Pellicle and Dental Plaque
Dr .Huda Y K
P
P
e
e
l
l
l
l
i
i
c
c
l
l
e
e
The pellicle is a thin, bacteria-free layer
covering the teeth, It is formed by the
adsorption of salivary proteins, for
example,
glycoproteins
, which have high
affinity for the mineral in the surface of the
tooth.
The positively charged HAP crystals will
attract negatively charged organic
components from the saliva.
If the pellicle is removed, for example, by the
dentist during a professional cleaning, it
will start forming again within seconds.
The pellicle plays an important role in
protecting the dental hard tissue against
mechanical and chemical damage:
• Mechanically, so it is not worn away, and
• Chemically because the pellicle serves as
a permselective diffusion barrier, limiting
what can pass through it, including plaque
acids.
D
D
E
E
N
N
T
T
A
A
L
L
P
P
L
L
A
A
Q
Q
U
U
E
E
/
/
B
B
I
I
O
O
F
F
I
I
L
L
M
M
• Dental plaque is an adherent deposit of
bacteria and their products, which forms
on all tooth surfaces.
• Plaque is a biofilm.
• Biofilm is defined as a microbiologically derived
community, characterized by cells which are
irreversibly attached to substrate or interface or
with each other, embedded in matrix of
extracellular polymeric substances.
• 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 organized
structure of dental plaque.
• Calculus(Tartar) is hard deposits that form by
mineralization of dental plaque and is generally
covered by a layer of un mineralised plaque.
8
• Materia alba
• Calculus
9
Composition of plaque
Components of Bio lm
•
Water 80%
•
Inorganic Components
•
Organic Components
•
Microorganisms
•
Intermicrobial matrix
20%
Components of Bio lm
Inorganic Components
Calcium, phosphorus and fluoride are more in biofilm than
in saliva.
Organic Components
• Carbohydrates: these are produced by bacterias.
Commonly present carbohydrates are fructans and
glucans.
•Proteins: Proteins are derived from saliva and gingival
sulcus fluid.
• Lipids: they include endotoxins from Gram-negative
bacterias.
Microorganisms
• 70 to 80 % of total solid plaque volume.
• The two most studied microorganisms in
plaque relating to caries disease are:
1. Streptococcus mutans
2. Lactobacillus acidophilus
Intermicrobial Matrix
• The material present between the bacteria in
the dental plaque is called the intermicrobial
matrix.
• Consisting of organic, inorganic materials
and glycoproteins from the saliva
STAGES OF FORMATION IN
DENTAL PLAQUE
The formation of the pellicle on the tooth
surface
Colonization of bacteria
plaque maturation
15
DENTAL PAQUE
STAGES OF FORMATION IN
DENTAL PLAQUE
1. Formation of pellicle
In this stage, di erent bacteria reversibly or
irreversibly attach to tooth surface enamel
pellicle which acts as foundation for
multilayered biofilm.
2. Colonization of bacteria
In this stage, bacteria which attach in to the dental
pellicle, start dividing forming microcolonies. this
bacterial composition further grow into more mature
complex flora
• Primary colonizers: Gram-positive cocci. They
provide new binding sites for adhesion by other
oral bacteria.
• Secondary colonizers: Gram-negative organisms
(anaerobes) .
They do not initially colonize the clean tooth surface
but adhere to bacteria already in the plaque mass.
3. Maturation of biofilm :
In two weeks, the plaque becomes more
mature. As the biofilm matures, spirochetes
start growing into this ,there is site-to-site di
erences in its composition, that is why
caries progress in some sites but not others
in the same mouth.
How the Plaque Causes Harm
• The microorganisms found in plaque are
usually seen in mouth at all times and are
harmless.
• They feed on many of the foods we eat.
• Carbohydrates are their favorite.
• Plaque sticks to the teeth. If not removed
properly by tooth brushing it will build up in
thick layers.
• Those Microorganisms which are nearest to
the tooth convert to anaerobic respiration. In
this stage they produce acids.
Plaque Stagnation Areas
• Pits and Fissures
• Gingival Margins
• Interproximal areas
• Dental appliences
How the Plaque Causes Harm
Being the thick film saliva can not penetrate
and cannot neutralize the acid produced by
bacteria. These acids demineralize the closest
tooth surface. Thus it will lead to dental caries.
How the Plaque Causes Harm
Plaque also causes irritation of gums and leads to
gingivitis and if not removed, further will lead to
periodontitis and tooth loss.
Plaque can also mineralize and become hard called
calculus (tartar) which invites more deposits causing
more gum problems.
How the Plaque Causes Harm
How the Plaque Causes Harm
Testing of Plaque
• Plaque is usually clear and
can not be seen by naked eyes
unless it is colored with a
special dye.
• Dentist can identify plaque
with dental instruments.
• Testing of plaque should be
done after brushing and
flossing to see if any residual
plaque is remaining.
Testing of Plaque
Disclosing agents
Special tablet containing red dye is chewed thoroughly and
mixture of saliva and dye is moved over teeth and gums for
about 30sec.
Mouth is then rinsed. The unremoved plaque gets stained pink
which can be removed later on by brushing.
Control of Plaque
ØSome of the plaque is removed by saliva
and by movement of cheeks and tongue over
the teeth.
ØRegular brushing and flossing everyday (at
least two times) is necessary to remove the
plaque.
ØRegular professional cleaning by a dentist is
the best way to get rid of the plaque and tartar.
Keep Smiling