periodontium for pediatric dentistry

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3. OBJECTIVE
“What the mind doesn’t know
The eyes doesn’t see”

4. LEARNER’S OBJECTIVES
At the end of seminar Listener should be able revised with:
• Basics
• Normal features of Gingiva
• Correlation of clinical and microscopic features
• Differntiation of normal from diseased

5. Contents
• Introduction to Periodontium
• Some Basics
THE GINGIVA
• Clinical features
• Microscopic features
• Correlation of clinical and microscopic
features
• Gingival diseases in childhood

6. Introduction
It is defined as
“those tissues supporting
and investing the tooth and consists of cementum, periodontal
ligament (PDL), bone lining the alveolus (socket),
and that part of the gingiva facing the tooth”.
peri-
"around"
-odons
"tooth”
periodontium -
"around the tooth"

7. What is it ?
• Foundation
• Complex system of
tissues
• Cementum is part of it
because with bone , it
serves as a support for
the fibres of PDL

8. Periodontium – A family
Gingiva
• Proper functioning
of the periodontium is achieved
only through structural
integrity and interaction between
these various tissues.
• Together, these tissues form a
specialized fibrous joint, a
gomphosis, the components of
which are of ectomesenchymal
origin.

9. Oral mucosa
•The term mucous membrane is used to describe the moist
lining of the gastrointestinal tract, nasal passages, and
other body cavities that communicate with the exterior.
• In the oral cavity this lining is referred to as the oral
mucous membrane, or oral mucosa.
Epithelium
Lamina
propria
Mucous
Membrane

10. Epithelium
Lamina
propria
Submucosa
Periosteum
Bone
Structure
of oral
mucosa
Papillary part

12. Tonofilaments
Hemidesmosomes
Collagen Fibrils
Anchoring Fibrils
Lamina Densa
Basal Cell
Basement Membrane Complex
•The interface between the connective
tissue and the epithelium
• Basement membranes promote
differentiation. They also promote
peripheral nerve regeneration and
growth, and they tend to prevent
metastases.
•The basal lamina is made up of a
lamina lucida just below the epithelial
cells and a lamina densa beyond
the lamina lucida and adjacent to the
connective tissue

13. Classification
Masticatory
Mucosa
Lining or
Reflecting
Mucosa
Specialized
mucosa
• Gingiva
• Hard Palate
• Lip,cheek
• Soft palate
• Alveolar mucosa
• Floor of the mouth
• Dorsum of tongue
• Taste Buds

14. Hard palate
Lower lip
Gingiva
Palatine
tonsil
Pharyngeal
opening
Uvula
Anterior
faucial pillar
Underside of tongue
Sublingual duct
Sublingual gland
(under the skin)
Soft palate
Upper lip
Tongue
Anatomic locations occupied by the three main types of mucosa
in the oral cavity.

15. Structure of Oral Epithelium
• The epithelium of the oral mucous membrane is of the stratified squamous
variety.
• It may be keratinized (orthokeratinized or parakeratinized) or nonkeratinized.
•Both the keratinized and the non keratinized epithelium consists of two groups
of cells namely the keratinocytes and the non keratinocytes.
Epithelium
Keratinized
Keratinocytes
Non
Keratinocytes
Non
Keratinized
Keratinocytes
Non
Keratinocytes
Cytokeratin
Melanocytes
Langerhan Cell
Merkel Cell

16. KERATINOCYTES
These are epidermal/epithelial cell that synthesizes keratin and its
characteristic intermediate filament protein is cytokeratin.
• They show cell division.
• They undergo maturation and finally desquamate.
• They increase in volume in each successive layer from basal to superficial.
• The cells of each successive layer cover a larger area than do the cells of the layers
immediately below.

17. Keratin
•Keratin derives from Greek κερατίνη meaning "horn like"
• It is a family of fibrous structural protein
• It is the key structural material making up the outer layer of human skin.
•It is the key structural component of hair and nails, and it provides the necessary
strength and toughness for masticatory organs, such as the tongue and the hard
palate.

18. Cytokeratin
• Cytokeratins (CK) form the cytoskeleton of all epithelial cells.
• They are seen not only within the cell but also in cell contact areas like
desmosomes.
• They are termed intermediate filaments as their diameter (7–11 nm) is intermediate
between the larger microtubules (25 nm) and smaller microfilaments(4–6 nm).
Provide mechanical
linkages
Distribute the forces
over a wide area
Stress bearing structures
within the epithelial cell
Maintains cell shape
Functions

19. Classification
Type I
Basic
(1-8)
Type II
Acidic
(9-20)
•About 20 types of cytokeratin are recognized
• They always occur in pairs, of combination of type I with type II.
• In the absence of its pair, they are unstable and are susceptible
to degradation by proteases.

20. Keratinization
Determination
Differentiation
Desquamation
Maturation

21. • Orthokeratinized epithelium, represents a
complete stage of keratinization. (no nuclei in
the stratum corneum and a well-defined
stratum granulosum)
• Parakeratinized epithelium, represents an
intermediate stage of keratinization. (the
stratum corneum retains pyknotic nuclei,
stratum granulosum)
• Nonkeratinized epithelium, no keratinization.
(has neither granulosum nor corneum strata)
Degree of Keratinization

22. Keratinized
layer
Prickle cell
layer
Granular
Layer
Basal
cell
layer
Keratinized
layer
Prickle cell
layer
Basal
cell
layer
Granular layer
Basal cell
layer
Prickle cell
layer
Intermediate
layer
Superficial
layer

23. There are smaller population (10%) of cells that do not
possess cytokeratin filaments, hence they do not have
the ability to keratinize.
These group of cells are termed nonkeratinocytes.
Unlike keratinocytes, nonkeratinocytes
Non Keratinocytes
Mitotic Activity
Maturative changes or Desquamate
Arranged in layers
Desmosomal attachments with adjacent keratinocytes

24. Non Keratinocytes
Melanocytes
Langerhan cells
Merkel Cells
Inflammatory Cells
• This cells differ in appearance from other epithelial cells in having a clear halo
around their nuclei.
• Such cells have been termed clear cells, and what is obvious from ultrastructural
and immunochemical studies is that they represent a variety of cell types such as,

25. Melanocytes
Colour of oral
mucosa
Pigmentation
Melanin& Hb Melanocytes
Long dendritic
cell
Melanin as
melanosomes
Melanin
granules
Heavy
pigmentation
Melanophages

26. Melanin pigmentation of the attached gingiva in a dark-skinned
individual

27. • It is a dendritic cell sometimes seen above the basal layers of
epidermis and oral epithelium.
• It is characterized by a small rod shaped granule, called the Birbeck
granule.
• They appear in the epithelium at the same time as, or just before,
the melanocytes, and they may be capable of limited division within
the epithelium.
Langerhans Cells

28. • Unlike melanocytes, they move in and out of the epithelium, and
their source is the bone marrow.
• They have an immunologic function, recognizing and processing
antigenic material that enters the epithelium from the external
environment and presenting it to T lymphocytes.
• Langerhans cells probably can migrate from epithelium to regional
lymph nodes.
Langerhans Cells

29. Merkel Cells
• The Merkel cell is situated in the basal layer of the oral epithelium
and epidermis.
• It is not dendritic but possess keratin tonofilaments and occasional
desmosomes linking it to adjacent cells so it does not always resemble
the other clear cells in histologic sections.
• The characteristic feature of Merkel cells is the small membrane
bound vesicles in the cytoplasm, sometimes situated adjacent to a
nerve fiber associated with the cell.

