Clinical anatomy and histology of periodontiumby mohamed assaadwy

Clinicalcorrelationof normalperiodontium
Dr Mohamed Assadawy
Lecturer of Oral medicine , Periodontology ,Oral diagnosis and Oral radiology
10/12/2018 DRMOHAMEDASSADAWY

Lecture outlines
Definition of normal periodontium
Macroscopic features (clinical anatomy)
Microscopic features (histologic features)
Correlation of Clinical and Microscopic Features

Definition:
The periodontium, literally “around the tooth,” comprises the tissues that invest and support
the teeth in the maxilla and mandible.

Oral Mucosa
The oral mucosa consists of the following three zones:
1. The gingiva and the covering of the hard palate, termed the
masticatory mucosa (The gingiva is the part of the oral mucosa that
covers the alveolar processes of the jaws and surrounds the necks
of the teeth.)
2. The dorsum of the tongue, covered by specialized mucosa
3. The oral mucous membrane lining the remainder of the oral
cavity(lining Mucosa)

Diagram showing representative cells from the various layers of stratified squamous epithelium as seen by
electron microscopy

Cellular layers of epithelium10/12/2018 DRMOHAMEDASSADAWY

Macroscopic features
The gingiva is divided anatomically into marginal, attached, and interdental
Marginal Gingiva.
The marginal or unattached gingiva is the terminal edge or border of the gingiva that surrounds the teeth in collar like
fashion .
Attached Gingiva.
The attached gingiva is continuous with the marginal gingiva. It is firm, resilient, and tightly bound to the underlying
periosteum of alveolar bone. The facial aspect of the attached gingiva extends to the relatively loose and movable
alveolar mucosa; it is demarcated by the mucogingival junction .
Interdental Gingiva.
The interdental gingiva occupies the gingival embrasure, which is the interproximal space beneath the area of tooth
contact. The interdental gingiva can be pyramidal, or it can have a “col” shape. In the former, the tip of one papilla is
located immediately beneath the contact point; the latter presents a valleylike depression that connects a facial and
lingual papilla and that conforms to the shape of the interproximal contact.

•Gingival sulcus : A shallow groove between the marginal gingival and the
tooth surface, bound by sulcular epithelium laterally and juncitonal epithelium apically.
•Gingival groove : Indentation along the oral or vestibular surface of the marginal
gingival which parallels the gingival margin. It is located at about the same level as the
apical border of the junctional epithelium. Note : its level does not correspond to that of
the bottom of the sulcus.
•Mucogingival junction : Demarcation line between masticatory mucosa of the
gingival and the lining alveolar mucosa.

Microscopic Features of gingiva
Overlying stratified squamous epithelium
and the underlying central
core of connective tissue.

MICROSCOPIC FEATURES
GINGIVAL EPITHELIUM (divided into 3 types)
1.Oral epithelium (OE): Stratified, squamous keratinizing epithelium which lines the oral (as contrasted to the
dental) surface of the gingiva. It extends from the mucogingival junction to the gingival margin (except for the
palatal surface where it blends with palatal epithelium).
2.Sulcular epithelium (SE) : Stratified, squamous epithelium, generally non-keratinized, which is continuous with
the oral epithelium, lines the peripheral surface of the sulcus, and overlaps the coronal border of the junctional
epithelium.
3.Junctional epithelium (JE) : Stratified non-keratinizing epithelium, in the shape of a collar with a cross-section
resembling a thin wedge, attached by one broad surface to the tooth and by the other broad surface to the gingival
connective tissue. New cells originate from apical cells and cells in contact with connective tissue. The
desquamative surface is a t the coronal end which forms the bottom of the sulcus.

Unique features
1. The cells are largely undifferentiated and lack tonofibrils.
2. Intercellular junctions are less frequent that in OE or SE (junction density in
JE is approximately 25% that of OE or SE).
3. The epithelium has 2 basal laminas, one which faces the tooth and one
which faces the connective tissue.
4. Epithelial attachments : refers to the basal lamina and hemidesmosomes that
connect the JE to the tooth surface.
5. The JE is more permeable than OE or SE to cells and fluids. It serves as the
preferential route for the passage of fluid and cells from the connective
tissue into the sulcus, and for bacterial products originating in the sulcus into
the connective tissue.
6. In the presence of inflammation, it is readily ruptured by mechanical forces.

