GINGIVAL CONNECTIVE TISSUE ....DR SANDIP BHATTACHARYYA...PGT..DR RADC&H, KOLKATA.

1. GINGIVAL CONNECTIVE TISSUE
The gingival connective tissue is largely a fibrous connective tissue
that has elements originating directly from the oral mucosa
connective tissues as well as some fibers (dentogingival) that
originate from the developing dental follicle.
The connective tissue of the gingiva is known as the lamina
propria, and it consists of two layers…
Papillary layer and Reticular layer

2. Connective tissue contains-
 Collagen fibers (about 60% by Volume)
Schluger et al. 1977
Fibroblasts (5%)
Matrix (about 35%)
Vessels and nerves

3. The different types of cell present in the
connective tissue are:
Fibroblasts
Mast cells
Macrophages
Inflammatory cells

4. Fibroblast
Gingival connective tissue fibroblasts originate
from perifollicular mesenchyme, a derivative of
the stomodeal mesoderm.
The fibroblast is a spindle‐shaped or stellate
cell with an oval‐shaped nucleus containing
one or more nucleoli.

5. • The cytoplasm contains a well‐developed granular
endoplasmic reticulum with ribosomes. The Golgi
complex is usually of considerable size and the
mitochondria are large and numerous.

6. • Fibroblasts are the predominant cells of connective
tissue
• They are responsible for the formation and
maintenance of the fibrous components and the
ground substance of connective tissue.
• The resting fibroblast is an elongated cell with little
cytoplasm and a dark-staining, flattened nucleus
containing condensed chromatin
• Active fibroblasts have an oval shaped,pale-staining
nucleus and a greater amount of cytoplasm

8. • The degree of synthetic and secretory capacity of
fibroblasts is evidenced by the amount of rough
endoplasmic reticulum, secretory granules, and
mitochondria, and the extent of the Golgi complex
in their cytoplasm.
• Fibroblasts exhibit motility and contractility,
which are important during connective tissue
formation and remodeling and during wound
repair

9. Mast cell
• Mast cells are important in the primary response to
injury because they are located in tissues.
• The cytoplasm is characterized by the presence of
a large number of vesicles of varying size. These
vesicles contain biologically active substances
such as proteolytic enzymes, histamine, and
heparin.
 Mast cells express on their surface the receptor
(FcεRI) that binds the Fc portion of IgE antibody.

10.  TNF release from mast cells has been found to be
crucial for neutrophil recruitment and pathogen
clearance.
 On activation from stimuli including allergen binding,
infection, and trauma, mast cells produce histamine,
cytokines, eicosanoids, proteases,and chemokines,
which leads to vasodilatation, capillary leakage, and
immunocyte recruitment.
 Mast cells are thought to be important cosignaling
effector cells of the immune system via the release of
IL-3, IL-4, IL-5, IL-6, IL-10, IL-13, and IL-14, as well as
macrophage migration–inhibiting factor.
----Bachelet I, Levi-Schaffer F, 2007

11. Macrophage
Macrophages are tissue cells derived from
hematopoietic stem cells in the bone marrow and
from progenitors in the embryonic yolk sac and
fetal liver during early development.
Circulating cells of this lineage are known as
monocytes.

12. • There are two major pathways of macrophage activation,
called classical and alternative pathway
• Classical one, designed to destroy the offending agents, and
this is followed by alternative activation, which initiates tissue
repair by angiogenesis, activate fibroblasts, and stimulate
collagen synthesis.

13. Function of Macrophages are:-
 Ingest and eliminate microbes and dead tissues.
 Initiate the process of tissue repair and are involved in scar
formation and fibrosis.
 Macrophages display antigens to T lymphocytes and respond
to signals from T cells, thus setting up a feedback loop that is
essential for defense against many microbes by cell-mediated
immune responses.

14. Inflammatory cells
The neutrophilic granulocytes, also called
polymorphonuclear leukocytes.
A. The nucleus is lobulated and numerous
B. lysosomes containing lysosomal enzymes,
are found in the cytoplasm.
The lymphocytes
Plasma cells

15. Collagen fibers
Predominate in the gingival connective tissue and
constitute the most essential components of the
periodontium
The synthesis and the composition of collagen
fibers produced by fibroblasts
The smallest unit, the collagen molecule, is often
referred to as tropocollagen is approximately
3000 Å long and has a diameter of 15 Å.

