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DEFENCE MECHANISM
OF GINGIVA
Achi joshi
MDS II
CONTENTS
1. INTRODUCTION
2. GINGIVAL CREVICULAR FLUID
1. Introduction
2. Formation
3. Functions
4. Method of collection
5....
INTRODUCTION
DEFENSE
MECHANISM
OF GINGIVA
EPITHELIAL
SURFACE
SALIVA
GCF
CONNECTIVE
TISSUE
GINGIVAL CREVICE FLUID
GCF is an altered serum transudate found in the gingival sulcus.
Genco
• Gingival crevice fluid (GC...
HISTORY
• GCF , its composition and possible role in oral defense mechanisms were
elucidated by the pioneering work of Wae...
• Löe et al. contributed to the use of GCF as an indicator of periodontal
diseases (Periodontics 1965)
• Egelberg continue...
FORMATION
• The initial investigations of GCF by Brill
and Krasse and Egelberg relate its
formation to the inflammatory
ch...
• Brill and Krasse (1959) introduced filter paper into the gingival sulci of dogs
previously injected intramuscularly with...
PERMEABILITY OF THE JUNCTIONAL
EPITHELIUM
• Permeable to substances with a molecular weight upto 1000kD
• Albumin
• Endoto...
• Alfano (1974) –hypothesis – flow of gingival fluid might be osmotically
mediated
• Pashley (1976) developed the concept,...
EXUDATE V/S TRANSUDATE
Mathematical model of Pashley, illustrated within the gingival
crevice. Cross-section of two capill...
• GCF protein concentration suggested that inflamed gingivae had a protein
concentration similar to that of serum.
• Most p...
FUNCTION
1. It washes the crevice carrying out shed epithelial cells, leukocytes and
bacterias and debris.
2. It contains ...
METHOD OF COLLECTION
Gingival
washing
methods
Capillary tubing
or
micropipettes
Absorbent filter
paper strips
GINGIVAL WASHING METHODS
In this technique the gingival crevice is perfused with an isotonic solution of
fixed volume. The...
SEMIQUANTITATIVE SKAPSKI AND
LEHNER (1976)
• Useful for studying the number and
functional state of cells and bacteria
fro...
• Proposed by Takamori(1963) and Oppenheim (1970)
• Based on use individual acrylic appliances.
• It involved the construc...
CAPILLARY TUBING OR
MICROPIPETTES
Capillary tubing of known
diameter is placed at the
entrance of the crevice and the
flui...
ABSORBING PAPER STRIPS
• Used in 2 different ways
• Intracrevicular
• Brill (1962)
• End of strips inserted into the
sulcu...
EVALUATION OF THE FLUID COLLECTED
• The amount of GCF collected is extremely small.
• Measurements performed by Cimasoni s...
1.Direct viewing or staining
• Under a microscope fitted with a graticule for determining the wetted area
2. Stain the str...
3. Weighing the strip
• Weinstein et al (1967) inserted preweighed twisted thread into the gingival
crevice ,weighed the s...
PERIOTRON
• An electronic measuring device which allows accurate determination
of the GCF volume and subsequent laboratory...
• If a dry strip is placed between the ‘jaws’, the capacitance is translated
via the electrical circuitry and registers ‘z...
MEASURES SHOWING PERIOTRON INDICES IN RESPECT TO GINGIVAL DISEASES
Periotron
Reading
Level of Gingival
Inflammation
Gingiv...
COMPOSITION
CELLULAR ELEMENTS
• Originate from blood , host
tissue and subgingival plaque,
Bacteria from adjacent plaque
mass, desquam...
• Bacteria with in bacterial plaque
• Microscopic observations
• Some bacteria free float in GCF
• Attached to host cells
...
• Leukocytes – in 1960 Sharry and Krasse determined that 47% of cells
obtained from gingival sulcus are leukocytes
• 95- 9...
ELECTROLYTES
• Sodium
• 207-222 mEq/l
• Potassium
• Exceeds that of serum
• 69mEq/l
• Fluoride
• Other ions
• Calcium , ma...
ORGANIC COMPOUNDS1. Carbohydrates
• Glucose, hexosamine and hexuronic acid
• Glucose 3-6 times that of serum
2. Proteins
•...
METABOLIC AND BACTERIAL
PRODUCTS
• Lactic acid
• Hydroxyproline – breakdown of collagen
• Prostaglandins – PgE2
• Urea
• E...
ENZYMES
• Acid phosphatase
• Connective tissue catabolism
• Attack teichoic acid –one of the components of bacterial cell ...
• Lysozyme
• Hydrolyses β-1,4 – glycosidic bonds of peptidoglycans of bacterial cell wall
• Increased in areas of increase...
GCF FLOW
• It is the process of fluid moving into and out of the gingival crevice or pocket
• Shallow pockets – 3 to 8µl/h...
Isolation effect
• Substances from outside do not penetrate the sulcus easily
• GCF is relatively isolated from saliva--Sa...
CLINICAL SIGNIFICANCE
• Circadian periodicity
• Greater in the evening and minimal in the morning –Bissada et al (1967)
• ...
• Gingival fluid as a sign of subclinical inflammation
• Flow from crevice was demonstrated before clinical gingivitis was...
• GCF and diabetes
• β glucouronidase – higher in diabeteics with poorer metabolic control
• β glucouronidase is a predict...
SALIVA
• Saliva is clear, tasteless, odourless slightly acidic (ph6.8) viscid fluid,
consisting of secretions from the par...
SALIVA
WATER (99.5%) SOLIDS (0.5%)
ORGANIC (0.3%) INORGANIC (0.3%)
GAMMA-GLOBULIN CATIONS ANIONS
PTYLIN SODIUM CHLORINE
MU...
FUNCTIONS OF SALIVA
1. Fluid flow helps to remove bacteria and food debris.
2. Bio-carbonates and phosphate buffer the bac...
ROLE OF SALIVA IN DEFENCE OF GINGIVA
• Saliva exerts a major influence on plaque initiation, maturation and metabolism.