CONNECTIVE TISSUE (lamina properia)
Gingival fibers : The majority are composed of collagen fibers, with minor contributions from
elastic fibers and oxytalan fibers (the fiber). Elastic and oxytalan fibers are generally confined to
perivascular regions, although oxytalan fibers may appear as thin fiber bundles within collagen-rich
region

Ground substance : Occupies the space between cells, fibers and neurovascular elements. Major components
are water, glycoproteins and proteoglycans. Allows diffusion of biological substances between various structural
elements.
Cells:
Fibroblasts: Synthesis and resorption
Macrophages : Participate in host defense and repair
Mast cells : Participate in early phase of inflammation
Undifferentiated cells : source of new cells
Leukocytes (neutrophils, lymphocytes, plasma cells, etc…) : Participate in host defense.
Osteoblasts, cementoblasts, osteoclasts, cementoclasts Vessels and nerves :
Blood supply : Capillary network subjacent to oral epithelium and junctional vessels originating from periosteal
surface of alveolar bone, marrow spaces of alveolar bone and periodontal ligament.
Lymphatics : drain principally to submaxillary lymph nodes
Nerves : Braches of the traigeminal nerve provide sensory and proprioceptive functions. Autonomic nerve
endings associated with vasculature.
Connective tissue-epithelial interatiions :
May have a significant effect on tissue differentiation

Clinical landmarks of the gingivae. Free gingiva is composed of epithelial tissue with an
attaching structure. Below this is the attached gingiva. The diagrams show (a) the front
picture of typical healthy gingiva (bar = 1 mm) (b) the cross section of gingiva penetrated by
tooth (c) the clinical front view.

directly attached to the tooth (DAT cells) and a basal lamina-like extracellular matrix,
termed the internal basal lamina, on the tooth surface [

Drawing of the junctional epithelium. D: dentin, E: enamel, C: cementum, CT: connective tissue, EBL: external basal
lamina, IBL: internal basal lamina, EC: epithelial cell of the junctional epithelium, De: desmosome, HD: hemidesmosome

Functions and Features of Gingival Epithelium
Functions
Mechanical, chemical,
water, and microbial barrier
Signaling functions
Architectural Integrity
Cell-cell attachments
Basal lamina
Keratin cytoskeleton
Major Cell Type
Keratinocyte
†Other Cell Types
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
„ Hemidesmosomes

Outer Epithelium
The oral or outer
epithelium covers the crest
and outer surface of the
marginal gingiva and the
surface of the attached
gingiva.
it is keratinized or
parakeratinized. The
prevalent surfaces however,
is parakeratinized.
Keratinization of the oral
mucosa: palate (most
keratinized), gingiva,
tongue, and cheek (least
keratinized)."
Sulcular Epithelium
†The sulcular epithelium lines
the gingival sulcus . It is a thin,
Nonkeratinized, stratified
squamous
epithelium without rete pegs
and extends from the coronal
limit of the junctional epithelium
to the crest of the gingival
margin .the sulcular epithelium
is e
act as a semipermeable
membrane through which
injurious bacterial products
pass into the gingiva and
through which tissue fluid from
the gingiva
seeps into the sulcus
Junctional Epithelium (JE)
Stratified squamous
nonkeratinizing epithelium.
3-4 layers thick in early life,
but with age to 10-20.
†The length of the JE ranges
from 0.25 to 1.35 mm
P MN are found routinely in
the JE
More permeable than Sulcular
epithelium

Gingival Fluid (Sulcular Fluid)
It can be represented as either a transudate or an exudate
It is potential use as a diagnostic or prognostic biomarker of the biologic state of the periodontium
in health and disease.
It is contains components of connective tissue, epithelium,
inflammatory cells, serum, and microbial flora inhabiting the gingival
margin or the sulcus (pocket).
In the healthy sulcus the amount of the gingival fluid is very small.
During inflammation, however, the gingival fluid flow increases
†The main route of the gingival fluid diffusion is through the basement membrane, through the relatively wide
intracellular spaces of the junctional epithelium, and then into the sulcus.
The functions are:
Cleanse material from the sulcus,
Contain plasma proteins that may improve adhesion of the epithelium to the tooth,
Possess antimicrobial properties,
Exert antibody activity to defend the gingival.

