002.anatomy and development of structures of PDL

Dr. Jaffar Raza Syed Page 1

Anatomy And Development Of

The Structures Of Periodontium

periodontium arises from the Greek word peri meaning around and

odont meaning tooth, thus it can be simply defined as the “tissues

investing and supporting the teeth”

The periodontium is composed of the following tissues namely

alveolar bone,

root cementum,

periodontal ligament (supporting tissues) and

gingiva (investing tissue).


various diseases of the periodontium are collectively

termed as periodontal diseases.

Their treatment is referred to as periodontal therapy.

The clinical science that deals with the periodontium in health

and disease is called periodontology.

The branch of dentistry concerned with prevention and treatment

of periodontal disease is termed periodontics or periodontia.

Dr. Jaffar Raza Syed

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The oral mucosa consists of three zones:

1. Masticatory mucosa: It includes the gingiva and the

covering of the hard palate.

2. Specialized mucosa: It covers the dorsum of the tongue.

3. Lining mucosa: It is the oral mucous membrane that lines

remainder of the oral cavity


The gingiva is divided anatomically

into

Free or marginal,

attached and

interdental gingiva.

The border or groove between marginal and attached gingiva is

called as a free gingival groove

The junction between the attached gingiva and alveolar mucosa is

called as mucogingival line or junction

The gingiva is divided anatomically


gingival groove.


mucogingival line or junction

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DEVELOPMENT OF PERIODONTIUM

Development of cementum

and roots of the teeth starts

once the formation of enamel

is completed.

The outer and inner epithelia

together form the epithelial

root sheath of Hertwig


Once the crown formation is complete the cells of the inner enamel

epithelium loose their ability to form enamel and is called reduced

enamel epithelium

DEVELOPMENT OF CEMENTUM

Cementoblasts: These cells are responsible for the deposition of

the organic matrix of cementum, which consists of proteoglycan

ground substance, intrinsic collagen fibers and is followed by

subsequent mineralization of the organic matrix


The periodontal ligament forms from the dental follicle soon after

root formation begins.

fibers from the follicle are incorporated in the cementum and they

are called as Sharpey’s fibers

Alveolar bone forms around the periodontal ligament With

continuous bone deposition the periodontal ligament space

gradually becomes narrower. The alveolar process develops during

the eruption of the teeth and cells responsible for bone formation

are osteoblasts


Development of Junctional Epithelium

When the enamel formation is complete The inner enamel

epithelium after laying down enamel reduces to a few layers of

flat cuboidal cells, which is then called as reduced enamel

epithelium.

It covers the entire enamel surface extending till the

cementoenamel junction. During eruption, the tip of the tooth

approaches the oral mucosa leading to fusion of the reduced

enamel epithelium with the oral epithelium.


As the crown emerges into

the oral cavity the former

ameloblasts that are in contact

with the enamel get trans

formed into junctional epithelium.

Coronally, the JE is continuous

with the oral epithelium.

As the tooth erupts, the reduced enamel epithelium grows

shorter gradually. A shallow groove, the gingival sulcus may

develop between the gingiva and the tooth surface.

As the crown emerges into

the oral cavity the former

ameloblasts that are in contact

get trans-

junctional epithelium.

is continuous

with the oral epithelium.



e gingiva and the tooth surface.

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When the junctional epithelium forms from the ameloblasts it is

called primary epithelial attachment.

Junctional epithelium that forms after surgical therapy takes its

origin from the basal cells of oral epithelium instead of ameloblast

is called secondary epithelial attachment

Health & Medicine

002.anatomy and development of structures of PDL