• ...
1. Antibacterial factors
Saliva contains lysozymes, myeloperoxidase, lactoperoxidase, glucoproteins, mucins
& antibodies e...
(c) Myeloperoxidase: enzyme released by leucocytes and is bactericidal for
actinobacillus.
(d) Glycoproteins & mucin: It f...
2. Salivary Antibodies:
1) Saliva IgA, IgG and IgM antibodies.
2) IgA Immunoglobulin found in Saliva.
IgA
• The predominan...
IgG
• Salivary IgG is primarily derived from serum via GCF and is present in low
concentrations.
• Consequently, the IgG c...
• Proteolytic enzymes in the saliva are generated by both the host and oral
bacteria. These enzymes have been recognized a...
• The enzymes normally found in the saliva are derived from the salivary glands, bacteria,
leukocytes, oral tissues,and in...
2. Buffers & coagulation factor
• Salivary buffer bicarbonate – carbonic acid system maintains the physiologic pH of
oral ...
• Living PMNs in saliva are referred to as orogranulocytes, and their rate of
migration into the oral cavity is termed the...
INTRODUCTION
DEFENSE
MECHANISM
OF GINGIVA
EPITHELIAL
SURFACE
SALIVA
GCF
CONNECTIVE
TISSUE
EPITHELIUM
EPITHELIAL BARRIER
• When active disease is present, the
epithelial barrier function fails , results in
bacterial invasion...
Now, it is well established that while the epithelial compartment does
provide a physical barrier to infection, it also ha...
FEATURES OF EPITHELIUM
Architectural integrity
1. Cell–cell attachments
• Desmosome , Adherent
junctions, Tight junctions,...
GINGIVAL EPITHELIAL Cell types
Keratinocytes
Langerhans cell
immunity )
Melanocyte
to make & transfer pigment
Merkel cell
...
EPITHELIUM :BARRIER FUNCTION
1. KERATINOCYTE FORMATION
3. CELL JUNCTIONS
2. LANGERHANS CELLS
58
1. Cell–cell attachments and the overall integrity of the tissue as well as
the process of differentiation (keratinization...
Keratinocyte formation
• Following cell division in the
basal layer and the resultant
birth of a new keratinocyte,
about 3...
They are found in oral epithelium & in smaller amounts in sulcular epithelium & are
absent from JE
They are characterized ...
UNDER ELECTRON
MICROSCOPE
Basement
membrane
Lamina Lucida (400 Å – wide) is in
immediate contact with the
epithelial cells...
DESMOSOMES
• Play a decisive role in the firm attachment
of the cells to the internal basal lamina on
the tooth surface.
•...
• Desmosomes have a typical structure consisting of
two dense attachment plaques into which
tonofibrils insert and an inte...
ZONA OCCLUDENS (TIGHT JUNCTIONS)
• Membranes of the adjoining cells
fuse and allow ions & small molecules
to pass from one...
• FUNCTIONS:
HOLDS CELLS TOGETHER
BLOCK MOVEMENT OF INTERGRAL MEMBRANE PROTEIN
ZONA ADHERENS (GAP JUNCTIONS )
-
• Intercellular space narrows to 2 – 3 nm.
• Transmembrane proteins (connexin) in
adjacen...
JUNCTIONAL EPITHELIUM
• The junctional epithelium consists of a collar like band of stratified squamous
non-keratinizing e...
Junctional
Epithelium
internal basal lamina
to tooth surface
(epithelial attachment)
external basal lamina.
to gingival co...
JE
• The basal cells and the adjacent 1 to 2 suprabasal cell
layers are cuboidal to slightly spindle-shaped.
• All remaini...
JE
• Basal lamina of the junctional epithelium resembles that of endothelial and epithelial
cells in its laminin content
•...
76
WIDE INTERCELLULAR SPACE
MAY BE A DOUBLE ENDED SWORD
widened spaces ALLOW the
transmigration of GC fluid
and leukocytes...
77
JE : ROLE IN DEFENCE
• In contrast to most other epithelia, there is no keratinizing epithelial cell layer at
the free ...
78
ATTACHMENT APPARATUS
• consists of hemidesmosomes at the
plasma membrane of the cells
directly attached to the tooth (D...
79
• DAT cell shows the structural and molecular composition of the
epithelial attachment apparatus (EAA).
• The hemidesmo...
TURNOVER OF JUNCTIONAL
EPITHELIAL CELLS
• Previously it was thought that only epithelial cells facing the external basal
l...
The mechanism of DAT cell turnover is not fully
understood. Considering the fact that the DAT cells
are able to divide and...
83JE:ROLE IN ANTIMICROBIAL DEFENCE
In the coronal part of the JE quick cell exfoliation
1. (A) because of rapid cell divis...
84
IMPORTANT MOLECULES IN DEFENCE
Some important molecules secreted by JE-
• Cytokines
• Cell adhesion molecules
• Growth ...
85
LOCATION & FUNCTION OF CYTOKINES
Molecular Factor Location within the Junctional
Epithelium
Suggested Functions Referen...
86
LOCATION & FUNCTION OF C.A.M’S
Molecular Factor Location within the Junctional
Epithelium
Suggested Functions Reference...
Intercellular adhesion
molecule-1 (ICAM-1
or CD54)
Cell membrane of junctional
epithelial cells
Mediates cell-cell
interac...
88
LOCATION & FUNCTION OF GROWTH FACTORS
Molecular Factor Location within the
Junctional Epithelium
Suggested Functions Re...
89
LOCATION & FUNCTION OF PROTEASES
Molecular Factor Location within the
Junctional Epithelium
Suggested Functions Referen...
90
NATURAL ANTIMICROBIAL PEPTIDES AND PROTEINS
Molecular Factor Location within the Junctional
Epithelium
Suggested Functi...
91
CONNECTIVE TISSUE
CONNECTIVE TISSUE
• If the above mechanisms fail to prevent entry of pathogen, it reaches to the
connective tissue.