Gingival Connective Tissue
The major components of the gingival connective tissue are collagen fibers (about 60% by volume),
fibroblasts (5%), vessels, nerves, and matrix (about 35%).
It is known as the lamina propria and consists of two layers:
A papillary layer subjacent to the epithelium, which consists of papillary projections between
the epithelial rete pegs,
a reticular layer contiguous with the periosteum of the alveolar bone.
The ground substance fills the space between fibers and
cells, is amorphous, and has a high content of water

Lamina propria
The gingival connective tissue (lamina propria) consists of:
•Papillary layer
•Reticular layer
Papillary layer consist of fine loosely arranged fibers. Papillary projection can be found between
the rete pegs of the epithelial layer (epithelial extensions that project into the underlying
connective tissue).
Reticular layer consists of dense irregular connective tissue.
The connective tissue consists of cellular (mainly fibroblasts, mast cells, white blood cells), and
extracellular compartment (ground substance).
The main types of fibers found in the gingival are the type I, III and V collagen fibers. They
radiate in the cementum, the periosteum of the alveolar bone, and directly in the alveolar bone.
Their main functions are to connect the gingival to the tooth, to provide rigidity against
mastication.

they can be classified as:
A.Dentogingival fibers: running from the supraalveolar root cementum coronally (coronal), horizontally (horizontal) or
towards the apex (apical).
B.Alveologingival fibers: running almost vertically from the alveolar border to the interdental and vestibule-oral
gingiva.
C.Interpapillary fibers: connecting the interdental buccal and oral interdental papilla. They cross in the col area.
D.Transgingival fibers: fibers connecting the gingival fibers of the adjacent teeth.
E.Circular, semicircular fibers: supraalveolar position. Circular fibers are running in the marginal gingiva, they
encircle the teeth. Semicircular fibers are found on the buccal side of the teeth.
F.Dentoperiostal fibers: running between the root cementum and the periosteum of the alveolar bone.
G.Transseptal fibers: also called interdental fibers running above the interdental alveolar septum and connecting the
cementum of the adjacent teeth.
H.Periostogingival fibers: radiate from the buccal and lingual periosteum of the alveolus to the attached
gingiva/running on the buccal and lingual side everywhere in the attached gingiva connecting the periosteum and the
gingiva.
I.Intercircular fibers: connecting the intergingival fibers to the fibers running between the teeth.
J.Intergingival fibers: continuously running fibers converging towards the molar teeth

 Gingival Sulcus
It is the shallow crevice or space around the tooth
bounded by the surface of the tooth on one side and the
epithelium lining the free margin of the gingiva on the
other side.
 It is V shaped, and it permits the entrance of a
periodontal probe
The clinical determination of the depth of the gingival
sulcus is an important diagnostic parameter.
 The histologic depth of a sulcus does not need to be
exactly equal to the depth of penetration of the probe.
The so-called probing depth of a clinically normal
gingival sulcus in humans is less than 3 mm

Clinical considerations

CORRELATION OF CLINICALAND MICROSCOPIC FEATURES
Color
The color of the attached and marginal gingiva is generally described as "coral pink" and is produced by
The vascular supply,
The thickness and degree of keratinization of the
epithelium, and the presence of pigment-containing cells.
The alveolar mucosa is red, smooth, and shiny rather
than pink and stippled. The epithelium of the alveolar mucosa is thinner, is
nonkeratinized, and contains no rete pegs
The connective tissue of the alveolar mucosa is loosely
arranged, and the blood vessels are more numerous

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
Contour
The contour or shape of the gingiva varies considerably and
depends on the shape of the teeth and their alignment in the arch,
the location and size of the area of proximal contact,
the dimensions of the facial and lingual gingival embrasures.
the marginal gingiva envelops the teeth in collar like fashion
and follows a scalloped outline on the facial and lingual
surfaces.

Consistency
The gingiva is firm and resilient and, with the exception of the movable free margin, tightly bound to the
underlying bone.
T he 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.
The gingiva presents a textured surface similar to an orange peel and is referred to as
being stippled Stippling is best viewed by drying the gingiva.
The attached gingiva is stippled; the marginal gingiva is not.
The central portion of the interdental papillae is usually stippled, but the marginal borders are smooth. The
pattern and extent of stippling vary among individuals and different areas of the same mouth.
Stippling is less prominent on lingual than facial surfaces and may be absent in some persons.
It is absent in infancy, appears in some children at about 5 years of age, increases until adulthood,

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.
†During this eruption process,
The junctional epithelium, oral epithelium, and reduced
enamel epithelium undergo extensive alterations and
remodeling.
The distance between the apical end of the junctional
epithelium and the crest of the alveolus remains
constant throughout continuous tooth eruption (1.07 mm).

