIOFILM
09

3. INTRODUCTION
● Human fetus is sterile.
● Colonization starts at birth.
● Within hours - facultative & aerobic bacteria.
● 2nd day - anaerobic bacteria.
● Within 2 weeks - mature microbiota established in gut.
● After weaning - 104 microorganisms with 400 different type of bacteria.
● There are 10 times more bacteria than human cells.
● Constant renewal microorganisms - Prevents the accumulation of microorganisms.
● Teeth provide hard, non-shedding surfaces - accumulation & metabolism of bacteria
on hard oral surfaces is considered the primary cause of dental caries, gingivitis,
periodontitis and peri-implant infections.
● In the oral cavity, the bacterial deposits have been termed dental plaque or bacterial
plaque.

4. HISTORY
● Buhlmann (1840) - Buhlmann's fibers
● Fignuis (1847) - Brown membrane/ slime coating of denticolae
● Leber and Rottenstein (1867) - Coatings of leptothrix
● J Leon Williams (1897) - Described dental plaque as ‘felt like mass’
● GV Black (1898) - Coined term "gelatinous dental plaque"
● W D Miller (1902) - Bacterial Plaque
● Wild (1941) - Shortened Black Terminology to the term "Plaque"
● Waerhaug (1950) - Described importance of bacterial plaque in the etiology of
periodontal disease
● Loe et al (1965) - Landmark study on plaque, saying that plaque is main etiological agent
in periodontal disease
● Russel (1967) - Epidemiological studies → Positive correlation between amount of
bacterial plaque and the severity of gingivitis
● Costerton (1999) - Evolved Biofilm

5. PLAQUE
Plaque is derived from the French word
“PLAQUER” which means “TO PLATE”

6. WHAT IS DENTAL PLAQUE?
● WHO DEFINITION (1978): plaque is a specific but highly variable structural entity resulting from colonisation of
microorganisms on tooth surfaces, restorations and other parts of oral cavity and consists of salivary
components like mucin, desquamated epithelial cells, debris and microorganisms all embedded in a
gelatinous extracellular matrix.
● GLICKMAN: It is soft amorphous granular deposits which accumulate on surface of teeth, dental restoration
and dental calculus. (Clinical periodontology 3rd ed.)
● WH Boven (1976): Dental plaque is defined clinically as a structured, resilient, yellow-greyish substance that
adheres tenaciously to the intraoral hard surfaces, including removable and fixed restoration. (Carrnaza 10th
ed.)
● Davies et al (1963): defined plaque as a soft concentrated mass containing mainly of large variety of bacteria
together with certain amount of cellular debris which develops within a short time after tooth brushing.
● Schwartz & Massler (1969): Plaque is a dense microbial Layer consisting of coherent mass of filamentous, rod
like and coccoidal microorganisms embedded in an inter microbial matrix which accumulates on tooth surface.

7. DIFFERENCES BETWEEN TOOTH
DEPOSITS
● Dental plaque must be differentiated from other tooth deposits, like materia alba and
calculus.
● Materia Alba refers to soft accumulations of bacteria and tissue cells that lack the
organised structure of dental plaque.
● Calculus is hard deposits that form, by mineralization of dental plaque and is generally
covered by a layer of unmineralised plaque.

8. MATERIA ALBA DENTAL PLAQUE CALCULUS
White cheese like
accumulation
Resilient clear to yellow-
grayish substance
Hard deposit that forms via
the mineralization of dental
plaque
Soft accumulation of
salivary proteins, some
bacteria, many
desquamated epithelial
cells, and occasional
disintegrating food debris
Primarily composed of
bacteria in a matrix of
salivary glycoproteins and
extracellular
polysaccharides
Generally covered by a
layer of unmineralized
dental plaque
Lacks an organized
structure and is therefore
not as complex as dental
plaque
Considered to be a biofilm
Easily displaced with a
water spray
Impossible to remove by
rinsing or with the use of
sprays

9. TOOTH DEPOSIT DESCRIPTION DERIVATION
ACCQUIRED PELLICLE Translucent, homogenous, thin, ultra
structured film covering and adherent to
the surfaces of the teeth, restorations,
calculus, and other surfaces of the oral
cavity
Supra gingival :saliva Sub gingival:GCF
MICORBIAL PLAQUE Dense organized bacterial system
embedded in an inter microbial matrix that
adhere closely to the teeth, calculus, and
other surfaces of the oral cavity
Colonization of oral micro-organisms
MATERIA ALBA Loosely adherent, ultra structured, white or
grayish, white mass of oral debris and
bacteria that lies over bacterial plaque
Vigorous rinsing and water irrigation can
remove materia alba
Incidental accumulation; Microorganism; desquamated
epth. cell; Disintigrated WBC; food debris8
FOOD DEBRIS Unstructured, loosely attached particulate
matter self- cleansing activity of tongue
and saliva and rinsing vigorously remove
debris

10. CLASSIFICATION OF DENTAL PLAQUE
I.GRANTS CLASSIFICATION-ACCORDING TO LOCATION
A. Coronal plaque- Coronal to the gingival margin
B. Gingival plaque- forms on the external surface of the oral
epithelium and attached gingiva
C. Sub gingival plaque- located between the periodontal attachment
and the gingival margin, within the sulcus or pocket.
D. Fissure plaque- develops in pits and fissures
E. Peri-implant plaque.