30. Merkel Cells
•These granules may liberate a transmitter substance across the
synapse-like junction between the Merkel cell and the nerve fiber and
thus trigger an impulse.
•This arrangement is in accord with neurophysiologic evidence
suggesting that they are sensory and respond to touch.

31. Keratinized & Non Kertanized Epithelium
Keratinized
Surface layer
Granular
Intermediate
layer
Prickle Cell
layer
Basal layer
Keratinized
Surface layer
Granular
intermediate
Layer
Prickle cell
Layer
Basal
layer
Surface
layer
Prickle cell
Layer
Basal
layer
Intermediate
layer
Membrane
coating
Granules
Tonobrils
Tonofilaments
Glycogen
Kerato
hyaline
granules

32. Some Basics
FEATURES CELL LAYER FEATURES CELL
LAYER
Cuboidal or columnar cells
containing bundles
of tonofibrils and other cell
organelles; site of
most cell divisions.
Basal Cuboidal or columnar cells
containing separate tonofilaments
and other cell organelles; site of
most cell divisions
Basal
Larger ovoid cells containing
conspicuousTonofibril
bundle membrane-coating
granules appear in upper
part of this layer.
Prickle/Spinosum Larger ovoid cells containing
dispersed tonofilaments;
membrane-coating granules
appear in upper part of layer;
filaments become numerous
Prickle/
Spinosum
Keratinized Epithelium Non Keratinized Epithelium
Major Features of Maturation
In

33. Some Basics
FEATURES CELL
LAYER
FEATURES CELL
LAYER
Flattened cells containing conspicuous
keratohyaline granules associated
with tonofibrils; membrane coating
granules fuse with cell membrane in
upper part; internal membrane
thickening also occurs.
Granular Slightly flattened cells
containing many dispersed
tonofilaments and glycogen
Intermediate
Extremely flattened and dehydrated
cells in which all organelles have been
lost; cells filled only with packed
fibrillar material; when pyknotic
nuclei are retained, parakeratinization
occurs
Keratinized Slightly flattened cells with
dispersed
filaments and glycogen;
fewer organelles are present,
but nuclei persist
Superficial
Keratinized Epithelium Non Keratinized Epithelium
Major Features of Maturation
In

34. .
The Gingiva

35. .
“Gingiva is the part of the oral mucosa that
covers the alveolar processes of the jaws and
surrounds the necks of the teeth”.
AAP 2001 :
“The fibrous investing tissue, covered by keratinized
epithelium, that immediately surrounds a tooth and is
contiguous with its periodontal ligament and with the
mucosal tissues of the mouth.”
Definition
Glickman :

36. .
Clinical features
In an adult, normal gingiva covers the alveolar bone and tooth root to a level
just coronal to CEJ.
Anatomical Divisions
Marginal
Gingiva
Gingival
Sulcus
Attached
Gingiva
Interdental
Gingiva

37. .
Marginal Gingiva
•The marginal, or unattached, gingiva is the terminal edge or
border of the gingiva surrounding the teeth in collar like
fashion.
•After completed tooth eruption, the free gingival margin is
located on the enamel surface approximately 1.5-2 mm
coronal to the CEJ.

38. .
It’s a shallow linear depression
It demarcates the free gingiva
from adjacent attached gingiva.
It is positioned at a level
corresponding to the level of
cemento-enamel junction.
It usually it about 1 mm in wide
and presents in only 50% of cases
Free gingival groove (FGG)

39. .
Gingival Sulcus
Shallow crevice or space around the
tooth bounded by surface of tooth on
one side and the epithelium lining the
free margin of the gingiva on the other
It is roughly V –shaped.
Depth of Gingival Sulcus :
Ideal conditions - zero.
Clinically normal -2 – 3 mm.
Histologic -1.8 mm with variations from
0 to 6 mm.

40. .
Attached Gingiva
•The portion of the gingiva that is firm, dense, stippled, and tightly bound to the
underlying periosteum, tooth, and bone.
• Extends from the free gingival groove (coronally) to the mucogingival junction
(apically) where it becomes continuous with the alveolar (lining) mucosa,
except on the palate where there is no mucogingival junction.
• The width of AG is an important clinical parameter .
•It should not be confused with the width of the keratinized gingiva because the
latter also includes the marginal gingiva.

41. .
Muco Gingival Junction
• It is the junction between the soft,
fleshy mucus membrane of the oral
cavity and the tough, collagen rich
gingiva .
• The MGJ remains stationary
throughout life
• Changes in the width of the attached
gingiva are caused by modifications in
the position of its coronal portion
either by gingival overgrowth or by
gingival recession) not in the position
of MGJ.

42. Interdental Gingiva
It occupies the gingival embrasure, which is
the space beneath the area of tooth
contact.
It can be pyramidal or have a "col" shape.
The shape depends on the :
• Contact point between the two adjoining
teeth.
• The presence or absence of some degree
of recession.
•The width of the approximal tooth
surfaces

43. .
COL
The posterior teeth,have
approximal contact surfaces rather
than contact point.
The interdental papilla has a shape
in conformity with the outline of
the interdental contact surfaces, a
concavity hence a COL- is
established in the posterior
tooth.
The COL region is covered by thin
non-keratinized epithelium.
Col
Col

44. .
In Health & Disease

45. Microscopic Features Of Gingiva

46. Microscopic
Features
Epithelium
Oral Sulcular Junctional
Connective Tissue
Collagen,fibers
(60%) , fibroblasts
(5%), .
Vessels,
nerves,matrix
(35%).