16. • Collagen are composed of three polypeptide alpha
chains coiled around each other to form the typical
collagen triple-helix configuration
• Each chain contains about 1000 amino acids
• The amino acid glycine in every third position
(Gly-X-Y repeating sequence), of hydroxyproline
and hydroxylysine

17. Collagen synthesis
Tropocollagen synthesis takes place inside the
fibroblast from which the tropocollagen
molecule is secreted into the extracellular
space.
Thus, the polymerization of tropocollagen
molecules to collagen fibers takes place in the
extracellular compartment
Tropocollagen molecules are aggregated
longitudinally to form protofibrils which are
subsequently laterally aggregated parallel to
collagen fibrils (CFR).

19. • In the tissue, the fibers are usually arranged in
bundles. As the collagen fibers mature,
covalent cross‐links are formed between the
tropocollagen molecules, resulting in an
age‐related reduction in collagen solubility
• Cementoblasts and osteoblasts are cells which
also possess the ability to produce collagen

21. • Collagen type I forms the bulk of the lamina
propria and provides the tensile strength to the
gingival tissue. (Narayanan and Page, 1983a)
• Type III collagen is also a principal component
of the gingival connective tissues and together
with type I collagen is uniformly distributed
throughout the connective tissue (Rao et al,
1979; Wang et al, 1980; Chavrier et al, 1984;
Narayanan et al, 1985; Romanos et al, 1991)

22. • Type I:III ratio of 7:1 (Nathan et al 1979)
• Type IV collagen (argyrophilic reticulum fiber)
branches between the collagen type I bundles,
and it is continuous with fibers of the basement
membrane and the blood vessel walls.{main
collagenous component of basement
membrane (Chavrier et al 1981).

23. • Healthy human gingival connective tissue appears to
be arranged in two patterns of organization at the
ultrastructural level: Pattern I (PI) and Pattern II (PII)
• PI is dense pattern of organization mainly constituted
of large, dense bundles of thick collagen fibers
• PII is a loose pattern of organization, mainly
constituted of short, thin collagen fibers mixed with a
fine reticular network, especially located under or
around basement membrane.

24. • Ultrastructural immunoperoxidase labelling of types
I, III, and IV collagen demonstrates that gingival
connective tissue is made of an intricate pattern of
type I and III collagen where type I collagen fibers
are preferentially organized in large dense bundles in
PI, whereas a fibrous and fibrillar type III collagen
network is predominant in PII.
• Type IV collagen appears to be the main collagenous
component of the basement membranes.
--C.chavrier et al 1984

25. • Pattern I is mainly composed of dense type I
collagen bundles.
• Pattern II is composed of both types I and III
collagen but shows a predominance of type III
collagen.
• Gingival fibroblasts of pattern I tissue should
be able to synthesize both types I and III
collagen with a high type I/III ratio whereas
gingival fibroblasts of pattern II could produce
both type I and type III collagen with a lower
type l/III collagen ratio.
--(C. chavrier et al 1984)

26. • Ultrastructural fibrous feature of type I
collagen is in agreement with the notion of
stability (Peyrol & Grimaud, 1981) while the
fibrillar nature of type III collagen is in
agreement with the notion of remodelling
ability. (C. chavrier et al 1984)

27. Reticulin fibers
• Seen in the photomicrograph,exhibit
argyrophilic staining properties and are
numerous in the tissue adjacent to the
basement membrane. Composed of type III
collagen, secreted by reticular cells.
• Reticulin fibers are present at the epithelium–
connective tissue and the endothelium–
connective tissue interfaces

28. Oxytalan fibers
• Fullmer & Lillie (1958) named the fibers oxytalan
in recognition of their resistance to solubility in
acid, which contrasts with collagen.
• Scarce in the gingiva but numerous in the
periodontal ligament
• Composed of long thin fibrils with a diameter of
approximately 150 Å(Carmichael &Fullmer 1966,
Sheetz et al. 1973).

29. These connective tissue fibers can be
demonstrated under light microscopy only
after previous oxidation with peracetic acid

30. Elastin fibers
• Elastin is a minor constituent of gingival
connective tissue, accounting for
approximately 6% of the total tissue protein
(Chavrier, 1990).
• Cell surface receptors for elastin have been
identified and may be associated with cell
chemotaxis (Senior et al, 1980).
• Elastin is present in relatively small amounts
in the fixed, inflexible attached gingiva but it
is more prominent in the submucosal tissues of
the more movable and flexible alveolar
mucosa (Bartold. 1991).

31. Ground substance
• It is composed of proteoglycans (mainly hyaluronic
acid and chondroitin sulfate) and glycoproteins
(mainly fibronectin)
• By definition, a proteoglycan is composed of a
single protein core to which one or more
glycosaniinoglycan side chains are covalently
bound (Hardingham and Fosang,1992)
• The proteins bound covalently to
glycosaminoglycans are called “core proteins.”

