biology of the um

8/3/2019 Biology of the um

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BIOLOGY OF THEPERIODONTIUM

Anatomy

Histology


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Oral Mucosa

Masticatory mucosa

Lining mucosa

Specialized mucosa


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Gingiva

Marginal Gingiva -

Interdental Gingiva

Attached Gingiva -


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Cross-section of theperiodontium


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Normal clinical condition of the

gingiva


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Normal features of the gingiva


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Gingival Sulcus

A crevice foundaround the tooth

Space has a depth

of 1 to 2mm

Foci of initial site ofperiodontal disease

activity Receives sulcular

fluid which isantibacterial


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Gingival fluid

Fluid that seeps into from the gingivalconnective tissue through a thin sulcularwall

Antimicrobial properties

Periodontal disease activity


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Attached Gingiva

Firm

Resilient


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Attached gingiva


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Variations in the width of theattached gingiva


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Interdental Papillae

Confined in the interproximal embrasure

Parts are col, lingual and facial peaks

Shape is determined by the contactarea, width of approximal toothsurfaces, and course of the CEJ


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Gingival Col / contact area


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Epithelium

Outer covering ofthe gingiva

Made up of stratified

squamousepithelium

Divided into

oral epitheliumsulcular epithelium

junctional epithelium


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Types of Epithelial surface

Keratinization

Parakeratinization

Non keratinization


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Keratinized epithelium


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Parakeratinized epithelium


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Nonkeratinized Epithelium


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Principal cells of theepithelium

Keratinocyte

Melanocyte

Langerhans cellsMerkel cells


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Layers of the epithelium

Stratum corneum

Stratum granulosum

Stratum spinosum

Stratum basale


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Dentogingival Junction

Sulcular epithelium

Junctionalepithelium


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Development of thedentogingival junction

Ameloblast is reduced in height

Basal lamina and OE Epithelium

RE Epithelium surrounds the crownTooth erupts in to OC

REE and OE forms JE

Hemidesmosome == Epithelialattachment


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Development of the sulcus


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Junctional epithelium


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Supra-alveolar Connectivetissue

Cell fibroblast, mesenchymal cells,mast cells , macrophages

Connective tissue fibers collagen,elastic fibers


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Gingival Fibers

Gingivo-dental fibers

Dento-periostealfibers

Circular fibers

Inter-papillary groupof fibers

Semicircular fibers


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Gingival Fibers

Intergingival fibers

Transgingival fibers

Transseptal fibers


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Gingival fibers


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Lamina Propria

Dense connective tissue

Interspersed with theinterfibrillary ground

substance

Bl d l f th


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Blood supply of thePeriodontium

Supra-periostealarterioles

Vessels of the

periodontal ligament Arterioles from the

alveolar crest

L h ti f th


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Lymphatics of thePeriodontium

Connective tissue papillae collectingnetwork external to the periosteum ofthe alveolar crest regional lymphnodes (sub-maxillary group)

Lymphatics beneath the epithelialattachment extend into the periodontal

ligament and accompany the bloodvessel


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Gingival nerve supply

Meshwork of terminal argyrophilic fibers

Meissner-type of tactile corpuscles

Krause-type end bulbEncapsulated spindle


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Criteria of a healthy gingiva

Color

Surface texture

Form

Consistency

Position of thegingiva


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Dentogingival junction

Active eruption ofthe tooth

Passive eruption -

Apical shift of JE Gingival recession

clinical result

D f M h i f th


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Defense Mechanism of theGingiva

Protection-epithelium

Mechanical saliva and epithelial cells

Cellular PMN Inflammationdentoepithelial junction


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Periodontium

Gingiva

Periodontal ligament

CementumAlveolar bone


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Functions of the Periodontium

Supportive

Investive


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Dento alveolar Unit

Cementum

Bone

Periodontal Ligament


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Cementum

Acellular cementum

Cellular cementum


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Acellular Cementum

Structureless substance formed

by cementoblast which is notembedded in the matrix


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Cellular cementum

Cells caught within the matrix;

thickest at the apical area

Classification of Cementum


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Classification of CementumSchroeder

Acellular afibrillar cementum AAC

Acellular extrinsic fiber cementumAEFC

Cellular mixed stratified cementumCMSC

Cellular intrinsic fiber cementum CIFC Intermediate cementum


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Type of cementum

1. Acellular afibrillarcementum

Acellular extrinsic-

fiber cementum Cellular intrinsic-

fiber cementum

Cellular mixed fibercementum

Histological Elements of


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Histological Elements ofCementum

Cementum matrix

Sharpeys fibers

CementocytesLacuna and canaliculi


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Cemento-dentinal Junction

Referred to intermediate cementum

Permanent teethsmooth

Temporary teeth - wavy

Spatial relationship of


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Spatial relationship ofcementum and enamel

60%-65% -cementum overlapscervical end of the

enamel 30% - cervical end

of cementum meetsthe cervical end of

enamel

5%-10% - failure forE and C to meet

Clinical Considerations for


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Clinical Considerations forcementum

Coronal cementum

Cementicles

Hypercementosis


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Periodontal Ligament

Fibrous attachmentof the tooth insertinginto cementum and

alveolar bone.


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Principal fibers

Collagenouscontent

Arranged in fibersbundles

Seen in a wavyform ( lightmicroscope)

Made up ofamino-acids

Tropocollagenmolecule in thefibroblast ;collagen type I

Tranversestriation


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Structures of the PDL

Interstial tissue

Oxytalan fibers

Eluanin Indifferent fiber

plexus

Principal fibersCementicles

Connective tissuecells

Epithelial rest ofMalassez

Defense cells


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Ground substance

Fills up the space between cells andfiber bundles

Components are:

> glycosaminoglycans

> glycoproteins

Principal Fibers of the


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Principal Fibers of thePeriodontal ligament

Alveolar crestalgroup

Horizontal group

Oblique group

Apical group

Inter-radicular group


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Functions of the PDL

Formative

Supportive

Sensory

Nutrition

Physical


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Physical function

Resistance to theimpact of occlusalforces

Transmission ofocclusal forces tobone

Occlusal functionand structure of thePDL


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Alveolar Bone

Extension of mandible and maxilla

which forms the sockets wherethe roots of the teeth are fitted


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Maxilla / Mandibular bone


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Type of bone

Compact bone

Spongy bone

Relative proportions of


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Relative proportions of

cancellous and compact bone


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Alveolar process

One mm. away from the cej

Position of the tooth determines thelocation of the alveolar socket

Structural character depends on thefunctional demands


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ALVEOLAR PROCESS

External plate ofcortical bone

Alveolar bone

proper Cancellous

trabeculae

Nomenclature according to


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Nomenclature according tolocation

Radicular bone

Interproximal bone

Interradicular bone


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Interdental septum

Cancelloussupporting bone

Enclosed with

compact bone


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Basal bone

Apical area ofalveolus


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Biologic width

1 mm sulcular area

1 mm junctionalepithelium

1mm connectivetissue

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