• Conn...
CONNECTIVE TISSUE CELLS
1. Fixed cells ( intrinsic cells)
• Fibroblasts
• Undifferentiated mesenchymal cells
• Adipocytes
...
MACROPHAGES (HISTIOCYTES)
• Derived from blood monocytes.
• Surface of the cell is thrown into numerous folds & finger lik...
Function-
• Defense
• Cleanup operation
• Immune reactions
MAST CELLS
• Ovoid connective tissue cell with spherical nucleus.
• Involved in inflammatory reactions, allergies & hypers...
LYMPHOCYTES
• They are the smallest of the free cells in the connective tissue.
• Lymphocytes circulate through both blood...
99
They appear as cells having thin rim of cytoplasm surrounding a deeply stained
heterochromatic nucleus.
• T-lymphocytes
• Have long life span & are involved in cell-mediated immunity.
• B-lymphocytes
• have variable life-span ...
102
REFRENCES
• Nanci A.Ten cate’s Oral histology
• CARRANZA’S CLINICAL PERIODONTOLOGY-10th and 11th edition
• Structure a...
Defence mechanism of gingiva
Defence mechanism of gingiva
Defence mechanism of gingiva
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Defence mechanism of gingiva

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The defense mechanism of gingiva includes GCF, Saliva, epithelial barrier and connective tissue cells. All these protect the periodontium from bacterial invasion.

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Defence mechanism of gingiva

  1. 1. DEFENCE MECHANISM OF GINGIVA Achi joshi MDS II
  2. 2. CONTENTS 1. INTRODUCTION 2. GINGIVAL CREVICULAR FLUID 1. Introduction 2. Formation 3. Functions 4. Method of collection 5. Amount and measurement 6. Composition 7. Clinical Significance 3. SALIVA 1. composition 2. Functions 3. Role of SALIVA in Defense of Gingiva. 4. EPITHELIAL BARRIER 1. Epithelial BARRIER 2. Functions and features of epithelia 3. Keratinocyte formation 4. Cell junctions 5. Langerhans CELLS 6. Junctional epithelium 5. CONNECTIVE TISSUE connective tissue cell 1. Macrophages 2. Plasma cells 3. Mast cells 4. Lymphocytes
  3. 3. INTRODUCTION DEFENSE MECHANISM OF GINGIVA EPITHELIAL SURFACE SALIVA GCF CONNECTIVE TISSUE
  4. 4. GINGIVAL CREVICE FLUID GCF is an altered serum transudate found in the gingival sulcus. Genco • Gingival crevice fluid (GCF) is a complex mixture of substances derived from serum, leukocytes, structural cells of the periodontium and oral bacteria. Uitto 2003
  5. 5. HISTORY • GCF , its composition and possible role in oral defense mechanisms were elucidated by the pioneering work of Waerhaug in 1950s • Brill and Krasse – (1959) indicated that the passage of fluid from the bloodstream through the tissues and exiting via the gingival sulcus.
  6. 6. • Löe et al. contributed to the use of GCF as an indicator of periodontal diseases (Periodontics 1965) • Egelberg continued to analyze GCF and focused his studies on the dentogingival blood vessels and their permeability as they relate to GCF flow. • Presence and functions of proteins, especially enzymes in GCF were first explored by Sueda, Bang and Cimasoni (1974)
  7. 7. FORMATION • The initial investigations of GCF by Brill and Krasse and Egelberg relate its formation to the inflammatory changes in the connective tissues underlying the sulcular and junctional epithelia.
  8. 8. • Brill and Krasse (1959) introduced filter paper into the gingival sulci of dogs previously injected intramuscularly with fluorescein; within 3 minutes the fluorescent material was recovered on the paper strips. • Flow of gingival fluid increased markedly following stimulation of the gingiva by tooth brushing , chewing, after intravenous injection of histamine or the development of inflammation . • This led to the conclusion that some irritation , whether chemical or mechanical, was necessary to induce the production of GCF and that it should therefore be considered as a pathological phenomenon.
  9. 9. PERMEABILITY OF THE JUNCTIONAL EPITHELIUM • Permeable to substances with a molecular weight upto 1000kD • Albumin • Endotoxin • Thymidine • Histamine • Phenytoin
  10. 10. • Alfano (1974) –hypothesis – flow of gingival fluid might be osmotically mediated • Pashley (1976) developed the concept, mathematically describing fluid flow across capillaries. The model assumes that when the production of fluid by the capillaries exceed its uptake by the lymphatics -oedema results - and gingival crevicular fluid leaves the area.
  11. 11. EXUDATE V/S TRANSUDATE Mathematical model of Pashley, illustrated within the gingival crevice. Cross-section of two capillaries and lymph vessel with arrows showing the passage of fluid. (a)Absence of inflammation: low vascular permeability and low permeability of the basement membrane results in low GCF flow and high % uptake by lymph vessels. (b) Macromolecules of plaque result in an osmotic gradient, increased vascular permeability and basement membrane changes, resulting in increased passage of fluid into the tissues and increased GCF production.
  12. 12. • GCF protein concentration suggested that inflamed gingivae had a protein concentration similar to that of serum. • Most proteins were significantly lower in GCF, but with a strong co-variation between the proteins studied in the two fluids, suggesting that GCF represents an inflammatory exudate of serum. CURTIS 1990
  13. 13. FUNCTION 1. It washes the crevice carrying out shed epithelial cells, leukocytes and bacterias and debris. 2. It contains plasma proteins which may influence epithelial attachment to tooth. 3. It contains 1. Antimicrobial agents- lysozymes. 2. PMNs macrophages 3. Immunoglobulins IgG
  14. 14. METHOD OF COLLECTION Gingival washing methods Capillary tubing or micropipettes Absorbent filter paper strips
  15. 15. GINGIVAL WASHING METHODS In this technique the gingival crevice is perfused with an isotonic solution of fixed volume. The fluid collected then represents a dilution of crevicular fluid and contains both cells and soluble constituents such as plasma proteins.