11. I.GLICKMAN’S CLASSIFICATION-ACCORDING TO
LOCATION
SUPRAGINGIVAL SUBGINGIVAL
FISSURAL
MARGINAL
CORONAL
TISSUE
ATTACHED
UNATTACHED
TOOTH
ASSOCIATED

12. Despite being red, Mars is a
cold place, not hot
The Sun is the star at the
center of the Solar System
STEP 1
STEP 2

13. SUPRAGINGIVAL PLAQUE
A. Coronal plaque, is only
the(tooth surface)
B. Marginal plaque, which
is( associated with the
tooth surface at the
gingival margin)

14. SUBGINGIVAL PLAQUE
TOOTH ATTACHED UNATTACHED TISSUE ATTACHED
Gram positive, few gram
negative rods and cocci
Gram negative, rods,
filaments, spirochetes
Gram negative, rods,
filaments, spirochetes
Does not extednd JE Extend to JE Extend to JE
Calculus formation, root
caries
Gingivitis Gingivitis, periodontitis
May penetrate
cementum
- May penetrate epithilium and
connected tissues

15. CHARACTERISTICS SUPRAGINGIVAL SUBGINGIVAL
LOCATION Coronal MG Apical MG
ORIGIN Salivary Glycoprotein Down growth bacteria from supragingival
plaque
DISTRIBUTION Starts proximal surface and other protected
areas Heaviest collection on areas not
cleaned daily by patient
Cervical third, esp. facial and lingual
Mandibular
molars
Proximal surfaces
Pits and fissures plaque
Shallow pocket
Attached plaque covers calculus
Unattached plaque extends to the
periodontal
attachment
ADHESION Firmly attached to acquired pellicle
Surface bacteria (unattached) loose:
washed away by saliva
Adhere to :-
tooth surface
subgingival pellicle
calculus

16. RETENTION Rough surface teeth restoration, malpositioned
or carious teeth
Pocket hold plaque against tooth and
overhanging margins
SHAPE AND SIZE Friction of tongue lips cheeks;
Thickness: thicker at the cervical end and on
proximal surfaces
Healthy gingival: thin
plaque 15 to 20 cells thick
Chronic gingivitis: thick plaque, 100 to 300 cells
thick
Molded by pocket wall, follows the form created
by subgingival calculus
MICOR-ORGANISM Early plaque:forms Gram positive cocci
Older plaque (3 to 4 days) increased number of
filaments and fusiforms
4 to 9 days undistributed: more complex flora
with rods, filamentous forms
7 to 12 days: vibrios, spirochetes, more gram org
Anaerobic population
Gram-neg, motile
Spirochete and rods
NOURISHMENT Saliva ingested food Tissue fluid (sulcular fluid),
Exudates, leucocytes
STRUCTURE Densely packed Three layers:
1. Tooth attached
2. Unattached
3. Epithelium attached

17. COMPOSITION OF DENTAL PLAQUE
Bacterial
Microorganism
(70%)
Solid (20%-30%)
Intracellular
matrix (20%-
30%)
Non-Bacterial
Organic content
Inorganic content
Dental Plaque

18. >> MICROORGANISM
70 to 80% of total solid plaque volume.
1 gm of plaque contains approximately 2 X 10^11 bacteria.
(Socransky SS, 1953), (Schroeder, De Boever-1970)
BACTERIAL
BACTERIA FACULTIVE ANAEROBIC
Gram positive S.mutans
S.sanguis
A.viscosus
Gram negative A.actinomycetemcomitans
Capnocytophypa sp.
Ekinella corrodens
P.Gingivalis
F.nucleatum
P.intermedia
B.forsythus
C.rectus
Spirochets T.denticola
NON-BACTERIAL
● Viruses
● Yeast
● Protozoa
● Micoplasma

19. >> INTRACELLULAR MATRIX
Accounts for 20% to 30% of the plaque mass
Organic and inorganic material.
Derived from - Saliva, Gingival crevicular fluid and Bacterial products.
ORGANIC CONTENT
LIPIDS
CARBOHYDRATES PROTIENS
INORGANIC CONTENT
CALCIUM
MINERALS PHOSPHORUS
SODIUM
POTASSIUM
FLOURIDE