32. • The amount of carbohydrate in a proteoglycan is
usually much greater than that found in a
glycoprotein and may comprise up to 95% of its
weight.
• There are at least seven GAGs: hyaluronic acid
(hyaluronan), chondroitin sulfate, keratan sulfates I
and II, heparin, heparan sulfate, and dermatan
sulfate.
• GAGs are unbranched polysaccharides made up of
repeating disaccharides, one component of which is
always an amino sugar(hexosamine )
• The other component of the repeating disaccharide
(except in the case of keratan sulfate) is a uronic acid,

33. Proteoglycans

34. GLYCOPROTEINS
• The glycoproteins are proteins that contain
oligosaccharide chains (glycans) covalently
bound to amino acids
• Fibronectin binds fibroblasts to the fibers and
many other components of the intercellular
matrix, thereby helping to mediate cell
adhesion and migration.
• Laminin (glycoprotein found in the basal
lamina of about 850 kDa and 70 nm length)
serves to attach it to epithelial cells

35. • Fibronectin binds to cells via a
transmembrane receptor protein which
belongs to the integrin class of proteins .
• Integrins are heterodimers, containing various
types of α and β polypeptide chains.

36. Gingival Fibers
• These fibers consist of Type I collagen
• The gingival fibers have the following
functions
. To brace the marginal gingiva firmly against
the tooth
. To provide the rigidity necessary to withstand
the forces of mastication without being
deflected away from the tooth surface
To unite the free marginal gingiva with the
cementum of the root and the adjacent
attached gingiva

37. Circular fibers fiber bundles which run
their course in the free gingiva and encircle the tooth in
a cuff‐ or ring‐like fashion.
Dentogingival fibers embedded in the
cementum of the supra‐alveolar portion of the root and
project out from the cementum in a fan‐like
configuration into the free gingival tissue of the facial,
lingual, and interproximal surfaces.
Dentoperiosteal fibers embedded in the same
portion of the cementum as the dentogingival fibers,
but run their course apically over the vestibular and
lingual bone crest and terminate in the tissue of the
attached gingiva.

38. Trans‐septal fibers Extend between the
supra‐alveolar cementum of approximating teeth. It
run straight across the interdental septum and are
embedded in the cementum of adjacent teeth.

39. Repair of gingival connective tissue
• Because of the high turnover rate, the
connective tissue of the gingiva has
remarkably good healing and regenerative
capacity.
• It generally shows little evidence of scarring
after surgical procedure.

40. Function of gingival connective tissue
• The gingival connective tissue serves primarily to
protect the root surface and alveolar bone from
the external oral environment
• Support and fixation of teeth within their alveolar
housing and provides adequate support for the
epithelial tissue
• The gingival connective tissue provide the stage
upon which the host response acts out its role of
surveillance, interception and removal of foreign
material.

41. Blood Supply
• The gingiva receives its blood supply mainly
through supraperiosteal blood vessels which
are terminal branches of the sublingual artery
(a.s.), the mental artery (a.m.), the buccal
artery (a.b.), the facial artery (a.f.), the greater
palatine artery (a.p.), the infra orbital artery
(a.i.), and the posterior superior dental artery
(a.ap.).

42. Gingiva receives
its blood supply from (1) supraperiosteal blood vessels,
(2) the blood vessels of the periodontal ligament,
and (3) the blood vessels of the alveolar bone.

43. Lymphatic system
• It progresses into the collecting network
external to the periosteum of the alveolar
process and then moves to the regional lymph
nodes, particularly the submaxillary group
• lymphatics just beneath the junctional
epithelium extend into the periodontal
ligament and accompany the blood vessels
• The labial and lingual gingiva of the
mandibular incisor region is drained to the
submental lymph nodes

44. • The palatal gingiva of the maxilla is drained to
the deep cervical lymph nodes

45. Nerves
• Within the gingival connective tissues, most
nerve fibers are myelinated and closely
associated with the blood vessels
• Gingival innervation is derived from fibers that
arise from nerves in the periodontal ligament
and from the labial, buccal,and palatal nerves.

46. INNERVATION

47. RECEPTORS:
Meshwork Of Terminal
Argyrophilic Fibres
Meissner’s Corpuscles – Tactile
Sensaion
Krause-type End Bulbs –
Temperaure (Coiled Terminals)
Encapsulated Spindle Receptors
Free Nerve Endings