  16. 16. SEMIQUANTITATIVE SKAPSKI AND LEHNER (1976) • Useful for studying the number and functional state of cells and bacteria from the crevicular fluid. • Injection and reaspiration of a known amount of solution into the interdental gingival crevice, Does not permit absolute quantitative measurements Collection of crevicular fluid by means of gingival washings; 10ml of fluid (Hank’s balanced salt solution) is ejected from a microsyringe and re-aspirated.
  17. 17. • Proposed by Takamori(1963) and Oppenheim (1970) • Based on use individual acrylic appliances. • It involved the construction of a customized acrylic stent which isolated the gingival tissues from the rest of the mouth. The tissues were then irrigated for 15min, with a saline solution, using a peristaltic pump, and the diluted GCF was removed.
  18. 18. CAPILLARY TUBING OR MICROPIPETTES Capillary tubing of known diameter is placed at the entrance of the crevice and the fluid migrates up the tube by capillary action. This technique appears to be ideal as it provides an undiluted sample of ‘native’ GCF whose volume can be accurately assessed. DISADVANTAGES 1. collection time- from an individual site may exceed 30min. 2. difficulty of removing the complete sample from the tubing. Sueda T, Bang J, Cimasoni 1969
  19. 19. ABSORBING PAPER STRIPS • Used in 2 different ways • Intracrevicular • Brill (1962) • End of strips inserted into the sulcus or pocket until minimum resistance is felt. • Extracrevicular- Loe and Holm Pederson (1965)
  20. 20. EVALUATION OF THE FLUID COLLECTED • The amount of GCF collected is extremely small. • Measurements performed by Cimasoni showed that a strip of paper 1.5mm wide & inserted 1mm within the gingival sulcus of a slightly inflamed gingiva absorbs about 0.1mg of GCF in 3 min.
  21. 21. 1.Direct viewing or staining • Under a microscope fitted with a graticule for determining the wetted area 2. Stain the strip with alcoholic solution of ninhydrin • Stained area is measured with • Ordinary transparent ruler • Sliding caliper • Calibrated magnifying glass • Microscope with eyepiece graticule • Photometric techniques
  22. 22. 3. Weighing the strip • Weinstein et al (1967) inserted preweighed twisted thread into the gingival crevice ,weighed the sample. 4. Electronic device- periotron
  23. 23. PERIOTRON • An electronic measuring device which allows accurate determination of the GCF volume and subsequent laboratory investigation of the sample composition. • It measures the affect on the electrical current flow of the wetted paper strips. • It has two metal ‘jaws’ which act as the plates of an electrical condenser.
  24. 24. • If a dry strip is placed between the ‘jaws’, the capacitance is translated via the electrical circuitry and registers ‘zero’ on the digital readout. • A wet strip will increase the capacitance in proportion to the volume of fluid and this can be measured as an increased value in the readout. • The technique is rapid and has no detectable affect upon the GCF sample.
  25. 25. MEASURES SHOWING PERIOTRON INDICES IN RESPECT TO GINGIVAL DISEASES Periotron Reading Level of Gingival Inflammation Gingival Index 0-20 Healthy 0 21-40 Mild 1 41-80 Moderate 2 81-100 severe 3 Brochure from the original PeriotronA 600 Loe H, Holm Mann et al
  26. 26. COMPOSITION
  27. 27. CELLULAR ELEMENTS • Originate from blood , host tissue and subgingival plaque, Bacteria from adjacent plaque mass, desquamated epithelial cells • Transmigrating leukocytes • PMN’s • Monocytes/macrophages • lymphocytes
  28. 28. • Bacteria with in bacterial plaque • Microscopic observations • Some bacteria free float in GCF • Attached to host cells • Some engulfed by neutrophils. • Epithelial cells • Shed from junctional epithelium or sulcular epithelium Lange and Schroeder a. From sulcular epithelium • Extremely flattened • Greater amounts of cytoplasmic filaments b. From junctional epithelium • Contain lysosome like bodies-bottom of sulcus • Engulfed coccoid material- greater vacuolisation and karyolysis • Turnover • OSE 10 to 14 days • JE 4 to 6 days
  29. 29. • Leukocytes – in 1960 Sharry and Krasse determined that 47% of cells obtained from gingival sulcus are leukocytes • 95- 97% neutrophils • 1-2% lymphocytes • 2-3% monocytes • Numerous at the base and decrease coronally.
  30. 30. ELECTROLYTES • Sodium • 207-222 mEq/l • Potassium • Exceeds that of serum • 69mEq/l • Fluoride • Other ions • Calcium , magnesium and phosphate
  31. 31. ORGANIC COMPOUNDS1. Carbohydrates • Glucose, hexosamine and hexuronic acid • Glucose 3-6 times that of serum 2. Proteins • Around 6.9g/100ml (much less than serum) • γ,β,α1,α2 -globulins and albumin 3. Immunoglobulins – IgG, IgA, IgM 4. Other proteins • Albumin, fibrinogen, transferrin 5. Lipids • Phopholipids • Sources – serum, salivary, bacterial and tissue sources
  32. 32. METABOLIC AND BACTERIAL PRODUCTS • Lactic acid • Hydroxyproline – breakdown of collagen • Prostaglandins – PgE2 • Urea • Endotoxin • Cytotoxic substances- hydrogen sulphide • Antibacterial factors
  33. 33. ENZYMES • Acid phosphatase • Connective tissue catabolism • Attack teichoic acid –one of the components of bacterial cell wall • Sources – PMN’s, desquamating epithelial cells • Alkaline phosphatase • Sources – PMN’s • Pyrophosphatase • Βeta glucouronidase • Hydrolases found in azurophilic or primary granules • Responsible for final degradation of oligosaccharides • Source-Macrophages , fibroblasts, endothelial cells.
