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