20. The plaque formation is divided into three phases
I. Pellicle
formation
FORMATION OF DENTAL PLAQUE
II. Initial
colonization of
microorganisms.
III. Secondary
colonization and
maturation of
microbes

21. ● Pellicle formation is the prerequisite for the development of plaque.
● The pellicle is 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.
● Hydrophobic macromolecules adsorb on the tooth surface to form this conditioning film called acquired
pellicle.
● Three types of time-dependent adsorption of salivary proteins take place to progress the pellicle formation
process.
● Salivary proteins, like proline-rich protein-3 (PRP-3), PRP-4 and statherin, get adsorb very fast onto
hydroxyapatite (HAP) while amylase, glycosylated PRP (PRG) and cystatins bind slowly.
● The third type of protein adsorption is noted in PRP-1, PRP-2 and histatins.
● 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.
>> Phase I: Formation of Pellicle on the tooth surface

22. ● Attachment of calculus
● Nidus for bacteria, plaque formation by the adherence of microorganism
● Lubrication, to keep the surface moist and prevent from drying
● Protective, provide barrier against acids thus reducing dental caries attack
>>> Significance of pellicle formation:
>> Phase II: Initial Adhesion/Attachment of bacteria
● Initial Colonization of Microorganisms Early/initial colonizers are Gram-positive facultative microbes, such as
Actinomyces viscosus and S. sanguis.
● Both get attached variably to the pellicle-coated tooth surfaces.
● Some possess specific attachment structures such as extracellular polymeric substances and fimbriae, which
enable them to attach rapidly upon contact.
● There is an interaction of receptors of the dental pellicle and adhesins of the bacterial surface.
● A. viscosus has fimbriae on which protein adhesins bind specifically to proline-rich proteins (PRPs) found in the
dental pellicle.

23. ● Late/secondary colonizers are Gram-negative bacteria (P. intermedia, P. gingivalis, Fusobacterium
nucleatum) 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.
● Coaggregation is the characteristic of various species and genera of plaque microbes to adhere each other.
● F. nucleatum is believed to be important in bridging between primary and secondary colonizers.
● Examples of interaction of secondary colonizers with early colonizers are F. nucleatum with S.
sanguis;Prevotella loescheii with A. viscosus; Capnocytophaga ochraceus with A. viscosus.
● The examples of interaction among secondary colonizers are F. nucleatum with P. gingivalis; F. nucleatum
with Treponema denticola.
>> Phase III: Secondary Colonization and Plaque maturation

24. FLOWCHART: STEPS IN FORMATION OF PLAQUE
Components of saliva GCF functional products and debris
Hydrostatic interactions occur between positively and negatively charged ions
Formation of pellicil on tooth surface
Formation of initial colonizers
Colonization of Pelican with the microorganisms through adhesion
Formation of secondary colonisers
Formation of complex microbial Flora
Coaggregation of microbial Flora
Transition of ecology of biofilm occurs from Gram Positive to Gram Negative microorganisms
Multiplication of attached bacteria
Adhesion of new bacteria
Plaque maturation

25. MICROSCOPIC STRUCTURE OF PLAQUE
◂ Supragingival Plaque:
◂ Corncob structures are common at the surface of the supragingival deposits.
◂ These structures have inner core of rod-shaped bacterial cells (F. nucleatum) and over the
surface of which is attached to the coccal cells (Streptococci or P. gingivalis).
◂ The term corncob was coined by Jones in 1971 because of their resemblance to an ear of corn.
Subgingival Plaque:
● With increasing thickness of plaque, diffusion in and out becomes more and more difficult.
● An oxygen gradient develops as a result of rapid utilization by the superficial bacterial layers
and poor diffusion of oxygen through the matrix.
● Completely anaerobic conditions eventually emerge in the deeper layers of the deposits. This
leads to transition from Gram-positive to Gram-negative microorganisms.
● In the subgingival plaque, test tube brush or bristle brush structures are common.
● These are composed of filamentous bacteria to which Gram-negative rods adhere Tissue-
associate subgingival plaque microorganisms are S. intermedius, S. oralis, P. micros, P.
intermedia, P. gingivalis, T. forsythia and F. nucleatum.

26. METABOLIC INTERACTION
● Metabolic interactions among different bacterial species found in plaque are:
● Synergistic/agonistic interactions:
● Streptococcus and Actinomyces produce lactate and formate as metabolic byproducts which
are used in the metabolism of Veillonella and Campylobacter, respectively.
● Veillonella produces menadione which is used by P. gingivalis and P. intermedia.
● Campylobacter produces protoheme which is used by P. gingivalis.

27. THANKS!