  34. 34. • Lysozyme • Hydrolyses β-1,4 – glycosidic bonds of peptidoglycans of bacterial cell wall • Increased in areas of increased destruction • Hyaluronidase • Proteolytic enzymes • Exopeptidases • Aminopeptidase • Endopeptidases • Cathepsin D • Elastase • Collagenases • Lactic dehydrogenase
  35. 35. GCF FLOW • It is the process of fluid moving into and out of the gingival crevice or pocket • Shallow pockets – 3 to 8µl/hr • Intermediate periodontal disease - 20µl/hr • Advanced periodontal disease- 137µl/hr • Is an important determinant in the ecology of the periodontal pocket. • Flushing action • Substances put in the pocket are rapidly flushed out. • Controlled release antibacterial therapy, compensates for the rapid removal of substances from the sulcus (UITTO, PERIO 2000: 2003)
  36. 36. Isolation effect • Substances from outside do not penetrate the sulcus easily • GCF is relatively isolated from saliva--Salivary amylase – low levels in GCF • Concentration of IgG is 100 times that of in saliva • Outward GCF flow inhibits retrograde salivary flow • Salivary contents do not generally enter the pocket
  37. 37. CLINICAL SIGNIFICANCE • Circadian periodicity • Greater in the evening and minimal in the morning –Bissada et al (1967) • Gingival fluid and sex hormones • Pregnancy, menstrual cycle, puberty • Increase in vascular permeability • Drugs in GCF • Drugs that are excreated through GCF- periodontal therapy. • Tetracycline and metronidazole.
  38. 38. • Gingival fluid as a sign of subclinical inflammation • Flow from crevice was demonstrated before clinical gingivitis was observed • Increase in vascular permeability of the venular type vessels in the connective tissue • Influence of mechanical stimuli • Increase in GCF • Periodontal therapy • Decrease in GCF – scaling and root planing • Increase in GCF – surgical procedures • Result of inflammatory reaction and loss of intact epithelial barrier
  39. 39. • GCF and diabetes • β glucouronidase – higher in diabeteics with poorer metabolic control • β glucouronidase is a predictor of periodontal disease activity • GCF and pregnancy • PGE2 is increased • PGE2 is a marker for current periodontal disease activity and decrease in birth weight
  40. 40. SALIVA • Saliva is clear, tasteless, odourless slightly acidic (ph6.8) viscid fluid, consisting of secretions from the parotid, sublingual and submandibular salivary glands and the mucous glands of the oral cavity.
  41. 41. SALIVA WATER (99.5%) SOLIDS (0.5%) ORGANIC (0.3%) INORGANIC (0.3%) GAMMA-GLOBULIN CATIONS ANIONS PTYLIN SODIUM CHLORINE MUCIN POTASSIUM BICARBONATE KALLIKREIN CALCIUM PHOSPHATE BRADIKYNIN MAGNESSIUM THIOCYNATE LYSOSOME FLUORIDE IMMUNOGLOBULIN IgG BLOOD GROUP ANTIGEN NERVE GROWTH FACTOR VIT C AND VIT K UREAAND URIC ACID CELLULAR COMPONENTS COMPOSITION
  42. 42. FUNCTIONS OF SALIVA 1. Fluid flow helps to remove bacteria and food debris. 2. Bio-carbonates and phosphate buffer the bacterial acid 3. Lubrication of oral mucosa 4. Antibacterial enzymes- lysozyme 5. Antibody – IgA 6. Maintains the tooth integrity. 7. Exchange of calcium and phosphate ions- remineralization of enamel 8. Contains coagulation factors. ELEY AND MANSON
  43. 43. ROLE OF SALIVA IN DEFENCE OF GINGIVA • Saliva exerts a major influence on plaque initiation, maturation and metabolism. • It also influences calculus formation, periodontal disease and caries. • Salivary secretions are protective in nature, because they maintain the tissue in normal Physiologic state. • Saliva exerts major influences: a) on plaque by mechanically cleansing the exposed oral surfaces. B) by buffering acids produced by bacteria. C) by controlling bacterial activity.
  44. 44. 1. Antibacterial factors Saliva contains lysozymes, myeloperoxidase, lactoperoxidase, glucoproteins, mucins & antibodies etc. (a) Lysozyme: Lysozyme is a hydrolytic enzyme that cleavage linkage beta-1, 4- glycosidic bond of peptidoglycans of bacterial cell wall. eg. Actinobacillus actinomycetemcomitans. (b) Lacto- peroxidase – thiocyanate: Bactericidal to some strains of lactobacillus & streptococcus by preventing accumulation of lysine & glutamic acids both of which are essentials for bacterial growth. Lactoferrin also effective against actinobacillus species.
  45. 45. (c) Myeloperoxidase: enzyme released by leucocytes and is bactericidal for actinobacillus. (d) Glycoproteins & mucin: It forms coating layer over tissue structures & provide lubrication & physical protection. The glycoprotein-bacteria interactions facilitate bacterial accumulation on the exposed tooth surface. (by making acquired pellicle to which bacteria attach) • Other salivary glycoproteins inhibit the sorption of some bacteria to the tooth surface and to epithelial cells of the oral mucosa.
  46. 46. 2. Salivary Antibodies: 1) Saliva IgA, IgG and IgM antibodies. 2) IgA Immunoglobulin found in Saliva. IgA • The predominant immunoglobulin in saliva is secretory IgA (sIgA) which is derived from plasma cells in the salivary glands. • Parotid gland are responsible for the majority of the IgA found in saliva (Bienenstock et al. 1980, Nair 1986). • sIgA -important in maintaining homeostasis in the oral cavity. It may control the oral microbiota by reducing the adherence of bacterial cells to the oral mucosa and teeth (Marcotte & Lavoie 1998).
