Detailed description of periodontal ligament in health.

1. Dr Heenal Adhyaru
Department of Periodontology
1

2. PDL
Cellular
element
Extra cellular
substance
Fibers
Ground
substance
2
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

3. 3
Fibers
Ground
substances
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

4.  Principal fiber: Collagen fibers
 Secondary fibers
 Reticular fibers
 Elastic fibers
4Periodontology 2000, Vol. 3, 1993, 9-38

5.  Collagen molecule
 Protein
 Structural component of PDL
 Multifunctional protein
 Provide the tensile strength
 Influence the cellular activities
5
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

6.  Structural features:
1. Presence of triple helical structure-α
chains
2. Glycine occupies every third position
(Gly-X-Y)
3. Two unique amino acid:
1. Hydroxyproline (Hyp)
2. Hydroxylysine (Hyl)
4. Lysine derived intra and inter molecular
cross links for stabilization of collagen
molecule
6
P Mark Bartold’s Biology of the Periodontal Connective
tissue

7. 7
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

8.  The collagen superfamily is subdivided into nine
subfamilies largely based on their
supramolecular assemblies:
1. Fibrillar collagen
2. Basal lamina collagen
3. Fibril-associated collagens with interrupted
triple helices (FACIT)
4. Network forming collagens
5. Anchoring fibril collagen
6. Microfibril forming collagen
7. Transmembrane collagen
8. Multiplexin (endostatin-forming) collagens
9. Other collagen
8
Ten Cate’s Oral Histology 8th edition.

9. 9
I
VI
III
XII
V
IV
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

10.  Fibrillar collagen:
 Collagen type I, III and V
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Ten Cate’s Oral Histology 8th edition.

11. 11
Collagen type I
Collagen type III
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

12. 12

13.  Basal lamina collagen
 Collagen type IV
 It is similar to type I but assemble in
sheetlike or chicken wire configuration.
 Although this collagen is specifically
associated with basement membrane, it may
have a structural role in maintaining the
integrity of the PDL by anchoring the
elastic system to the vasculature.
13
Ten Cate’s Oral Histology 8th edition.

14.  Microfibril forming collagen
 Collagen type VI
 It has binding properties for cells,
proteoglycans and type I collagen and serve
as a bridge between the cells and the
matrix.
 The molecule may be central in retaining
the integrity and elasticity of the ECM
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Ten Cate’s Oral Histology 8th edition.

15.  Fibril-associated collagens with interrupted
triple helices (FACIT)
 Collagen type XII
 They consists of chains that have different
length and contains a variety of
noncollagenous domains and exhibit several
interruptions in the triple helix.
 They link the ‘fibrillar’ collagen fibers and
organize the ECM (Olsen, 1989)
15
Ten Cate’s Oral Histology 8th edition.

16.  Form bundles (Melcher and Eastoe, 1969)
 Indifferent fiber plexus (Shackleford
1971, 1973; Svejda and Skach 1973)
 Wavy course (Sloan, 1987a, b)
 Cytoplasmic processes of fibroblasts
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

17.  Width of fibrous band: 100-150 ɥm
 Diameter of fiber bundles
 Cementum: 3-10 ɥm
 Alveolar bone: 10-20 ɥm
 In PDL: 1-4 ɥm
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

18. 1. Alveolar crest
fibers
2. Horizontal
fibers
3. Oblique fibers
4. Inter-
radicular
fibers
5. Apical fibers
18
Ten Cate’s Oral Histology 8th edition.