47. Gingival Epithelium
• Historical Perspective -
Only a physical barrier to infection and the underlying gingival
attachment.
• Current Belief and Example -
An active role in innate host defense.
Eg. Responds to bacteria by
 increased proliferation
 alteration of cell-signaling events
 changes in differentiation and cell death
 alteration of tissue homeostasis
•Types

48. Mechanical, chemical, water, and microbial barrier
Signaling functions
Cell-cell attachments
Basal lamina
Keratin cytoskeleton
Keratinocyte
Langerhans cells
Melanocytes, Merkel cells
Constant Renewal
Replacement of damaged cells
Cell-Cell Attachments
Desmosomes, adherens junctions
Tight junctions, gap junctions
Cell–Basal Lamina
Synthesis of basal lamina components
Hemidesmosome
Functions and Features of Gingival Epithelium
Functions
Architectural Integrity
Major Cell Type
OtherCell Type
Constant Renewal
Cell - Cell attachments
Cell – Basal Lamina

49. Oral {Outer} Epithelium
• The oral, or outer, epithelium covers the crest and outer surface of the
marginal gingiva and the surface of the attached gingiva.
• On average, the oral epithelium is 0.2-0.3 mm in thickness.
Features:
•Represents the keratinized gingiva
•Extends from mucogingival junction to gingival margin
•It may be ortho- or para- keratinized, however the prevalent surface is
parakeratinized.

50. Sulcular Epithelium
• It lines the gingival sulcus and is thin,
nonkeratinized stratified squamous epithelium
without rete pegs.
• Extent - from the coronal limit of the junctional
epithelium to the crest of the gingival margin.
Potential to keratinize if........
• If it is reflected and exposed to oral cavity.
• The bacterial flora of sulcus is totally eliminated.

51. Sulcular Epithelium
• The outer epithelium loses its keratinization
when placed in contact with tooth.
• The sulcular epithelium is extremely
important because it may act as a semi
permeable membrane.
• Through which injurious bacterial products
pass into the gingival and tissue fluid from
the gingiva seeps into the sulcus.

52. Junctional Epithelium
• It is an epithelial collar that surrounds the tooth.
• Extent – CEJ---Bottom of gingival crevice
• Length- 0.25 to 1.35
• Coronally – 15-30 cells thick
• Apically – Narrows to 1-3 cell thick
• These cells can be grouped in two strata:
Basal layer- facing the connective tissue
Suprabasal layer- extending to the tooth surface.

53. • The JE attaches to afibrillar cementum present
on the crown (usually restricted to an area
within 1 mm of the CEJ) and root cementum in
a similar manner.
• The attachment of the JE to the tooth is
reinforced by the gingival fibers, which brace
the marginal gingiva against the tooth surface.
For this reason, the JE and the gingival fibers
are considered a functional unit, referred to as
the dentogingival unit

54. • The junctional epithelium is formed by the
confluence of the oral epithelium and the
reduced enamel epithelium during tooth
eruption.
• After enamel formation is complete, the enamel
is covered with reduced enamel epithelium (REE),
which is attached to the tooth by a basal lamina
and hemidesmosomes.
• When the tooth penetrates the oral mucosa, the
REE unites with the oral epithelium and
transforms into the JE.
Development

55. Development

56. • As the tooth erupts, this united epithelium
condenses along the crown, and the
ameloblasts, which form the inner layer of
the REE, gradually become squamous
epithelial cells.
• The transformation of the REE into a
junctional epithelium proceeds in an apical
direction without interrupting the attachment
to the tooth.
• According to Schroeder and Listgarten,this
process takes between 1 and 2 years
Development

57. Principal Features
• The cells of JE immediately adjacent to the
tooth, attach themselves to the tooth by
hemidesmosomes and basal lamina.
• JE is Unique in having to basal lamina
1. Internal
2. External
Hemi
desmosomes
Basal
lamina
Attachment
appratus

58. Junctional Epithelium
Enamel
Hemidesmosomes
Desmosomes
Gap Junction
Basal lamina
(internal)
Basal lamina
(external)
Lamina
Propria

59. Principal Features
• The JE has a high turnover rate (in the order
of 1-6 days) and its cells are exfoliated
coronally into the gingival crevice.
• It is highest of any oral mucosa.
• Rapid shedding of cells effectively removes
bacteria adhering to the epithelial cells and
therefore is an important part of the
antimicrobial defense mechanisms at the
dentogingival junction.

60. Principal Features

61. Principal Features
• Cells of JE together with fibroblast and
endothelial cells express ICAM – 1
• ICAM -1 helps in transmigration of
neutrophils from adjacent capillaries and
through junctional epithelium.
• Expresses –
K 19 (absent from keratinized epithelium)
K5 & K14 (stratification specific)

62. Conclusion
• In conclusion, it is usually accepted that the JE exhibits
several unique structural and functional features that
contribute to preventing pathogenic bacterial flora from
colonizing the subgingival tooth surface.
1. JE is firmly attached to the tooth surface, forming an
epithelial barrier against plaque bacteria.
2. It allows access of gingival fluid, inflammatory cells, and
components of the immunologic host defense to the gingival
margin.
3. Junctional epithelial cells exhibit rapid turnover, which
contributes to the host-parasite equilibrium and rapid repair
of damaged tissue.
4. The cells of the junctional epithelium have an endocytic
capacity equal to that of macrophages and neutrophils and
that this activity might be protective in nature.

63. Gingival fibers
• The connective tissue of the marginal gingiva is
densely collagenous, containing a prominent
system of collagen fiber bundles called the gingival
fibers. They consist of type I collagen.
Functions:
1. To brace the marginal gingiva firmly against the
tooth.
2. To provide the rigidity necessary to withstand the
forces of mastication without being deflected away
from the tooth surface.
3. To unite the free marginal gingiva with the
cementum of the root and the adjacent attached
gingiva.

64. Gingival fibers
• They are arranged in three different
groups
Gingivo
dental
Circular
Gingival
Fibers
Transseptal

65. Gingivodental Group
• The gingivodental fibers are those on the
facial, lingual, and interproximal surfaces.
They are embedded in the cementum just
beneath the epithelium at the base of the
gingival sulcus.
• On the facial and lingual surfaces, they
project from the cementum in fanlike
conformation toward the crest and outer
surface of the marginal gingiva, terminating
short of the epithelium

66. Gingival fibers
Gingivodental
Group

67. Gingivodental Fibers
• They also extend externally to the
periosteum of the facial and lingual
alveolar bones, terminating in the
attached gingiva or blending with the
periosteum of the bone.
• Interproximally, the gingivodental fibers
extend toward the crest of the
interdental gingiva.

68. Circular Fibers
• The circular fibers course through the
connective tissue of the marginal and
interdental gingiva and encircle the tooth in
ringlike fashion.
Circular Group

69. Transseptal Group
• Located interproximally, the transseptal
fibers form horizontal bundles that extend
between the cementum of approximating
teeth into which they are embedded.
• They lie in the area between the epithelium
at the base of the gingival sulcus and the
crest of the interdental bone
• They are sometimes classified with the
principal fibers of the periodontal ligament.