  47. 47. IgG • Salivary IgG is primarily derived from serum via GCF and is present in low concentrations. • Consequently, the IgG concentration in saliva should increase as inflammation of the periodontal tissues becomes more severe and vascular permeability increases, resulting in increased flow of GCF (Wilton et al. 1989, Shapiro et al. 1979)
  48. 48. • Proteolytic enzymes in the saliva are generated by both the host and oral bacteria. These enzymes have been recognized as contributors to the initiation and progression of periodontal disease. • To combat these enzymes , saliva contains antiproteases that inhibit cysteine proteases such as cathepsins and anti-leucoproteases that inhibit elastase. • Another antiprotease identified as a tissue inhibitor of matrix metalloproteinase (TIMP) has been shown to inhibit the activity of collagen- degrading enzymes. ENZYMES
  49. 49. • The enzymes normally found in the saliva are derived from the salivary glands, bacteria, leukocytes, oral tissues,and ingested substances; the major enzyme is parotid amylase. • Certain salivary enzymes have been reported in increased concentrations in periodontal disease; these are- • hyaluronidase • lipase • ß-glucuronidase • chondroitin sulfatase • amino acid decarboxylases, • catalase,peroxidase, and • collagenase.
  50. 50. 2. Buffers & coagulation factor • Salivary buffer bicarbonate – carbonic acid system maintains the physiologic pH of oral cavity. • Saliva contains coagulation factor- factor viii, ix, x, PTA & hagman factor that hasten blood coagulation & protect wound from bacterial invasion. 3. Leukocytes: • Leukocytes reach the Oral Cavity migrating through the Gingival Sulcus. • Poly Morpho Nuclear Leukocytes chiefly found in Saliva mainly causes the Phagocytosis of Bacteria.
  51. 51. • Living PMNs in saliva are referred to as orogranulocytes, and their rate of migration into the oral cavity is termed the orogranulocytic migratory rate. • Some investigators think that the rate of migration is correlated with the severity of gingival inflammation and is therefore a reliable index for assessing gingivitis.
  52. 52. INTRODUCTION DEFENSE MECHANISM OF GINGIVA EPITHELIAL SURFACE SALIVA GCF CONNECTIVE TISSUE
  53. 53. EPITHELIUM
  54. 54. EPITHELIAL BARRIER • When active disease is present, the epithelial barrier function fails , results in bacterial invasion, inflammation and destruction of the connective tissue, with subsequent bone loss and possible tooth loss. 54
  55. 55. Now, it is well established that while the epithelial compartment does provide a physical barrier to infection, it also has an active role in innate host defence.
  56. 56. FEATURES OF EPITHELIUM Architectural integrity 1. Cell–cell attachments • Desmosome , Adherent junctions, Tight junctions, Gap junctions • Keratin cytoskeleton 2. Cell to tooth attachment • Basal lamina - hemidesmosome junction Cell types important in defence Keratinocyte Langerhans cells Melanocyte 56
  57. 57. GINGIVAL EPITHELIAL Cell types Keratinocytes Langerhans cell immunity ) Melanocyte to make & transfer pigment Merkel cell (sensory) dead alive Nerve cell represented by its axon
  58. 58. EPITHELIUM :BARRIER FUNCTION 1. KERATINOCYTE FORMATION 3. CELL JUNCTIONS 2. LANGERHANS CELLS 58
  59. 59. 1. Cell–cell attachments and the overall integrity of the tissue as well as the process of differentiation (keratinization) of the tissue leading to the toughened, mechanically resistant surface. 2. Desmosomes mediate keratinocyte cell–cell attachment, and hemidesmosomes mediate keratinocyte–basal lamina attachment. 3. Langerhans cells within the epithelium do not have desmosomal attachments. 4. Constant cell renewal is critical to tissue turnover and continual differentiation. Cell migration is critical to wound healing and re- epithelialization. 5. Antimicrobial peptides contribute to the barrier to microbial invasion 59FUNCTION
  60. 60. Keratinocyte formation • Following cell division in the basal layer and the resultant birth of a new keratinocyte, about 30 days are required for the new cell to traverse the epithelium to reach the stratum corneum. • This time interval interval is known as the epithelial cell turnover time .
  61. 61. They are found in oral epithelium & in smaller amounts in sulcular epithelium & are absent from JE They are characterized by Birbeck granules FUNCTION • Role in the immune reaction as antigen-presenting cells for lymphocytes. • Langerhans cells penetrate the epithelium in response to antigenic challenge by bacterial plaque and Act as shuttle between epithelium and regional lymph nodes. Langerhans Cells
  62. 62. UNDER ELECTRON MICROSCOPE Basement membrane Lamina Lucida (400 Å – wide) is in immediate contact with the epithelial cells of the stratum basale, to which it is connected via hemidesmosomes, containing proteoglycan laminin. Lamina densa contacts the connective tissue compartment and is attached firmly to it via anchoring fibrils (1 m in length) EPITHELIAL–CONNECTIVE TISSUE JUNCTION
  63. 63. DESMOSOMES • Play a decisive role in the firm attachment of the cells to the internal basal lamina on the tooth surface. • Act as specific sites of signal transduction and, thus, participate in regulation of gene expression, cell proliferation and cell differentiation.
  64. 64. • Desmosomes have a typical structure consisting of two dense attachment plaques into which tonofibrils insert and an intermediate, electron- dense line in the extracellular compartment. • Tonofilaments, are the morphologic expression of the cytoskeleton of keratin proteins, radiate in brush-like fashion from the attachment plaques into the cytoplasm of the cells. • The space between the cells shows cytoplasmic projections resembling microvilli that extend into the intercellular space and often interdigitate.
