Periodontology or Periodontics (from Greek περί peri "around"; and ὀδούς odous "tooth", genitive ὀδόντος odontos) is the specialty of dentistry that studies supporting structures of teeth, diseases, and conditions that affect them.

The supporting tissues are known as the periodontium, which includes the gingiva (gums), alveolar bone, cementum, and the periodontal ligament.

The Tissues of the Periodontium

Periodontium

It is the functional unit of tissue It is the functional unit of tissue supporting the teethsupporting the teeth

GingivaGingiva CementumCementum Alveolar processAlveolar process Periodontal ligamentPeriodontal ligament Junctional epitheliumJunctional epithelium

Types of Gingival Epithelium

Oral Mucous Membrane (Lining Mucosa)

Masticatory Mucosa Specialized Mucosa

NORMAL CLINICAL FEATURES

The gingiva is divided anatomically into marginal, attached, and interdental areas

Marginal Gingiva (Unattached Gingiva)

The terminal edge or border of the gingiva surrounding the teeth in a collar-like fashion

Marginal Gingiva (Unattached Gingiva)

The terminal edge or border of the gingiva surrounding the teeth in a collar-like fashion

The Attached Gingiva Is continuous with the marginal

gingiva It’s firm, resilient, and tightly

bound to the underlying periosteum of alveolar bone

The Interdental Gingiva

The interdental gingiva occupies the gingival embrasure

It is the interdental space beneath the area of the tooth contact

The interdental gingiva can be pyramidal or have a “col”

The Interdental Gingiva

Normal Microscopic Features

The gingiva consists of a central core of connective tissue covered by stratified squamous epithelium

Gingival Epithelium Three areas of epithelium exists in the

gingiva

Oral outer epithelium Sulcular epithelium Junctional epithelium

Layers of the Oral Epithelium

Stratum Corneum (Cornified Layer)

Stratum Granulosum (Granular Layer)

Stratum Spinosum (Prickle-cell Layer)

Stratum Basale (Basal Layer)

Layers of the Oral Epithelium Stratum Corneum (Cornified Layer) - it consists of very flat cells that have lost their nuclei and

cytoplasmic organelles

Stratum Granulosum (Granular Layer)

- characterized by the presence of keratohyalin granules Stratum Spinosum (Prickle-cell Layer)

- major epithelial layer, is composed of large cells with well developed desmosomes

Stratum Basale (Basal Layer)

- consists of relatively small cuboidal or polyhedral cells in contact with basal lamina, and in turn attached to connective tissue surface

Gingival EpitheliumGingival Epithelium

Three areas of epithelium exists in Three areas of epithelium exists in the gingivathe gingiva Outer or Oral EpitheliumOuter or Oral Epithelium Sulcular EpitheliumSulcular Epithelium Junctional EpitheliumJunctional Epithelium

The principal cell type of the oral The principal cell type of the oral and gingival epithelium, as well and gingival epithelium, as well as of other stratified squamous as of other stratified squamous epithelia , is epithelia , is keratinocyteskeratinocytes

Other cells found in epithelium Other cells found in epithelium are clear cells or are clear cells or nonkeratinocyes namely; nonkeratinocyes namely; Langerhans cells, the Merkel Langerhans cells, the Merkel cells, and melenocytescells, and melenocytes

Keratinocytes receives its Keratinocytes receives its name because it can name because it can synthesizesynthesize keratinkeratin

The process of keratinization involves a sequence of biological and morphological events that occur from the basal layer towards the surface

The process involves progressive flattening of the cells, with an increasing prevalence of tonofilaments and intercellular junctions as well as disappearance of the nucleus and production of keratohyaline granules

Keratinocytes constitute about Keratinocytes constitute about 90% or more of gingival 90% or more of gingival epitheliumepithelium

MelanocytesMelanocytes are dendritic cells are dendritic cells located in the basal and spinous located in the basal and spinous layers of the gingival epitheliumlayers of the gingival epithelium

They synthesize melanin in They synthesize melanin in organelles called organelles called premelanosomes or premelanosomes or melanosomesmelanosomes

They contain elongated granules and They contain elongated granules and considered to be macrophages with considered to be macrophages with possible antigenic propertiespossible antigenic properties

