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Dr. Khalid AL-Tubaigy
Pellicle
is formed primarily from the selective precipitation of various
components of saliva.

Functions of the pellicle are believed to be:
(1) protect the enamel, 
(2) reduce friction between the teeth 
(3) possibly provide a matrix for remineralization.

Pellicle is formed from salivary proteins that have
apparently involved for this function.
These proteins have many basic groups and consequently
adsorb to the phosphate ions while other acidic proteins
adsorb to calcium ions.

Microorganisms do not attach themselves
directly to the mineralized tooth surface
and the teeth are always covered by an a
cellular proteinaceous film.
The pellicle forms on the “naked” tooth
surface within minutes to hours
•
Salivary glycoprotein 
Carbohydrates 
Lipid 
a lesser extent components 
from the gingival crevicular
fluid
Definition: A gelatinous mass of
bacteria (soft, translucent, and
tenaciously adherent material)
accumulating on the surface of teeth.
Attachment, growth and
reattachment of bacteria to the tooth
surface is a continuous and dynamic
process.
Formation of acquired pellicle and
primary aggregation
Bacteria growth and development
The mature of dental plaque .3
.1
.2
bacteria which form 50-70% of dental
plaque
glycoprotein together with extracellular
polysaccharides form the plaque matrix


• Muco-poly-saccharides such as glucans and
fructans
• Inorganic components
calcium
phosphorus
fluorides
.
Supra gingival plaque
-----dental caries
Sub gingival plaque
-----periodontal diseases
1. Plaque on smooth surface
Plaque adhere to dental surface
Middle layer condensed microbial
layer
(body of plaque)
2. Plaque in pit and fissure
Advanced lesions often have a high proportion of
lactobacilli
dentinal lesions have a diverse micro-flora with many
Gram positive(+), Gram negative(-) bacteria.
Root surface caries was originally associated with
Actinomyces, but recent studies suggest a similar
etiology to enamel caries
Rampant caries and early childhood caries can occur in
xerostomic patients and infants fed with high levels of
sugar in pacifiers (nursing bottle caries) the plaque
contains high levels of mutans streptococci and
lactobacilli.
Pits and Fissures:
Large numbers of MS gram-positive cocci especially S. sanguis
are found in the pits and fissures of newly erupted teeth.
In cross-section, the gross appearance of pit & fissure lesion is an
inverted V with narrow entrance and a progressively wider
area of involvement closer to the DEJ .
Smooth Enamel Surfaces:
Less favorable site for plaque attachment.
Plaque develops near the gingival area or under proximal
contacts.
Lesions have broad area of origin and a conical or pointed
extension toward the DEJ.
Path of ingress of the lesion is roughly parallel to long axes
of
enamel rods in the region.
Cross-section of enamel of the lesion shows V shape with a
wide
area of origin and the apex of the V directed toward the DEJ.
Root Surface:
Cementum is extremely thin and provides little resistance to caries
attack.
Lesions have less well defined margins tend to be U-shaped in
cross-section and progress more rapidly.
In recent years, Prevalence of root caries has significantly
increased
because of the increasing number of older persons who retain
more
teeth experience gingival recession and usually have cariogenic
plaque on the exposed root surfaces.
The time for progression from incipient caries to cavitations
on
smooth surfaces is estimated to be 18 ± 6 months.
Peak rates for the incidence of new lesions occurs 3 years
after eruption of the tooth.
Both poor oral hygiene and frequent exposures to sucrose
containing
food can produce incipient (white spot).
Incipient Smooth-Surface Lesion:
On clean, dry teeth, the earliest evidence of caries is white
spot
(chalky white) .
Incipient caries will partially or totally disappear visually
when
the enamel is hydrated (wet) while hypocalcified enamel is
relatively unaffected by drying and wetting .
Injudicious use of explorer tip can cause actual cavitation for
a previously noncavitated incipient area thus requiring in
most
cases restorative intervention.
Zones of Incipient Lesion :
(a) Intact surface zone
(b) Body of lesion
(c) Dark zone
(d) Translucent zone
Zone 1 Translucent Zone
1. Name refers to its structureless appearance
when perfused with quinoline solution and
examined with polarized light.
2. The deepest zone.
3. Pore volume is 1%.
Zone 2 Dark Zone
1. Does not transmit polarized light.
2. Light blockage is caused by the presence of many
tiny pores too small to absorb quinoline.
3. These smaller air or vapor, filled pores make the
region opaque.
4.Pore volume is 2% - 4% .
5. Size of dark zone is probably an indication of the
amount of remineralization that has recently
occurred.
Zone 3 Body of the Lesion
1.The largest portion.
2. Has the largest pore volume, varying from 5% at
periphery to
25% at the center.
3. Bacteria may be present in this zone if the pore size is
large
enough to permit their entry.
Zone 4 Surface Zone
1. Unaffected by the caries attack.
2. Has lower pore volume than the body of the
lesion
(< 5%) and radiopacity comparable to unaffected
adjacent enamel.
3. Surface of normal enamel is hypermineralized by
contact with saliva and has a greater
concentration of fluoride ion than the
immediately subjacent enamel.
* Pulp-dentin complex reacts to caries attacks by
attempting to initiate remineralization and blocking off the
open tubules.
* These reactions result from odontoblastic activity and
the physical process of demineralization and
remineralization .
* Levels of dentinal reaction to caries :
(1) Reaction to long-term, low-level acid demineralization
associated with a slowly advancing lesion.
(2) Reaction to moderate-intensity attack.
(3) Reaction to severe, rapidly advancing caries
characterized by very high acid levels.
Zone 1 Normal Dentin.
1. The deepest area is normal dentin,
2. No bacteria are in the tubules.
3. Stimulation of dentin (e.g., by osmotic gradient [sucrose or salt],
bur, dragging instrument, or desiccation from heat or air),
produces sharp pain.
Zone 2 Sub-transparent Dentin.
1. Is a zone of demineralization of the inter-tubular dentin .
2. Damage to odontoblastic process is evident.
3. No bacteria .
4. Stimulation of the dentin produces pain, and the dentin is
capable of remineralization.
Zone 3 Transparent Dentin
1. is softer than normal dentin .
2. Stimulation of this region produces pain.
3. No bacteria are present.
4. Dentin is self repaired.
Zone 4 Turbid Dentin
1. filled with bacteria .
2. Collagen in this zone is irreversibly de-natured.
3. Dentin is not self-repaired (not remineralized )
and must be removed before restoration.
Zone 5 Infected Dentin
1. The outermost zone .
2. consists of decomposed dentin that is teeming with
bacteria.
3. No recognizable structure to dentin and collagen
and mineral seem to be absent.
4. Great numbers of bacteria are dispersed in this
granular material.
The possibilities seem to be:
1. The color is exogenous stain absorbed from the
mouth (e.g. from tea, coffee, red wine).
2. comes from pigment-producing bacteria.
3. is the product of a chemical reaction called the
Maillard Reaction.
4. A brown color is produced when protein breaks down
in the presence of sugar .