  65. 65. ZONA OCCLUDENS (TIGHT JUNCTIONS) • Membranes of the adjoining cells fuse and allow ions & small molecules to pass from one cell to other. • It is probably a typical structure in the uppermost layer of oral gingival epithelium, is and functions as barrier (Hatakeyama et al.2006JPR)
  66. 66. • FUNCTIONS: HOLDS CELLS TOGETHER BLOCK MOVEMENT OF INTERGRAL MEMBRANE PROTEIN
  67. 67. ZONA ADHERENS (GAP JUNCTIONS ) - • Intercellular space narrows to 2 – 3 nm. • Transmembrane proteins (connexin) in adjacent cells fuse to form a channel for movement of molecules from one cell to another. • THESE ARE ABLE TO OPEN AND CLOSE
  68. 68. JUNCTIONAL EPITHELIUM • The junctional epithelium consists of a collar like band of stratified squamous non-keratinizing epithelium. • It is three to four layers thick in early life, but the number of layers increases with age to 10 or even 20 layers. • It tapers from its coronal end, which may be 10 to 29 cells wide to one or two cells at its apical termination, located at the cementoenamel junction in healthy tissue
  69. 69. Junctional Epithelium internal basal lamina to tooth surface (epithelial attachment) external basal lamina. to gingival connective tissue –
  70. 70. JE • The basal cells and the adjacent 1 to 2 suprabasal cell layers are cuboidal to slightly spindle-shaped. • All remaining cells of the suprabasal layer are flat, oriented parallel to the tooth surface, and closely resemble each other • The innermost suprabasal cells (facing the tooth surface) DAT cells (Salonen et al., 1989). • They form and maintain the ‘internal basal lamina’ that faces the tooth surface.
  71. 71. JE • Basal lamina of the junctional epithelium resembles that of endothelial and epithelial cells in its laminin content • It differs in its internal basal lamina, having no type IV collagen. • Cells of the junctional epithelium are involved in the production of laminin and play a key role in the adhesion mechanism. • Lysosomal bodies are found in large numbers which help in bacterial eradication. • JE have wide intercellular spaces compared to sulcular and oral epithelium
  72. 72. 76 WIDE INTERCELLULAR SPACE MAY BE A DOUBLE ENDED SWORD widened spaces ALLOW the transmigration of GC fluid and leukocytes , and thus prevent the entry of bacteria (Hatakeyama et .al,2006) at the same time it provides passage for bacterial products ,into the connective tissue
  73. 73. 77 JE : ROLE IN DEFENCE • In contrast to most other epithelia, there is no keratinizing epithelial cell layer at the free surface of the junctional epithelium that could function as a physical barrier. • Other structural and functional characteristics of the junctional epithelium must compensate for the absence of this barrier.
  74. 74. 78 ATTACHMENT APPARATUS • consists of hemidesmosomes at the plasma membrane of the cells directly attached to the tooth (DAT cells) and a basal lamina-like extracellular matrix, termed the internal basal lamina, on the tooth surface
  75. 75. 79 • DAT cell shows the structural and molecular composition of the epithelial attachment apparatus (EAA). • The hemidesmosomes at the plasma membrane are associated with the α6β4 integrin that communicate with Ln-5 = laminin 5 located mainly in the internalbasal lamina, • the extracellular domain (?) for BP180 is a collagenous protein (perhaps type VIII), that has not yet been definitely characterized. • N = nucleus of a DAT cell, • IF = cytoplasmic keratin filaments • LL = lamina lucida, • LD =lamina densa, • SLL = sublamina lucida, • IBL =internal basal lamina. • BP =bullous pemphigoid (PERIO 2000: 2003) The interaction between the different components of the extracellular matrix and the cell surface molecules linked to the intracellular cytoskeleton is fundamental for cell adhesion, cell motility, synthetic capacity, tissue stability, regeneration and responses to external signals Uitto, 1991
  76. 76. TURNOVER OF JUNCTIONAL EPITHELIAL CELLS • Previously it was thought that only epithelial cells facing the external basal lamina were rapidly dividing. • Evidence indicates that a significant number of the DAT cells are, like the basal cells along the connective tissue, capable of synthesizing DNA, which demonstrates their mitotic activity. (Tonetti ) • DAT cells have a more important role in tissue dynamics and reparative capacity of the junctional epithelium.
  77. 77. The mechanism of DAT cell turnover is not fully understood. Considering the fact that the DAT cells are able to divide and migrate, three possible mechanisms can be proposed. These are- 1. Dividing DAT cells replace degenerating cells on the tooth surface 2. Daughter cells enter the exfoliation pathway and migrate coronally between the basal cells and the DAT cells to eventually break off into the sulcus 3. Epithelial cells move/migrate in the coronal direction along the tooth surface and are replaced by basal cells migrating round the apical termination of the junctional epithelium
  78. 78. 83JE:ROLE IN ANTIMICROBIAL DEFENCE In the coronal part of the JE quick cell exfoliation 1. (A) because of rapid cell division (B) and funnelling of JE cells towards the sulcus hinder bacterial colonization 2. .Laterally, the (external) basement membrane forms an effective barrier against invading microbes 3. Active antimicrobial substances are produced in JE cells. These include defensins and lysosomal enzymes 4. Epithelial cells activated by microbial substances secrete chemokines, e.g. interleukin-8 and cytokines, e.g. interleukins -1 and -6, and tumour necrosis factor-a that attract and activate professional defence cells, such as lymphocytes (LC) and polymorphonuclear leukocytes (PMN). Their secreted product, in turn, cause further activation of the junctional epithelial cells
  79. 79. 84 IMPORTANT MOLECULES IN DEFENCE Some important molecules secreted by JE- • Cytokines • Cell adhesion molecules • Growth factors
  80. 80. 85 LOCATION & FUNCTION OF CYTOKINES Molecular Factor Location within the Junctional Epithelium Suggested Functions Reference Interleukin-8 (Il-8) In junctional epithelial cells near the sulcus bottom Chemotaxis; guiding PMNs toward the sulcus bottom Tonetti et al., 1994, 1998 Interleukin-1(Il-1) Interleukin-6(Il-6) Tumor necrosis factor-(TNF-a) In junctional epithelial cells and macrophages in the coronal portion of the junctional epithelium Pro-inflammatory cytokines that contribute to the innate immune defence Miyauchi et al., 2001