70. Transseptal Group
Transseptal Group

71. Gingival fibers
• Page et al also have described
A group of semicircular fibers that attach at
the proximal surface of a tooth, immediately
below the cementoenamel junction, go
around the facial or lingual marginal gingiva
of the tooth, and attach on the other
proximal surface of the same tooth

72. Gingival fibers
H – Transgingival G - Semicircular

73. Gingival fibers
• Page et al also have described
A group of transgingival fibers that attach
in the proximal surface of one tooth,
traverse the interdental space diagonally, go
around the facial or lingual surface of the
adjacent tooth, again traverse diagonally the
interdental space, and attach in the proximal
surface of the next tooth.

74. • Supraperiosteal arterioles along the facial
and lingual surfaces of the alveolar bone,
from which capillaries extend along the
sulcular epithelium and between the rete
pegs of the external gingival surface.
• Occasional branches of the arterioles pass
through the alveolar bone to the periodontal
ligament or run over the crest of the alveolar
bone
Blood Supply

75. Blood Supply
• Vessels of the periodontal ligament, which
extend into the gingiva and anastomose
with capillaries in the sulcus area.
• Arterioles, which emerge from the crest of
the interdental septa and extend parallel to
the crest of the bone to anastomose with
vessels of the periodontal ligament, with
capillaries in the gingival crevicular areas
and vessels that run over the alveolar crest.

76. Lymphatics
• Role of the lymphatic system in removing
excess fluids, cellularand protein debris,
microorganisms, and other elements is
important in controlling diffusion and the
resolution of inflammatory processes.
• The lymphatic drainage of the gingiva
brings in the lymphatics of the connective
tissue papillae.

77. Lymphatics
• It progresses into the collecting network
external to the periosteum of the alveolar
process, then 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.

78. Nerve Supply
• Neural elements are extensively distributed
throughout the gingival tissues.
• Within the gingival connective tissues, most
nerve fibers are myelinated and are closely
associated with the blood vessels.
• Gingival innervation is derived from fibers
arising from nerves in the periodontal
ligament and from the labial, buccal, and
palatal nerves.

79. Nerve Supply
The following nerve structures are present in
the connective tissue:
• A meshwork of terminal argyrophilic fibers,
some of which extend into the epithelium
• Meissner-type tactile corpuscles
• Krause-type end bulbs, which are
temperature receptors
• encapsulated spindles.

80. CORRELATION OF CLINICAL
AND
MICROSCOPIC FEATURES

81. Color
• The color of the attached and marginal
gingiva is generally described as “coral pink”
Produced by
• vascular supply
• the thickness and degree of keratinization of
the epithelium
• presence of pigment-containing cells.

83. Size
• The size of the gingiva corresponds with
the sum total of the bulk of cellular and
intercellular elements and their vascular
supply.
• Alteration in size is a common feature of
gingival disease.

84. Contour
The contour or shape of the gingiva varies
considerably and depends upon
• shape of the teeth and their alignment in
the arch
• location and size of the area of proximal
contact
• the dimensions of the facial and lingual
gingival embrasures.

85. Contour
• The marginal gingiva envelops the teeth in
collarlike fashion and follows a scalloped
outline on the facial and lingual surfaces.
• It forms a straight line along teeth with
relatively flat surfaces.
• Labio version - the normal arcuate contour is
accentuated, and the gingiva is located
farther apically.
• Lingual version - the gingiva is horizontal and
thickened

86. Shape
The shape of the interdental gingiva is
governed by the
• contour of the proximal tooth surfaces
• the location and shape of gingival
embrasures.

87. Consistency
• It is firm and resilient and with the exception
of the movable free margin, tightly bound to
the underlying bone.
• The collagenous nature of the lamina
propria and its contiguity with the
mucoperiosteum of the alveolar bone
determine the firmness of the attached
gingiva.
• The gingival fibers contribute to the firmness
of the gingival margin.

88. Surface texture
• The gingiva presents a textured surface
similar to an orange peel and is referred to
as being stippled.
• Stippling is best viewed by drying gingiva.
• The attached gingiva is stippled; the
marginal gingiva is not.

89. Surface texture
• The attached gingiva is stippled; the
marginal gingiva is not.
• Stippling is less prominent on lingual than
facial surfaces.
Stippling varies with age-
• In infancy - Absent
• Appears in some children at about 5 years of
age, increases until adulthood
• Frequently begins to disappear in old age.

90. Surface texture
• Microscopically, stippling is produced by
alternate rounded protuberances and
depressions in the gingival surface.
• The papillary layer of the connective tissue
projects into the elevations.
• The elevated and depressed areas are
covered by stratified squamous epithelium.

91. Surface texture
• Stippling is a form of adaptive specialization
or reinforcement for function.
• It is a feature of healthy gingiva, and
reduction or loss of stippling is a common
sign of gingival disease.
• When the gingiva is restored to health after
treatment, the stippled appearance returns.

92. Position
• The position of the gingiva refers to the level
at which the gingival margin is attached to
the tooth.
• When the tooth erupts into the oral cavity,
the margin and sulcus are at the tip of the
crown,as eruption progresses, they are seen
closer to the root.
• Continuous Tooth Eruption
• Active Eruption
• Passive Eruption

93. Passive Eruption

94. Click to edit Master title style
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95. • The tissues are pale pink but to a lesser degree
than the attached gingiva of adults because the
thinness of the keratinized layer causes the
underlying vessels in children to be more visible.
• Stippling
• Gingival sulcular depth is shallower in the primary
dentition than in the permanent dentition.
• Mean sulcus depth is 2.1 mm(±0.2mm), with an
increase in depth from anterior to posterior.
PERIODONTIUM OF THE
PRIMARY DENTITION

96. • The interdental gingiva is broad buccolingually and
narrow mesiodistally, consistent with the
morphology of the primary dentition.
• The attached gingiva varies in width
anteroposteriorly, widest in the incisor area,
narrowing over cuspid, and widening over molars
• The lingual attached gingiva shows an inverse
relationship
• Interestingly, the JE is thicker in the primary
dentition than in the permanent dentition, which is
a phenomenon thought to reduce the permeability
of the epithelium to bacterial toxins.

97. • The interdental gingiva is broad
buccolingually & narrow mesiodistally,
consistent with the morphology of the
primary dentition.
• The attached gingiva varies in width
anteroposteriorly, widest in the incisor
area, narrowing over cuspid, and
widening over molars.
• The lingual attached gingiva shows an
inverse relationship.

98. • Radiographically, the lamina dura is prominent in the
primary dentition, with a wider periodontal space
than in the permanent dentition.
• The marrow spaces of the bone are larger, and the
crests of the interdental bony septa are flat, with
bony crests within 1 to2 mm of the CEJ.