19. Fibers Supposed function
Alveolar
crest
Retain tooth in socket;
Oppose lateral forces;
Protect deeper
periodontal ligament
structures
Horizont
al
Restrain lateral tooth
movement
Oblique Resist axially directed
forces
Inter-
radicular
Aid in resisting tipping
and torquing;
Resist luxation
Apical Prevent tooth tipping;
resist luxation;
Protect blood, lymph and
nerve supplies to tooth
19Periodontology 2000, Vol. 3, 1993, 9-38

20. 20
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

21. 21
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

22.  The terminal portion of the principal fibers
that are inserted into cementum and bone
are termed as Sharpey’s fibers.
 Orientation:
 Mineralization:
 Transalveolar fibers:
22
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

23. 23
Sharpey’s fibers
peripherial staining
for type III
collagen
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

24.  They are located between and among the
principal fiber groups.
 These are relatively nondirectional and
randomly oriented collagen bundles.
 They often appear to transverse the PDL
space coronoapically and they are often
associated with paths of vascular and nerve
elements.
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

25.  Reticular fibers:
 They are fine, immature type III
collagen with argyrophilic staining
properties.
 They often appear to form a lattice-like
arrangement.
 They are related to basement membrane
of blood vessels and epithelial cells of
PDL.
25
Ten Cate’s Oral Histology 8th edition.

26.  Elastic fibers:
 Three types of elastic fibers
 Mature : elastin fibers
 Immature: elaunin fibers and oxytalan fibers
 (Cotta- Pereira et al 1977)
 Precursor of elastic fibers (Franzblau and Faris 1981;
Chavrier et al., 1988)
 Oxidation before elastin stain.
 Formation: 2 distinct components
 Core of elastin protein
 Surrounding microfibrils (10-15 nm)
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

27.  In PDL:
 Oxytalan fibers and elauin fibers (Johnson
and Pylypas 1992)
 Run vertically from cementum apically,
forming branching mesh work that surround
tooth and terminates in arteries, veins and
lymphatic vessels.
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

28.  Functions:
 Dampens lateral Masticatory forces (long
range reversible extensibility property)
 Like elastic fibers they straightened on
extrusion and wavy with forced intrusion
(Sims, 1976)
 Attachment of oxytalan fibers would be
necessary:
 Direct: collagen interweave at right angle
 Indirect: vasculature
 Close relationship to blood vessels and
nerve endings: act as part of a
mechanoreceptor system
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

29. 29
Oxytalan fibers
surrounded by
collagen fibers
A: oxytalan fibers
B: collagen fibers
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

30.  The ground substance of PDL can be
described as a gel-like matrix in which are
embedded the cellular and fibrous
components.
 Fibroblast family synthesize two main
classes of macromolecules
(glycoconjugates)
 Proteoglycans
 Glycoproteins and other non collagenous
proteins
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

31.  Proteoglycans consist of a protein core to
which glycosaminoglycans (GAG) chains are
attached.
 GAG are long chains of repeating
disaccharide units consisting of a
hexosamine and uronic acid.
31
P Mark Bartold’s Biology of the Periodontal Connective
tissue

32.  They are sulfated to varying degree
1. Hyaluronan
2. Chondroitin sulfate (CS)
 Chondroitin – 4 – sulfate
 Chondroitin – 6 – sulfate
 Undersulphated chondroitin sulfate
3. Dermatan sulfate (DS) (Gibson and Pearson
1992)
1. Proteodermatan sulfate
2. Mixed hybride: DS and CS
4. Heparan sulfate
5. Heparin
6. Keratan sulfate
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

33. 33

34. 1. As matrix organizers or space fillers
 Large extracellular proteoglycans
 Small extracellular proteoglycans
2. Cell surface proteoglycans
3. Proteoglycans of hematopoietic cells
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P Mark Bartold’s Biology of the Periodontal Connective
tissue

35. Name GAG Location and interaction
Aggrecan CS/KS Cartilage
Hyaluronate
Versican CS Fibroblasts
Hyaluronate
Perlecan HS Basement membrane
Decorin DS/CS Soft connective tissue, bone,
cartilage
Collagen I & II, fibronectin,
TGF-ß
Biglycan KS Soft connective tissue, bone,
cartilage
Some matrix and cell surface
components but not with
collagen
Fibromoduline KS Collagen I
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P Mark Bartold’s Biology of the Periodontal Connective
tissue