  81. 81. 86 LOCATION & FUNCTION OF C.A.M’S Molecular Factor Location within the Junctional Epithelium Suggested Functions Reference Integrins Cell membrane of junctional epithelial cells Mediate cell-matrix and cell- cell interactions Hormia et al., 1992, 2001 Del Castillo et al., 1996 Thorup et al., 1997 Gurses et al., 1999 (CEA-CAM1) Carcino-embryonic antigen related cell adhesion molecule -1 Cell membranes of leukocytes and junctional epithelial cells Adhesion between epithelial cells; contributes to the guidance of PMNs through the junctional epithelium; participates in the regulation of cell proliferation, stimulation, and co-regulation of activated T- cells; cell receptor for certain bacteria Odin et al., 1988 Öbrink, 1997 Hauck et al., 1998 Kammerer et al., 1998 Singer et al., 2000 Heymann et al., 2001
  82. 82. Intercellular adhesion molecule-1 (ICAM-1 or CD54) Cell membrane of junctional epithelial cells Mediates cell-cell interactions in inflammatory reactions; guiding PMNs toward the sulcus bottom Crawford, 1992 Gao and Mackenzie, 1992 Tonetti, 1997 Tonetti et al., 1998 Lymphocyte function antigen-3 (LFA-3) Cell membrane of junctional epithelial cells Mediates cell-cell interactions in inflammatory reactions; controls leukocyte migration to inflammatory sites Crawford, 1992 Epithelial cadherin (E-cadherin) Epithelial intercellular junctions Critical in intercellular adhesion and thus crucial for maintaining structural integrity Ye et al., 2000 Molecular Factor Location within the Junctional Epithelium Suggested Functions Reference
  83. 83. 88 LOCATION & FUNCTION OF GROWTH FACTORS Molecular Factor Location within the Junctional Epithelium Suggested Functions Reference Epidermal growth factor receptor (EGFR) Cell membrane of junctional epithelial cells Signal transduction Nordlund et al., 1991 Epidermal growth factor (EGF) In junctional epithelial cells Mitogen that participates in epithelial growth, differentiation, and wound healing Tajima et al., 1992
  84. 84. 89 LOCATION & FUNCTION OF PROTEASES Molecular Factor Location within the Junctional Epithelium Suggested Functions Reference Tissue plasminogen activator (t-PA) In junctional epithelial cells Serine protease that converts plasminogen into plasmin, which in turn degrades extracellular matrix proteins and activates matrix metalloproteinases Schmid et al., 1991 MMP-7 or matrilysin) In suprabasal junctional epithelial cells Proteolytic degradation of the extracellular matrix Uitto et al., 2002
  85. 85. 90 NATURAL ANTIMICROBIAL PEPTIDES AND PROTEINS Molecular Factor Location within the Junctional Epithelium Suggested Functions Reference Defensins In PMNs and gingival crevicular fluid PMN-produced antimicrobial substances that contribute In PMNs and gingival crevicular fluid to the innate immune defense Dale, 2002 Human-defensin-1 (hBD1) Human-defensin-2 (hBD2) Weak expression in junctional epithelial cells Epithelially produced antimicrobial substances that contribute to innate host defense Dale, 2002 Cathelicidin LL-37 In junctional epithelial and inflammatory cells Antimicrobial and chemotactic substance produced by both PMNs and epithelial cells; contributes to the regulation of the innate immune defense Dale, 2002
  86. 86. 91 CONNECTIVE TISSUE
  87. 87. CONNECTIVE TISSUE • If the above mechanisms fail to prevent entry of pathogen, it reaches to the connective tissue. • Connective tissue offers a potential paradise. The abundant extracellular material provides all the necessary nutrients as well as an ideal warm, humid, oxygenated environment. • Without vigorous immunological defences within the connective tissue, any small break in the epithelium would convert the body into an excellent bacterial culture.
  88. 88. CONNECTIVE TISSUE CELLS 1. Fixed cells ( intrinsic cells) • Fibroblasts • Undifferentiated mesenchymal cells • Adipocytes • Macrophages(histiocytes) 2. Free cells( extrinsic/wandering cells) • Free macrophages • Plasma cells • Mast cells • leucocytes
  89. 89. MACROPHAGES (HISTIOCYTES) • Derived from blood monocytes. • Surface of the cell is thrown into numerous folds & finger like projection. • These folds are active in phagocytosis.in that they engulf the substances to be phagocytosed. • When macrophages encounter large foreign bodies they fuse to form large cells with up to 100 nuclei. These multinucleate cells are called foreign body giant cells. • During antigenic stimulation or inflammation the fixed macrophages withdraw their processes & become free macrophages.
  90. 90. Function- • Defense • Cleanup operation • Immune reactions
  91. 91. MAST CELLS • Ovoid connective tissue cell with spherical nucleus. • Involved in inflammatory reactions, allergies & hypersensitivity reaction. • Do not produce antibodies but are dependent upon plasma cells to produce antibodies that bind to their surface. • Substances released by mast cells 1. Histamin 2. Eosinophil chemotactic factor of anaphylaxis 3. Heparin 4. Slow reacting substance of anaphylaxis
  92. 92. LYMPHOCYTES • They are the smallest of the free cells in the connective tissue. • Lymphocytes circulate through both blood and connective tissue. They possess in their secretory product and on their cell membranes the ability to recognize and bind to foreign substances. • Number increases dramatically at the sites of tissue inflammation & repair.
  93. 93. 99 They appear as cells having thin rim of cytoplasm surrounding a deeply stained heterochromatic nucleus.
  94. 94. • T-lymphocytes • Have long life span & are involved in cell-mediated immunity. • B-lymphocytes • have variable life-span & are involved in the production of antibodies.
  95. 95. 102 REFRENCES • Nanci A.Ten cate’s Oral histology • CARRANZA’S CLINICAL PERIODONTOLOGY-10th and 11th edition • Structure and function of interface in health and disease:Periodontology 2000, Vol. 31, 2003, 12–31 • The Junctional Epithelium: from Health to Disease J DENT RES 2005 84: 9 AND J DENT RES 2003 82: 158 • Expression pattern of adhesion molecules in junctional epithelium differs from that in other gingival epithelia J Periodont Res 2006; 41; 322–328

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