99. Periodontium – A family
Gingiva
• Proper functioning
of the periodontium is achieved
only through structural
integrity and interaction between
these various tissues.
• Together, these tissues form a
specialized fibrous joint, a
gomphosis, the components of
which are of ectomesenchymal
origin.

100. Contents
Periodontal Ligament
• Introduction
• Periodontal Fibers
• Cellular Elements
• Ground Substance
• Functions
Cementum
• Introduction
• Classification
• Thickness
• Resorption & Repair

101. “Sometimes when I consider
what tremendous
consequences come from little
things…
I am tempted to think….
there are no little things”.

102. Periodontal Ligament
Introduction
• It is dense fibrous connective tissue that
occupies the periodontal space between
root of the teeth and the alveolus.
• It has continuity with gingiva, pulp.
• Average width - 0.25mm
• The space represents hour glass in shape

103. Periodontal fibers
• The most important
elements of the
periodontal ligament are
the principal fibers,
which are collagenous.
• They arranged in
bundles, and follow a
wavy course.
• Terminal portions of the
principal fibers that
insert into cementum
and bone are termed
Sharpey's fibers.

104. Collagen microfibrils, fibrils, fibers,
and bundles

105. Principal Fibers
Trans
septal
Alveolar
crest
Horizontal Oblique
Apical
Inter
radicular

106. Trans septal
Alveolar Crest
Horizontal
Inter radicular
Oblique
Apical

107. Transseptal Group
• They extend interproximally over the
alveolar bone crest and are embedded in the
cementum of adjacent teeth.
• They are a remarkably constant finding and
are reconstructed even after destruction of
the alveolar bone has occurred in
periodontal disease.
• These fibers may be considered as belonging
to the gingiva because they do not have
osseous attachment.

108. Alveolar crest Group
• Alveolar crest fibers extend obliquely from
the cementum just beneath the JE to the
alveolar crest.
• Fibers also run from the cementum over the
alveolar crest and to the fibrous layer of the
periosteum covering the alveolar bone.

109. Alveolar crest Group
• They prevent the extrusion of the tooth and
resist lateral tooth movements.
• Their incision does not significantly increase
tooth mobility unless significant attachment
loss has occurred.

110. Horizontal Group
• Horizontal fibers extend at right angles to
the long axis of the tooth from the
cementum to the alveolar bone.

111. • They are the largest group in the PDL, extend
from the cementum in a coronal direction
obliquely to the bone.
• They bear the brunt of vertical masticatory
stresses and transform them into tension on
the alveolar bone.
Oblique Group

112. Apical Group
• The apical fibers radiate in a rather irregular
fashion from the cementum to the bone at
the apical region of the socket.
• They do not occur on incompletely formed
roots

113. • They are the largest group in the PDL, extend
from the cementum in a coronal direction
obliquely to the bone.
• They bear the brunt of vertical masticatory
stresses and transform them into tension on
the alveolar bone.
Interradicular Group

114. Connective tissue Cells
Epithelial rest cells
Immune system cells
Cells associated with
neuro vascular elements
Cellular Elements

115. Connective
tissue cells
Fibroblast Cementoblast Osteoblast
Connective tissue cells

116. Fibroblast
• Fibroblasts are the most common cells in the
PDL
• It appear as ovoid or elongated cells
oriented along the principal fibers and
exhibiting pseudopodia like processes.
• These cells synthesize collagen and also
possess the capacity to phagocytose "old"
collagen fibers and degrade them by enzyme
hydrolysis.

117. Fibroblast
• Thus collagen turnover appears to be
regulated by fibroblasts in a process of
intracellular degradation of collagen not
involving the action of collagenase.
• Phenotypically distinct and functionally
different subpopulations of fibroblasts exist
in the adult periodontal ligament.

118. Fibroblast
• Thus collagen turnover appears to be
regulated by fibroblasts in a process of
intracellular degradation of collagen not
involving the action of collagenase.
• Phenotypically distinct and functionally
different subpopulations of fibroblasts exist
in the adult periodontal ligament.

119. EPITHELIAL CELLS
• The epithelial cells in the PDL are remnants
of HERS, known as the epithelial cell rests of
Malassez.
• The epithelial cells occur close to the
cementum as clusters or strands of cells
easily recognized in histologic sections
because their nuclei generally stain deeply.
• Some believe they form a network around
roots that possibly interconnects with the
junctional epithelium

120. EPITHELIAL CELLS

121. UNDIFFERENTIATED MESENCHYMAL CELL
• It is an important cellular constituent of the
PDL
• These cells have a perivascular location.
• They have been demonstrated to be a source
of new cells for the PDL.

122. • Whether a single progenitor cell gives rise to
daughter cells that differentiate into
fibroblasts, osteoblasts, and cementoblasts
or whether separate progenitors exist for
each cell line is not known.
• The fact that new cells are being produced for
the PDL while cells of the ligament are in a
steady state means that this production of
new cells must be balanced by migration of
cells out of the ligament or cell death.

123. Ground substance
Ground
substance
Glycosamino
glycans
Proteoglycans Hyaluronic
acid
Glycoprotein
Fibronectin laminin

124. Ground substance

125. Functions
Physical
Formative &
Remodelling
Nutritional
&
Sensory
Regulation
of
PDL width

126. Physical Functions
l. Provision of a soft tissue "casing" to protect the
vessels and nerves from injury by mechanical
forces
2. Transmission of occlusal forces to the bone
3. Attachment of the teeth to the bone
4. Maintenance of the gingival tissues in their
proper relationship to the teeth
5. Resistance to the impact of occlusal forces
(shock absorption)

127. Physical Functions

128. Cementum
Introduction
• Cementum is the calcified
avascular mesenchymal tissue that
forms the outer covering of the
anatomic root.
• The two main types of cementum
are acellular (primary) and cellular
(secondary) cementum .
• Both consist of a calcified
interfibrillar matrix and collagen
fibrils.

129. • The two main sources of collagen fibers in
cementum are Sharpey's (extrinsic) fibers,
which are the embedded portion of the
principal fibers of the periodontal ligament.
• They are formed by the fibroblasts
• Fibers that belong to the cementum matrix
per se (intrinsic) and are produced by the
cementoblasts.

130. • Organic matrix – Type – I (90%) Collagen
Type – III (5%) Collagen
• The inorganic content of cementum
(hydroxyapatite) is 45% to 50%
• It is less than that of bone (65%), enamel
(97%), or dentin (70%).'

131. Acellular Cementum
• It is the first to be
formed and covers
approximately the
cervical third or half
of the root
• It does not contain
cells.

