defense mehanism of gingiva dr alaa attia
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dr Alaa Attia Associate prof, periodontology, Umm Alqura Univerisity, Saudi arabia & Al-Azhar University, EgyptTRANSCRIPT
Defense mechanism
of the Gingiva
Associate Professor Dr Alaa Moustafa Attia
In this topic will describe the role of
the following items in defense
mechanism of gingiva:
- Sulcular fluid
- Leukocytes in the Dentogingival
Area
- Saliva
Defense mechanism of the Gingiva
A- Sulcular fluid
Sulcular fluid = Gingival creivicular fluid (GCF)
firstly discovered at 1950s.
In normal gingiva called transudate
In disease gingiva called inflammatory exudates
1- Methods of collection
2- Permeability of junctional and sulcular ep. 3- Amount 4- Composition
5- Cellular and humoral activity in GCF
6- Clinical significance
7- Drugs in gingival crevicular fliud
1- Methods of collection:
- Absorbing paper strips -Twisted threads placed around and into the sulcus. - Micropipettes - Intracrevicular washings.
- Absorbing paper strips
The absorbing paper strips are placed
within the sulcus (intrasulcular method)
or at its entrance (extrasulcular method).
The placement of the filter paper strip in
relation to the sulcus or pocket is
important.
Placement of filter strip in gingival sulcus for
collection of fluid. A, Intrasulcular method.
B and C, Extrasulcular methods.
Absorbing filter paper in
the gingival crevice
-Twisted threads placed around and into the sulcus.
The threads were placed in the gingival
crevice around the tooth, and the amount of
fluid collected was estimated by weighing the
sample thread.
Threads in and around the
gingival sulcus
- Micropipettes Micropipettes permits the collection of
fluid by capillarity. Capillary tubes of
standardized length and diameter are placed
in the pocket, and their content is later
centrifuged and analyzed
-Intracrevicular washings
Crevicular washings can be used to study
GCF from clinically normal gingiva. By
using an appliance consisting of a hard
acrylic plate covering the maxilla with soft
borders and a groove following the gingival
margins, it is attached to collecting tube.
The washings are obtained by rinsing the
crevicular areas from one side to the other,
using a peristaltic pump.
2- Permeability of junctional and sulcular
epithelium. Substances shown to penetrate the sulcular
epithelium as albumin, endotoxin, histamine,
phenytoin, peroxidase.
Permeability to substances with a molecular weight
of up to 1000 kD.
Mechanisms of penetration through an intact
epithelium by intercellular movement of molecules
and ions along intercellular spaces not traverse the
cell membranes.
3- Amount
An electronic method has been devised for
measuring the fluid collected on a
Periopaper by using an electronic device
called Periotron.
The wetness of the paper strip affects the
flow of an electronic current and gives a
digital readout.
GCF amount very small about
- 0.1 mg - 0.5 – 1.5 µl (microliter)
Electronic device (periotron 8000) for
measuring the amount of fluid collected
on filter paper.
4- Composition
A- Cellular components:
1- Desquamated epithelial cells.
2- Leukocytes e.g. PMNs
3- Microorganisms
B- Non cellular components:
1- Immunoglobins e.g. IgA.
2- Complements
2- Serum protiens, cytokines
3- antimicrobial lysosomal enzyems
4- Elyctrolytes e.g. Ca, PO4, Na and others.
5- Cellular and humoral activity in GCF
Show a humoral and cellular responses
During health and increased in disease
Humoral response: e.g.
- immunoglubins - complements,
Cellular response: e.g.
- PMNs and monocytes/macrophages
- cytokines, inflammatory mediators
6- Clinical Significance
Amount of GCF is greater during inflammation,
sometimes proportional to the severity of
inflammation.
Circadian Periodicity: A gradual increase in GCF amount from 6 AM to
10 PM and a decrease afterward.
Sex Hormones Female sex hormones increase GCF flow, probably
because they enhance vascular permeability.
Pregnancy, ovulation, and hormonal contraceptives
all increase gingival fluid production.
Mechanical Stimulation
Chewing and vigorous gingival brushing stimulate
the flow of GCF. Even the minor stimuli
represented by intrasulcular placement of paper
strips increases the production of fluid.
Smoking
Smoking produces an immediate transient but
marked increase in GCF flow.
Periodontal Therapy
There is an increase in GCF production during the
healing period after periodontal surgery.
7- Drugs in Gingival Crevicular Fluid
Drugs that are excreted through the GCF may
introduce advantages in periodontal therapy.
Drugs: as some antibiotics
- Tetracyclines
- Metronidazole
B- Leukocytes in the Dentogingival
Area
Leukocytes are present in sulci even when
histologic sections of adjacent tissue are free of
inflammatory infiltrate.
Leuckocytes from clinically healthy human
gingival sulci have shown 91.2% to 91.5% PMNs
and 8.5% to 8.8% mononuclear cells
Cells were identified as 58% B lymphocytes,
24% T lymphocytes, and 18% mononuclear
phagocytes.
The ratio of T lymphocytes to B lymphocytes
was found to be reversed from the normal ratio of
about 3 : 1 found in peripheral blood to about 1 : 3
in GCF.
Therefore leukocytes constitute a major protective
mechanism against the extension of plaque into the
gingival sulcus.
C - Saliva Salivary secretions are protective in nature
because they maintain the oral tissues in a
physiologic state.
By the following:
1- Lubrication 2- Physical protection
3- Cleansing 4- Buffering
5- Tooth integrity maintenance
6- Antibacterial action
Probable Mechanism Salivary
Components Function
Coating similar to gastric
mucin
Glycoproteins,
mucoids
Lubrication
Coating similar to gastric
mucin
Glycoproteins,
mucoids
Physical
protection
Clearance of debris and
bacteria
Physical flow Cleansing
Antacids Bicarbonate
and phosphate
Buffering
Function of Saliva
Probable Mechanism Salivary
Components
Function
- Maturation,
remineralization
- Mechanical protection
- Minerals
- Glycoproteins -
Mucoids
Tooth
integrity
maintenance
- Control of bacterial
colonization
Immunoglobulin A
Antibacterial
action
- Breaks bacterial cell
walls
Lysozyme
- Oxidation of
susceptible bacteria
Lactoperoxidase
Function of Saliva