DEFENCE MECHANISM OF THE GINGIVA SLIDE SHARE

Defence mechanism of gingiva

1. DEFENCE MECHANISM OF
GINGIVA

2. INTRODUCTION
•The gingival tissue is
constantly subjected to
mechanical, chemical &
bacterial aggressions.
•The saliva, the epithelial
surface, initial stages of
inflammatory response &
GCF provide resistance to
these actions.

3. GINGIVAL EPITHELIUM
•The epithelium provides a
physical barrier to infection &
underlying gingival attachment.
•Epithelial cells play an active role
in innate host defence by
responding to bacteria in an
interactive manner that is increased
proliferation. Alteration of cell
signaling events,changes in
differentiation & cell death and
alteration of tissue homeostasis.

4. GINGIVAL EPITHELIUM
•The sulcular epithelium acts as a semi permeable membrane
through which injurious bacterial products pass into the gingiva &
tissue fluid from the gingiva seeps into the sulcus.
•The junctional epithelium is firmly
attached to the tooth surface
forming an epithelial barrier
against plaque bacteria. It allows
access of gingival fluid,
inflammatory cells & components
of the immune host defence to the
gingival margin. The cells of JE
exhibit rapid turn over which
removes the bacteria adhering to
the epithelial cells & also results in
rapid repair of damaged tissue

5. GINGIVAL CREVICULAR FLUID
•Gingival crevicular fluid is a serum transuduate or
inflammatory exudate that derives from the periodontal
tissues and can be collected at the orifice or from
within the gingival crevice.

6. GINGIVAL CREVICULAR FLUID
•In the healthy sulcus amount
of GCF is very small but
during inflammation the fluid
flow increases & its
composition resembles that of
an inflammatory exudate.
•The main route of GCF
diffusion is through the
basement membrane, through
the relatively wide intercellular
spaces of the JE & then into
the sulcus.

7. FUNCTIONS OF GCF
•Cleanses the material from the sulcus
•Contains plasma proteins that may improve
adhesion of the epithelium to the tooth.
•Possesses antimicrobial properties by PMNs,
Lymphocytes & Monocyte macrophages.
•Exert antibody activity to defend the gingiva.
(Ig G)

8. METHODS OF COLLECTION OF
GCF
•Absorbing paper strips & twisted threads placed
around & into the sulcus
•Micropipettes
•Intracrevicular washings

9. COMPOSITION OF GCF
•CELLULAR ELEMENTS:
Bacteria, Desquamated epithelial cells, leucocytes
( PMN,lyphocytes, monocyte macrophages) which
migrate through the sulcular epithelium.
•ELECTROLYTES:
Potassium Sodium & Calcium
•ORGANIC COMPOUNDS :
Carbohydrates & proteins such as Glucose hexosamine
and hexuronic acid.

10. COMPOSITION OF GCF
•METABOLIC & BACTERIAL PRODUCTS
Lactic acid, Urea, Hydroxyproline, Endotoxins,
Cytotoxic substances, Hydrogen Sulphide &
antibacterial factors
•ENZYMES:
Collagenase, Hyaluronidase, Alkaline
phosphatase, acid phosphatase, PGE2, Beta –
glucoronidase.

11. CLINICAL SIGNIFICANCE OF GCF
•CIRCADIAN PERIODICITY :
There is a gradual increase in GCF amount from
6am to 10pm & a decrease afterwards.
•SEX HORMONES:
Female sex hormones increase GCF flow
because they enhance vascular permeability.
Pregnancy, Ovulation & hormonal
contraceptives all increase gingival fluid
production.

12. CLINICAL SIGNIFICANCE OF GCF
•SMOKING :
it produces an immediate transient but marked increase in GCF
flow.
•MECHANICAL STIMULATION :
Chewing & vigorous gingival brushing stimulate the flow of GCF
•PERIODONTAL THERAPY: There is an increase in GCF
production during the healing period after periodontal surgery.
•DRUGS IN GCF :
Such as Tetracycline & Metronidazole have been detected in the
human GCF.

13. CLINICAL SIGNIFICANCE OF GCF
•BIOCHEMICAL MARKERS IN GCF :
Such asAsparatate aminotransferase (AST) ,
Alkaline phosphatase, collagenase PGE2, Beta –
glucoronidase are being used to monitor
periodontal disease activity as advanced
diagnostic aids.

14. SALIVA
Salivary secretions are protective in nature
because they maintain the oral tissues in a
physiologic state.
FUNCTIONS :
•Lubrication – Glycoproteins & mucoids
•Physical protection – Glycoproteins &
mucoids
• Cleansing – the physical flow results in
clearance of debris & bacteria.

15. SALIVA
FUNCTIONS :
•Buffering – Bicarbonate & phosphate (they
neutralise the acids)
•Tooth integrity maintenance- minerals such
as calcium, phosphate & fluorides help in
maturation & remineralisation.Glycoprotein
Pellicle helps in mechanical protection.

16. FUNCTIONS OF SALIVA
•Antibacterial action – IgA prevents bacterial
colonization. Enzymes such as Lysosyme breaks the
bacterial cell walls.Lactoperioxidase results in oxidation
of susceptible bacteria.
•Coagulation factors- such as VIII,IX, X, PTA &
Hegemann Factor.Hasten blood coagulation & protects
wounds from bacterial invasion
•Leucocytes in the saliva are known as
OROGRANULOCYTES & reach the saliva by
migrating through the gingival sulcus.

17. CLINICAL SIGNIFICANCE OF
SALIVA
•In humans an increase in inflammatory gingival
diseases,calculus formation, dental caries & rapid
tooth destruction associated with cervical or
cemental caries is partially a consequence of
decreased salivary gland secretion( Xerostomia)
•CAUSES OF XEROSTOMIA:
Sialolithiasis, Sarcoidosis, Sjogren’s syndrome,
Mikulicz disease, Irradiation,Surgical removal of
salivary glands .

18. LEUCOCYTES IN
DENTOGINGIVAL REGION
•The leucocytes in the gingival sulcus are predominantly
PMN and they appear in small numbers extravascularly
in the connective tissue
adjacent to the bottom of the sulcus from there they
travel across the epithelium to the gingival sulcus where
they are expelled.
•Leucocytes are attracted by different plaque bacteria.
•The majority of these cells are viable and have
phagocytic & killing capacity.

19. LEUCOCYTES IN
DENTOGINGIVAL REGION
•These are also found in saliva & constitute a
major protective mechanism against the
extension of plaque into the gingival sulcus.