Langerhans cellsLangerhans cells are dendritic cells are dendritic cells located among keratinocytes at all located among keratinocytes at all suprabasal levelssuprabasal levels

Merkel cellsMerkel cells are located in the deeper are located in the deeper layers of epithelium and are the layers of epithelium and are the terminals of nerve fibers, connected to terminals of nerve fibers, connected to adjacent cells by desmosomes and adjacent cells by desmosomes and identified as tactile perceptorsidentified as tactile perceptors

Oral or Outer Epithelium

The oral and outer epithelium The oral and outer epithelium covers the crest of the outer surface covers the crest of the outer surface of the marginal gingiva and the of the marginal gingiva and the surface of the attached gingivasurface of the attached gingiva

Three Types of Surface Differentiation can occur in Gingival Tissue

1.1. Keratinization - in which the surface Keratinization - in which the surface cells form scales of keratin and lose cells form scales of keratin and lose their nucleitheir nuclei

2.2. Parakeratinization – in which the cells of Parakeratinization – in which the cells of the superficial layers retain their nuclei, the superficial layers retain their nuclei, albeit pyknotic, but show some signs of albeit pyknotic, but show some signs of being keratinizedbeing keratinized

3.3. Nonkeratinization – cells at the surface Nonkeratinization – cells at the surface layers are nucleated and no signs of layers are nucleated and no signs of keratinization are presentkeratinization are present

Degree of keratinization of oral mucosa varies in different areas in the

following order: palate (most keratinized)palate (most keratinized) gingivagingiva tonguetongue cheek (least keratinized)cheek (least keratinized)

Sulcular Epithelium Sulcular epithelium lines the Sulcular epithelium lines the

gingival sulcusgingival sulcus Nonkeratinized and usually shows Nonkeratinized and usually shows

numerous cells with hydropic numerous cells with hydropic degenerationdegeneration

Has the potential to keratinizeHas the potential to keratinize

Junctional Epithelium JE consists of a collar-like JE consists of a collar-like

band of stratified band of stratified squamous nonkeratinizing squamous nonkeratinizing epitheliumepithelium

Its thickness ranges from Its thickness ranges from 0.25 – 1.35mm0.25 – 1.35mm

The attachment of the JE The attachment of the JE to the tooth is reinforced to the tooth is reinforced by the gingival fibers, by the gingival fibers, which brace the marginal which brace the marginal gingiva against the tooth gingiva against the tooth surfacesurface

Stages of Passive Eruption Stage 1. The dentoepithelial junction

(DEJ) is located on enamel Stage 2. The DEJ is located on enamel as

well as cementum Stage 3. The DEJ is located entirely on

cementum, extending coronally to the cementoenamel junction

Stage 4. The DEJ is on cementum, and the root surface is exposed as a result of further migration of the DEJ on the cementum

Types of Gingival Fibers

A. DentogingivalA. Dentogingival B. DentoperiostealB. Dentoperiosteal C. AlveologingivalC. Alveologingival D. CircumferentialD. Circumferential E. SemicircularE. Semicircular F. TransgingivalF. Transgingival G. IntergingivalG. Intergingival H. TransseptalH. Transseptal

Vascular Supply The major arterial The major arterial

supply to the supply to the maxillary gingiva maxillary gingiva includes the includes the posterosuperior posterosuperior alveolar, the alveolar, the infraorbital, the infraorbital, the greater palatine, and greater palatine, and the sphenopalatine the sphenopalatine arteriesarteries

The mandibular The mandibular gingiva is supplied gingiva is supplied by branches of the by branches of the inferior alveolar inferior alveolar artery, including the artery, including the mental, the mental, the sublingual, and the sublingual, and the buccal arteriesbuccal arteries

Nerve Supply The maxillaryThe maxillary

gingiva is supplied gingiva is supplied by terminal by terminal branches of the branches of the posterior, middle, posterior, middle, and anterosuperior and anterosuperior alveolar nervesalveolar nerves

The mandibular The mandibular gingiva is supplied gingiva is supplied by the buccal and by the buccal and mental nerves on mental nerves on the vertibular side the vertibular side and the sublingual and the sublingual nerve on the lingualnerve on the lingual

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