1-The base of the gingival sulcus (arrow) and the junctional epithelium (JE) are on the enamel.
2, The base of the gingival sulcus (arrow) is on the enamel, and part of the junctional epithelium is on the root.
3, The base of the gingival sulcus (arrow) is at the cementoenamel line, and the entire junctional epithelium is on the root.
4, The base of the gingival sulcus (arrow) and the junctional epithelium are on the root

Periodontal ligament
The periodontal ligament is the connective tissue
that surrounds the root and connects it with the bone.
It is continuous with the connective tissue of
the gingiva and communicates with the marrow spaces
through vascular channels in the bone.
†the average width is
about 0.2 mm

Functions of the Periodontal Ligament
 Physical Function
 Formative and Remodeling Function
 Nutritional and Sensory Functions

Physical Functions
 Provision of a soft tissue "casing" to protect the vessels and nerves from injury by mechanical
forces.
 Transmission of occlusal forces to the bone.
 Attachment of the teeth to the bone.
 Maintenance of the gingival tissues in their proper relationship to the teeth.
Resistance to the impact of occlusal forces (shock absorption)
Light forces are absorbed by intravascular fluid that is forced out of the blood vessels
Moderate forces are also absorbed by extravascular tissue fluid that is forced out of the
periodontal ligament space into the adjacent marrow spaces The heavier forces are taken
up by the principal fibers

Formative and Remodeling Function
Cells of the periodontal ligament participate in the
formation and resorption of cementum and bone
which occur:
in physiologic tooth movement;
in the accommodation of the periodontium to occlusal forces;
and in the repair of injuries.
The periodontal ligament is constantly undergoing
remodeling.
Old cells and fibers are broken down and replaced by new
ones, and mitotic activity can be observed in the fibroblasts
and endothelial cells.
Fibroblasts form the collagen fibers and may also develop into
osteoblasts and cementoblasts.

Nutritional and Sensory Functions
Supplies nutrients to the cementum, bone, and gingiva
by way of the blood vessels and provides lymphatic drainage.
Supplied with sensory nerve fibers capable of transmitting tactile,
pressure, and pain sensations by the trigeminal pathways.
Nerve bundles pass into the periodontal ligament from
the periapical area and through channels from
the alveolar bone that follow the
course of the blood vessels

Periodontal ligament composed of
 Cellular elements.
 Periodontal fiber groups.
 Ground substances.

The cells include osteoblasts and osteoclasts,
fibroblasts, epithelial cell rests of Malassez,
monocytes and macrophages, undifferentiated
mesenchymal cells, and cementoblasts and
odontoclasts. stem cell characteristics have been
isolated from the human periodontal ligament

The periodontal ligament are arranged in groups
according to location
 Transseptal
 Alveolar crest
 Horizontal
 Oblique
 Apical
 Interradicular

Ground substance
Filling The Space Between The Fibers & Cells.
 Glycosaminoglycans
Hyaluronic Acid
Proteoglycans
 Glycoproteins
Fibronectin
Laminin

Alveolar bone
The alveolar process is that bone of the jaws containing the sockets (alveoli) for the teeth. It
consists of outer cortical plates (buccal, lingual, and palatal) of compact bone, a central
spongiosa, and bone lining the alveolus (alveolar bone).

Alveolar process
1 Alveolar bone, or
Cribriform plate (histologic term)
Alveolar wall (anatomical term)
Lamina dura (Radiographic Term)
2 Trabecular bone
3 Compact bone

GROSS MORPHOLOGY
• Outer alveolar plate
• Inner alveolar plate
• Interdental septum
• Interradicular septum

Cells and intercellular matrix
Osteocyte, Osteoblasts, Osteoclasts
Bone consist of 65% hydoxyapatite Organic
matrix consists mainly (90%) of collagen type 1
with small amounts of osteocalcin, osteonectin,
bone morphogenetic protein, phosphoproteins,
and proteoglycans

Periosteum and Endosteum
All bone surfaces are covered by connective tissue.
Outer surface _periosteum . Internal _ endosteum.
The periosteum consists of an inner layer composed of cells
that have the potential to differentiate into osteoblasts
an outer layer that is rich in blood vessels and nerves
and is composed of collagen fibers and fibroblasts.
Bundles of periosteal collagen fibers penetrate the
bone, binding the periosteum to the bone the
endosteum is composed of a single layer of
osteoprogenitor cells and a small amount of
connective tissue

lnterdental Septum
 The interdental septum consists of cancellous bone and cortical plates.
if the interdental space is narrow, the septum may consist of only lamina dura
(between mandibular 2nd premolars and 1st molars consists of only lamina dura in
15% cases.
if roots are too close together, an irregular "window" can appear in the bone between
adjacent roots
 The mesiodistal angulation of the crest of the interdental septum usually parallels a
line drawn between the cementoenamel junctions of the approximating teeth.
 the distance between the crest of the alveolar bone and the CEJ in young adults
varies between 0.75 and 1.49 mm (average, 1.08 mm). This distance increases with
age to an average of 2.81 mm.

Contours
Normally conforms to the
prominence of the roots,
The height and thickness of the
facial and lingual
bony plates are affected by the
alignment of the
teeth, by the angulation of the
root to the bone, and
by occlusal forces.