132. Acellular Cementum
• This cementum is formed before the tooth
reaches the occlusal plane, and its thickness
ranges from 30 to 230µm
• Sharpey‘s fibers comprise most of the
structure of acellular cementum,which has
a principal role in supporting the tooth

133. Cellular Cementum
• It is formed after the tooth reaches the
occlusal plane
• It is more irregular and contains cells
(cementocytes)
• They are present in individual spaces
(lacunae) that communicate with each
other through a system of anastomosing
canaliculi

134. Cellular Cementum
• Cellular cementum
is less calcified than
the acellular type
• Sharpey's fibers
occupy a smaller
portion of cellular
cementum

135. Classification
• Acellular afibrillar cementum (AAC)
• It contains neither cells nor extrinsic or
intrinsic collagen fibers, apart from a
mineralized ground substance.
• It is a product of cementoblasts and is found
as coronal cementum in humans.
• It has a thickness of 1 to 15 µm.

136. Classification
• Acellular extrinsic fiber cementum (AEFC)
• It is composed almost entirely of densely
packed bundles of Sharpey's fibers and lacks
cells.
• It is a product of fibroblasts and
cementoblasts and is found in the cervical
third of roots in humans but may extend
further apically.
• Its thickness is between 30 and 230 µm.

137. Classification
• Cellular mixed stratified cementum (CMSC)
• It is composed of extrinsic (Sharpey's) and
intrinsic fibers and may contain cells.
• It is a co-product of fibroblasts and
cementoblasts.
• It appears primarily in the apical third of the
roots and apices and in furcation areas.
• Its thickness ranges from 100 to 1000 µm.

138. Classification
• Cellular intrinsic fiber cementum (CIFC)
• It contains cells but no extrinsic collagen
fibers.
• It is formed by cementoblasts,
• Intermediate cementum is an ill-defined zone
near the cementodentinal
• junction of certain teeth that appears
• to contain cellular remnants of Hertwig's
sheath embedded
• in calcified ground substance

139. Classification
• Intermediate cementum
• It is an ill-defined zone near the
cementodentinal junction of certain teeth
that appears to contain cellular remnants of
Hertwig's sheath embedded in calcified
ground substance

140. Classification
• Intermediate cementum
• It is an ill-defined zone near the
cementodentinal junction of certain teeth
that appears to contain cellular remnants of
Hertwig's sheath embedded in calcified
ground substance.

141. Thickness of cementum
• Cementum deposition is a continuous
process that proceeds at varying rates
throughout life.
• The thickness of cementum on the coronal
half of the root varies from 16 to 60 µm, or
about the thickness of a hair.
• It attains its greatest thickness (up to 150 to
200 µm) in the apical third and in the
furcation areas.

142. Thickness of cementum
• It is thicker in distal surfaces than in mesial
surfaces, probably because of functional
stimulation from mesial drift over time.
• Between the ages of 11 and 70, the average
thickness of the cementum increases
threefold, with the greatest increase in the
apical region.
• Average thicknesses of 95 µm at age 20 and
215µm at age 60 have been reported.

143. Abnormality in the Thickness
• Absence or paucity – Aplasia/ hypoplasia
• Excess – Hyperplasia / hypercementosis.

144. Hypercementosis
• Because of considerable physiologic
variation in the thickness of cementum
among different teeth in the same person
and also among different persons,
distinguishing between hypercementosis
and physiologic thickening of cementum is
sometimes difficult.

145. Hypercementosis
• The term
hypercementosis
refers to a prominent
thickening of the
cementum.
• It may be localized to
one tooth or affect
the entire dentition.

146. Hypercementosis
• Hypercementosis occurs as a generalized
thickening of the cementum, with nodular
enlargement of the apical third of the root.
• It also appears in the form of spike like
(cemental spikes) created by either the
coalescence of cementicles that adhere to
the root or the calcification of periodontal
fibers at the sites of insertion into the
cementum

147. Hypercementosis
• The etiology of hypercementosis varies and
is not completely understood.
• The spikelike type of hypercementosis
generally results from excessive tension from
orthodontic appliances or occlusal forces.
• The generalized type occurs in a variety of
circumstances.

148. Hypercementosis
• In teeth subject to low-grade periapical
irritation arisingfrom pulp disease, it is
considered compensation for the destroyed
fibrous attachment to the tooth.
• The cementum is deposited adjacent to the
inflamed periapical tissue.
• Hypercementosis of the entire dentition may
occur in patients with Paget's disease.

149. Resorption and Repair
• Permanent teeth do not undergo physiologic
resorption as do primary teeth.
• However, the cementum of erupted as well
as unerupted teeth is subject to resorptive
changes that may be of microscopic
proportion
• It may be sufficiently extensive to present a
radiographically detectable alteration in the
root contour.

150. Causes
• Resorption may be caused by local or
systemic causes or may occur without
apparent etiology.
Local conditions
• trauma from occlusion orthodontic
movement
• pressure from malaligned erupting teeth
• cysts and tumors
• teeth without functional antagonists
• embedded teeth
• replanted and transplanted teeth
• periapical disease and periodontal disease.

151. Causes
Systemic conditions
• calcium deficiency,
• hypothyroidism,
• hereditary fibrous osteodystrophy,
• Paget's disease.

152. .

153. Conclusion

154. Click to edit Master title style
Click to edit Master subtitle style

156. Periodontium – A family
Gingiva
• Proper functioning
of the periodontium is achieved
only through structural
integrity and interaction between
these various tissues.
• Together, these tissues form a
specialized fibrous joint, a
gomphosis, the components of
which are of ectomesenchymal
origin.

157. Contents
Alveolar process
• Introduction
• Composition
• Structure
• Vascular supply
• Clinical Considerations
• Conclusion
• References

158. Introduction
• The alveolar process is the portion of the maxilla
and mandible that forms and supports the tooth
sockets (alveoli).
• It forms when the tooth erupts to provide the
osseous attachment to the forming PDL.
• It disappears gradually after the tooth is lost.
• Tooth dependent bony structure.

159. Composition
Inorganic Matter
• Calcium & phosphate
• Hydroxyl, carbonate, citrate
• Trace amount of sodium, magnesium,
flourine
Organic Matrix (osteoid)
• Collagen type I
• Non collagenous protein

160. Inorganic matter
• The inorganic part of bone is made of bone minerals.
• The mineral component is composed of hydroxyapatite
crystals, with carbonate content and low Ca/P ratio than
the pure hydroxyapatite.
• Small amounts of calcium phosphate are also present.
• Bone crystals are in the form of thin plates or leaflike
structures.
• They are packed closely with long axis nearly parallel to
collagen fibrils axis.

161. Inorganic matter
• The narrow gaps between the crystals contain
associated water and organic macromolecules.
• The ions present are calcium phosphate, hydroxyl
and carbonate
• Citrate, magnesium, sodium, potassium, fluoride,
iron, zinc, copper, aluminum, lead, strontium, silicon
and boron are present in small quantities.