36. Name GAG Location Function
Syndecan-1 CS/HS Epithelial cells,
fibroblasts,
lymphocytes
Cell differentiation,
receptor signal
transduction,
responsive to GF
Syndecan-2 HS Fibroblasts Cell-cell; cell matrix
interactions
Syndecan-3 HS/CS Schwann’s
cells, cartilage
Nerve cell- matrix
interaction
Syndecan-4 HS Endothelial
cells
Celll-matrix
interation
Thrombomodulin CS Vascular
epithelium
Thrombin binding
CD 44 CS/HS Surface of
hematopoietic
cells, epithelial
cells,
fibroblasts
Lymphocyte homing,
lymphocyte
endothelial
interaction
Glypican HS Fibroblasts Cell-cell, cell matrix
interaction
36
P Mark Bartold’s Biology of the Periodontal Connective
tissue

37.  Proteoglycans in PDL (Larjava et al., 1992)
1. Versican: A high molecular weight CS PG
2. Decorin : A DS PG
3. Membrane associated sulphate PG
4. 2 matrix associated herapan sulphate PG
5. 91 kDa membrane associated CS PG
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

38. 38
Ten Cate’s Oral Histology 8th edition.

39.  Present in less amount in PDL as compared
to proteoglycans and collagen.
 Detailed report by Pearson in 1982.
 Released after papain digestion of
 NaCl insoluble matrices
 Bacterial collagenase insoluble matrices
 Contain neutral sugars such as
 Mannose
 Galactose: major component
 Fucose: minor component
 Glucose: present in all tissue extract.
39
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

40.  Glycoproteins are related to:
 Cell surface
 Structural components of the connective tissue
ground substances
 Similarities:
 Procollagen contains oligosaccharides (Clark and
Kefilades, 1978)
 Elastic microfilament (Sear et al., 1977)
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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

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B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

42. 42
B K B Berkovit’s The periodontoal ligament in health
and disease, 2nd edition

43.  In PDL a higher or elevated metabolic
requirement explains the rich vasculature.
 Arterial supply:
 The blood supply is derived from the
inferior and the superior alveolar arteries
to the mandible and maxilla respectively
and reach the PDL from three sources
43
Ten Cate’s Oral Histology 8th edition.

44.  Branches in the PDL
from apical vessels that
supply the dental pulp.
 Branches from intra-
alveolar vessels.
 Branches from gingival
vessels.
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Ten Cate’s Oral Histology 8th edition.

45. 45
Ten Cate’s Oral Histology 8th edition.

46.  Venous drainage:
 The venous channels accompanying their
arterial counterparts. It receive blood
from the capillary network and also
specialized shunts called glomera.
 Lymphatic drainage:
 The flow is from the ligament toward and
into the adjacent alveolar bone. They finally
empty into larger channels.
46
Ten Cate’s Oral Histology 8th edition.

47.  The PDL has
functionally two types
of nerve fibers:
 Sensory: associated
with nociception and
mechanoception, with
touch, pressure, pain
and proprioceptive
sensations.
 Autonomic: associated
with PDL vessels.
47
Ten Cate’s Oral Histology 8th edition.

48.  The nerve fibers are either of:
 large diameter and myelinated (5-15ɥm):
pressure
 Small diameter
 Myelinated: pain
 Unmyelinated (0.5ɥm): autonomic
48
Ten Cate’s Oral Histology 8th edition.

49. Nerve endings:
A. Free endings with
treelike
configuration:
carry pain
sensation
B. Ruffini’s endings:
apical area
C. Coiled Meissner’s
endings: midroot
area
D. Encapsulated
spindle type
endings: apex area
49
Ten Cate’s Oral Histology 8th edition.

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51. 51

52. 52
Ten Cate’s Oral Histology 8th edition.

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55.  Carranza's Clinical Periodontology, 10th
edition.
 Orban’s Oral Histology and Embryology,
12th edition.
 Ten Cate’s Oral Histology 8th edition.
 B K B Berkovit’s The periodontoal
ligament in health and disease, 2nd
edition.
 P Mark Bartold’s Biology of the
Periodontal Connective tissue.
 Periodontology 2000, Vol. 3, 1993, 9-38
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