Fenestrations and Dehiscences
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. Fenestration and dehiscence are
important,
because they may complicate the outcome of
periodontal surgery
F
D

Patterns of bone loss
- horizontal bone loss
- vertical defects
- osseous craters
- bulbous bone contours
- ledges
- reversed architecture
-furcation involvement

REGULATORS OF BONE FORMATION
• The overall integrity of bone is controlled by hormones, proteins secreted by
hematopoietic bone marrow cells and bone cells.
HORMONES
• Parathormone
• Vitamin D3
• Glucocorticoids
• Thyroid Hormone
• Growth Hormone
• Insulin
LOCAL REGULATORS
• Platelet derived growth factor
• Insulin growth factors
• Transforming growth factor-β
• Bone morphogenetic protein
• Fibroblast growth factor

BONE REMODELING
• The process by which overall shape and size of bones is established is
referred to as bone remodelling or turnover.
• It occurs in discrete, focal areas involving groups of cells called bone
remodelling or basic multicellular units.
The main functions of remodeling are- To prevent the accumulation of
damaged and fatigued bone by regenerating new bone. to allow bone to
respond to changes in mechanical forces.
To facilitate mineral homeostasis.

Cementum
Cementum is a collagen-based
mineralized tissue produced by
cementoblasts. Acellular cementum
covers the dentin of the coronal
portion of the root; cellular
cementum, containing cementocytes
located in lacunae, is present on the
apical portion of the root and in the
furcation areas of multirooted teeth.

• Acellular afibrillar cementum contains neither cells nor extrinsic or intrinsic collagen fibers,
except for a mineralized ground substance.
Acellular afibrillar cementum is a product of cementoblasts and found
as coronal cementum in humans, with a thickness of 1 to 15 µm.
• Acellular extrinsic fiber cementum is composed almost entirely of densely
packed bundles of Sharpey fibers and lacks cells.
Acellular extrinsic fiber cementum is a product of fibroblasts and
cementoblasts. It is found in the cervical third of roots in humans, but it may extend farther
apically. Its thickness is between 30 and 230 µm.

Normal variations in tooth morphology at the cementoenamel junction. (A) Space between the
enamel and the cementum with the dentin (D) exposed. (B) End-to-end relationship of enamel and
cementum. (C) Cementum overlapping the enamel

• Cellular mixed stratified cementum is composed
of extrinsic (Sharpey) and intrinsic fibers, and it may contain cells. Cellular mixed stratified
cementum is a co-product of fibroblasts and cementoblasts. In humans, it appears primarily in
the apical third of the roots and apices and in
furcation areas. Its thickness ranges from 100 to 1000 µm.
• Cellular intrinsic fiber cementum contains cells but no extrinsic collagen fibers. Cellular
intrinsic fiber cementum is formed by cementoblasts, and,
in humans, it fills the resorption lacunae.
• Intermediate cementum is a poorly defined zone near the
cementodentinal junction of certain teeth that appears to contain
cellular remnants of the Hertwig sheath embedded in a calcified
ground substance

Inorganic content of cementum (hydroxyapatite;
Ca10[Po4]6[OH]2) is 45% to 50%, which is less
than that of bone (65%), enamel (97%), or dentin
(70%). and no relationship has been established
between aging and the mineral content of
cementum

Composition of cementum

Function of root cementum
• The attachment of the principal fibers of PDL to root surface is mediated by
cells ( fibroblasts & cementoblasts) through organizing & orienting extra cellular
fibers into functional networks.
Cementum Hypertrophy
1- Cemental Hypertrophy: Increased cementum formation at apical third
(functional adjustment)
2- Cemental Hyperplasia: Defective condition resulting in increased cemental
formation.
Cementum hyperplasia • Occur on root surface of patients suffering from an
auutosomal-ressesive trait “Hypophosphatasia”. clinically presented in the form
of defective cementum (= loss of attachment)

CLINICAL CONSIDERATIONS
 Cementum is essential for normal anchorage of the tooth.
 Cementum also provides a protective function to the tooth itself, as it is less susceptible to resorption than
bone.
 Scaling and root planing, aimed at removing calculus and bacterial deposits ,formation of smear layer which
act as weak bond in new junction.
 New cementum formation is a key process during therapeutic procedures aimed at gaining new attachment
 Cemental deposition in the apical portion of the root compensates for occlusal attrition .
 Anomalies in cementogenesis may have significant implications in periodontal disease and in extraction.

Thank you and good luck

Clinical anatomy and histology of periodontiumby mohamed assaadwy

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