162. Organic matrix
• Collagen is the major organic component in
mineralized bone tissues.
• Type I collagen (> 95%) is the principal collagen in
mineralized bone and, together with type V collagen
(< 5%), forms heterotypic fiber bundles
• This provide the basic structural integrity of
connective tissues.
• The elasticity of collagen imparts resiliency to the
tissue and helps to resist fractures.

163. Collagens
• Type I
• Type III
• Type V
• Type XII
Alveolar
Bone
• Type I
• Type IIISharpey’s
fibers

164. Non Collagenous Proteins
Matrix Gla protein
Proteoglycans
Osteonactin
Osteopontin and
Bone sialoprotein
Osteocalcin

165. Osteocalcin
• It is the first noncollagenous protein to be
recognized and represents less than 15% of the
noncollagenous bone protein.
• Also known as bone Gla protein as it contains the
amino acid γ-carboxy glutamic acid.
• It is a glycoprotein secreted by osteoblasts and is
regulated by vitamin D3 and parathyroid hormone.

166. Osteopontin & bone sialoprotein
Similarities
Heavily glycosylated and phosphorylated
Expression of both is stimulated by TGF-ᴃ & glucocorticoids
Sialoprotein Osteopontin
Glutamic acid is predominant Aspartate is predominant
Restricted to mineralizing tissue Generalized distribution
Function in initiation of mineral
crystal formation
Potent inhibitor of hydroxypatite
crystal growth
Transcription is supressed by
vitamin D3
Transcription is upgraded by by
vitamin D3
Differences

167. Osteonectin
• It comprises about 25% of noncollagenous proteins.
• It is bound to collagen and hydroxyapatite crystals.
• It is a secreted calcium binding glycoprotein
• It interacts with extracellular matrix molecules.
Plays a role in:
• the regulation of cell adhesion, proliferation
• modulation of cytokine activity,
• in initiating hydroxyapatite crystal formation.

168. Proteoglycans
• There are three types present
1. A large chondroitin sulfate proteoglycan
2. Biglycan and decorin
(chondroitin sulfate proteoglycan I and II respectively)
3. A small chondroitin sulfate proteoglycan
• Decorin and biglycan comprise < 10% of the
noncollagenous proteins in bone, but this decreases
with maturation of bone.

169. Proteoglycans
Biglycan
• It is more prominent in developing bone and has
been mineralized to pericellular areas.
• It’s precise function is unknown, but similar to
decorin, it can bind TGF-β and extracellular matrix
macromolecules, including collagen, and thereby
regulate fibrillogenesis.

170. Proteoglycans
Decorin
• It binds mainly within the gap region of collagen
fibrils and decorates the fibril surface.
• The primary calcification in bones is reported to
follow removal of decorin and fusion of collagen
fibrils

171. Cells
Osteoblasts
Osteoclasts
Osteocytes

172. Osteoblast
• Mononucleated
• Synthesis and
secrete macro
molecular organic
constituents of
bone matrix
• Derived from osteo
progenitor cells of
mesenchymal
origin
Osteoblast
Osteocyte
Osteoclast

173. Functions
• Formation of new bone
• Regulation of bone remodeling
• Mineral metabolism
• Role in mineralization of osteoid
• Secretes type I collagen

174. Functions
• Also secrete non collagenous protein in
small amount
• Receptor of various hormone including PTH,
vitamin D3,estrogen and glucocorticoids
• Recognizes the resorptive signal and
transmit it to the osteoclast

175. Osteocytes
• Osteoblasts produce the
extracellular matrix,
osteoid.
• As they form the matrix
they get entrapped within
the matrix they secrete,
and are called osteocytes.
• The number of osteoblasts
that become osteocytes,
depends on the rapidity of
bone formation.
Osteocyte
Osteoblast
Osteoid

176. Osteocytes
• Within the bone matrix, the osteocyte
reduces in size, creating a space around it,
called the osteocytic lacuna.
• The lacunae can appear ovoid or flattened.
• Narrow extensions of these lacunae form
channels called canaliculi.

177. Osteocytes
• The canaliculi penetrate the bone matrix
and permit diffusion of nutrients, gases and
waste products between osteocytes and
blood vessels.
• Osteocytes also sense the changes in
environment and send signals that affect
response of other cells involved in bone
remodeling.

178. Osteocytes
• This interconnecting system maintains the
bone integrity and bone vitality.
• Failure of the interconnecting system
between osteocytes and osteoblasts leads
to sclerosis and death of bone.

179. Osteoclast
• The word “osteoclast” is derived from the
Greek words for “bone and broken”.
• It lies in resorption bays called Howship’s
lacunae.
• Variable in shape
• 40-100µm in diameter
• 15-20 packed nuclei
Osteoclast

180. Structure
1. An external plate of
cortical bone
2. The inner socket wall
of thin, compact
bone called the
alveolar bone
proper, which is seen
as the lamina dura in
radiographs and is
formed by the
cancellous bone.

181. Structure
3. Cancellous trabeculae, between these two
compact layers, which act as supporting
alveolar bone.
• The interdental septum consists of
cancellous supporting bone enclosed within
a compact border

182. Relative proportions of cancellous bone and compact bone in a
longitudinal faciolingual section

183. Socket Wall
• The socket wall consists of dense,
lamellated bone and bundle bone.
• Bundle bone is the term given to bone
adjacent to the PDL that contains a great
number of Sharpey's fibers.

184. Socket Wall
Characteristics:
• thin lamellae arranged in layers parallel to
the root
• intervening appositional lines.
• Bundle bone is localized within the alveolar
bone proper.

185. Bone Marrow
• In the embryo and newborn, the cavities of all
bones are occupied by red hematopoietic marrow.
• The red marrow gradually undergoes a physiologic
change to the fatty or yellow inactive type of
marrow.
• In the adult, the marrow of the jaw is normally of
the fatty type.
• Red marrow is found in the ribs,
sternum,vertebrae, skull, and humerus.

186. Bone Marrow
• However, foci of red bone marrow are occasionally
seen in the jaws, often accompanied by resorption
of bony trabeculae.
Common locations are
• the maxillary tuberosity,
• the maxillary and mandibular molar and premolar
areas.
• mandibular symphysis and ramus angle
• It may be visible radiographically as zones of
radiolucency.

187. Periosteum & Endosteum
Periosteum:
• Tissue covering the outer surface of bone.
• Inner layer - osteoblasts surrounded by
osteoprogenitor cells.
• Outer layer – blood vessels and nerves, collagen
fibers and fibroblasts.
Endosteum:
• Tissue lining the internal bone cavities.
• Composed of single layer of osteoblasts and small
layer of connective tissue.
• Inner layer – osteogenic
• Outer layer- fibrous layer

188. Vascular Supply
• The blood supply to the supporting structures of
the tooth is derived from the inferior and superior
alveolar arteries to the mandible and maxilla
respectively.
It reaches the periodontal ligament from three
sources:
• apical vessels,
• penetrating vessels from the alveolar bone,
• and anastomosing vessels from the gingva

189. Vascular Supply
• The vascular supply to the bone enters the
interdental septa through nutrient canals together
with veins, nerves, and lymphatics.
• Dental arterioles, which also branch off the
alveolar arteries, send tributaries through the PDL,
and some small branches enter the marrow spaces
of the bone through the perforations in the
cribriform plate.
• Small vessels emanating from the facial and lingual
compact bone also enter the marrow and spongy
bone.

190. Lymphatic drainage
• Lymphatics supplement venous drainage system.
• Those draining the region just beneath the
junctional epithelium pass into the periodontal
ligament and accompany the blood vessels into the
periapical region
• From PDL, lymphatic channels pass through
alveolar bone to inferior dental canal in mandible
or infraorbital canal in the maxilla then to
submaxillary lymph nodes.

191. Clinical Considerations
Orthodontic tooth Movement
• Bone, although one of the hardest tissues of the
human body, is biologically a highly plastic tissue.
• Where bone is covered by a vascularized
connective tissue.
• It is exceedingly sensitive to pressure, whereas
tension acts generally as a stimulus to the
production of new bone.

192. Clinical Considerations
Orthodontic tooth Movement
• It is this biologic plasticity that enables the
orthodontist to move teeth without disrupting their
relations to the alveolar bone.
• Bone is resorbed on the side of pressure and
apposed on the side of tension,thus the entire
alveolus is allowed to shift with the tooth.

193. Increase in the level of c Amp on
pressure side
At the site of compression, osteoclast
proliferate and there is initial resoprtion of
bone
the initial response may involve osteoblasts
which can produce collagenolytic enzymes to
remove a portion of unmineralized extracellular
matrix, facilitating access of osteoclast
precursors to bone surface.
At sites of tension, osteoblasts are
activated to produce osteoid that
subsequently mineralizes to form new
bone.

195. • Fusion of the cementum and alveolar bone with
obliteration of the periodontal ligament is
termed ankylosis.
• Ankylosis occurs in teeth with cemental
resorption, which suggests that it may represent
a form of abnormal repair.
• Ankylosis results in resorption of the root and its
gradual replacement by bone tissue.
• For this reason, reimplanted teeth that ankylose
will lose their roots after 4 to 5 years and
exfoliate.
Ankylosis

196. • In healthy patients, abundant
PDL fibroblasts block
osteogenesis within the
periodontium by releasing
locally acting regulators, such
as cytokines and growth
factors, thereby maintaining
separation of tooth root from
alveolar bone.
• Necrosis of the periodontal
ligament’s cellular elements
by desiccation, crushing or
mechanical damage, as in
severe luxation injury,
disrupts this normal
homeostatic mechanism.
Ankylosis in replantation

197. • Ankylosis is established not only via inflammatory-
mediated and mechanical alterations in the
periodontal ligament, but also because insufficient
functional cellular elements survive to suppress
osteogenic activity.
• This disruption allows growth of bone across the
periodontal ligament and ankylosis
• Ankylosis is most common following delayed
replantation or severe intrusion .
Ankylosis in replantation

198. • With the loss of periodontal ligament homeostasis
and subsequent ankylosis, replacement resorption
ensues.
• The root is gradually replaced by bone as part of
normal turnover of the body’s skeletal mass.
• In the young child, the combined effect of a higher
metabolic rate that promotes replacement
resorption and the lack of root mass in the
immature tooth produces tooth loss within a few
years.
Ankylosis in replantation

199. Ankylosis
• When titanium implants are placed in the
jaw, healing results in bone formed in direct
apposition to the implant without any
intervening connective tissue.
• This may be interpreted as a form of
ankylosis.
• Because resorption of the metallic implant
cannot occur, the implant remains
indefinitely "ankylosed" to the bone.

200. Resorption
• The bone resorption is almost universal, occurs
more frequently in posterior teeth, is usually
symmetrical
• It occurs in episodic spurts, is both of the horizontal
and vertical type (i.e., occurs from the gingival and
tooth side, respectively)
• It is intimately related to bacterial plaque and
pocket formation.
• Endotoxins produced by the gram negative bacteria
of the plaque lead to an increase in cAMP, which
increases the osteoclastic activity.

201. • Isolated areas in which the root is denuded of bone
and the root surface is covered only by periosteum
and overlying gingiva are termed fenestrations.
• In these instances the marginal bone is intact.
• When the denuded areas extend through the
marginal bone, the defect is called a dehiscence
Fenestrations and Dehiscences

202. Fate of PDL of primary
tooth
• In case of the periodontal
ligament it has been
demonstrated that apoptotic
cell death is involved.
• This form of cell death involves
shrinkage of the cells so that
they can be phagocytosed by
neighboring cells.
• Apoptotic cell death is a
normal feature of
embryogenesis and is
programed so that cells die at
specific times to permit
orderly development.

203. Biologic width
• The natural seal that develops around both,
protecting the alveolar bone from infection and
disease, is known as the biologic width.
• The biological width is defined as the dimension of
the soft tissue, which is attached to the portion of
the tooth coronal to the crest of the alveolar bone.
• “Biologic Width” term is coined by D.Walter Cohen .

204. Biologic width
(a) Histological sulcus
(0.69 mm)
(b) Epithelial
attachment
(0.97mm)
(c) Connective tissue
attachment
(1.07 mm)
(d) Biologic width (b+c)

205. Conclusion
• The normal periodontium is a unique and complex
dynamic structure providing support necessary to
maintain teeth in function
• Proper functioning of the periodontium is achieved
only through structural integrity and interaction
between the various tissues which are its
components.
• Certain features of gingiva and periodontium
exclusively seen in children may be normal findings
and unrelated to pathology.

206. Previously Asked
questionsSAQs
• Enumerate various gingival and periodontal diseases
in children and discuss clinical features and
management of ANUG. (2003)
• Prevalence of periodontal diseases in India.(2004)
• Scorbutic gingivitis (2006)
• Gingival diseases in children and its management.
(2008)

207. References
1. Orban’s Oral histology And Embryology, 13th
edition
2. Carranza’s Clinical Periodontology, 10th edition
3. Ten Cate’s Oral Histology, 8th edition
4. Oral Anatomy, Histology and Embryology, 4th
edition : Berkovitz B., Holland G., Moxham B.
5. Oral Development And Histology, 3rd edition;
James Avery
6. Shafer’ Textbook of Oral Pathology, 5th edition