The Gingiva

Embryology, Anatomy, Histology & Biochemistry

Dr. Khansa Ababneh

Periodontium Tissues which

surround & support the teeth.

Periodontium• Gingiva

• Periodontal ligament

• Alveolar bone

• Cementum

Tooth Development & Eruption

Periodontal tissues develop during tooth development

Development of the periodontium role of epithelial-mesenchymal interactions

Oral epithelium

Gingival epithelium

Ectomesenchyme (dental follicle)

PDLAlveolar bone

CementumGingival CT

Oral mucosa Masticatory

mucosa

Lining mucosa

Specialised mucosa

GINGIVA Part of masticatory

mucosa

Fibrous mucosa surrounding necks of teeth

covers the coronal portion of the alveolar process

GINGIVA

3 main parts:

1. Free gingiva

2. Attached gingiva

3. Interdental gingiva

Free gingivaFree gingiva From gingival margin

to the free gingival groove (FGG) at the level of the CEJ.

Can be separated form the tooth by a probe

Depth of gingival sulcus (crevice) : 0-3 mm.

Attached gingivaAttached gingivaExtends from the FGG to the mucogingival junction (MGJ)

Attached gingiva

On the palate, the whole mucosa is keratinised and there is No MGJ

Attached gingiva

Firmly attached to underlying bone to:

withstand masticatory forces

withstand forces of tooth brushing

prevent movement of marginal gingiva

Width varies in different parts of the mouth;

between right & left sides

between different people

with age (increases)

For example

Maxilla, buccally:widest around incisors, narrowest around

premolars

Mandible, linguallynarrowest around incisors, widest around molars.

Is the width of the attached gingiva important?

Which is more important; width or thickness?

Keratinised Vs Attached

Attached gingiva Keratinised gingiva

FG + AG

KG

Interdental gingiva Also: interdental

papilla.

Shape determined by:

Contact relationship between teeth

width of proximal surfaces

shape of the CEJ.

Anterior : Pyramidal Molars : Flattened in a

buccolingual direction. Between buccal & lingual

papillae

COL

Clinical Features of normal (healthy) gingiva

Colour: pink (physiologic/racial pigmentation)

Contour: scalloped outline Margins: thin, knife-edge. Surface texture: stippled Consistency: resilient Pointed interdental

papillae Probing depth: 0-3 mm. No bleeding on probing

(BOP).

HISTOLOGYHISTOLOGY The gingiva consists of 2 main types of

tissue:

1. Epithelium2. Connective tissue

• Epithelium is attached to the underlying connective tissue by a basement membrane.

EpitheliumEpithelium Stratified squamous epithelium (parakeratinised) Function:

Protection of underlying structures while permitting

selective interchange with the oral environment

Active production of cytokines, adhesion molecules,

growth factors and enzymes

Examples: β-defensins, IL-1 β, IL-8, EGF

StructureStructure Main cell type :

keratinocyte

4 layers of cells:1. stratum basale

(basal cell layer)

2. stratum spinosum (spinous cell layer)

3. stratum granulosum (granular cell layer)

4. stratum corneum (corneal or horny cell layer)

• The oral mucosa is mostly

parakeratinised: stratum corneum

retains pyknotic nuclei

• Difference between ortho- & para-

keratinisation

• Cytokeratin (K1-K19)

• Other proteins: keratolinin,

involucrin & filaggrin.

Other cell types within the gingival epithelium

Langerhans cells: modified monocytes

found in the suprabasal layer, playing a

role in immunity

Merkel cells: in deeper layer of

epitheium, contain nerve endings

Melanocytes: in basal and spinous cell

layer, contain melanin

Types of Gingival Epithelium

Oral epithelium

Sulcular epithelium

Junctional

epithelium

Oral epitheliumFaces the oral cavity, is parakeratinised, shows rete pegs and connective tissue papillae (responsible for the stippled texture). Turnover rate 10-12 days.

Sulcular epithelium Faces the tooth without contacting it. Thin non-keratinised stratified squamous epithelium (no granulosum and corneum layers), extends from the coronal end of the junctional epithelium to the crest of the gingival margin. Acts as a semi-permeable membrane.

Junctional epithelium Provides contact between

gingiva & tooth.

Stratified squamous non-keratinised epithelium.

3-4 cells thick in early life, increasing to 10-20 later.

Basal and suprabasal layers.

Length = 0.25-1.35 mm. No rete pegs.

Junctional Epithelium Derived from the

reduced enamel epithelium

Attachment to tooth: inner basal lamina

Attachment to gingival connective tissue: outer basal lamina

Lamina densa & lamina lucida

Large cells; wide intercellular spaces

ECM of Epithelium

Not abundant in gingival epithelium

PG: CD44, HA, syndecan, decorin

Glycoproteins: integrin family, e.g.: α2β1, and ICAM-1 (in Jep & Oep)

Differences between gingival epithelia Cell size/tissue volume in JE is > in OE

Intercellular spaces in JE are > in OE

No of desmosomes in JE is < in OE

Difference in cytokeratin expression & cell surface markers

JE originates from REE; OSE & OE originate from oral mucosa

Renewal of gingival

epithelium Cell sheddingCell division

The Dentogingival junction

Enamel + cementum (CEJ) +

junctional epithelium + gingival

fibres + adhesion proteins.

Dentogingival epithelium

Gingival Crevicular fluid (GCF)

In gingival sulcus

Cleaning & antimicrobial effects

Increases adhesion of gingiva to

tooth.

Connective Tissue

1. Cells: fibroblasts, mast cells, macrophages,

neutrophils, lymphocytes, plasma cells.

2. Collagen fibres3. Extracellular matrix (ECM)4. Nerves5. Blood vessels6. Lymphatics

Fibres Collagen, elastin,

reticulin & oxytalan

fibres.

Provide structure,

framework, increase

elasticity and

resiliency of gingiva.

Fibres Arranged in groups : :

Transseptal

Circular

Dentogingival

Dentoperiosteal

ECM Medium in which all other

components are embedded.

Consists of: water, proteins, glycoproteins, proteoglycans & growth factors:

Collagen type I , III, V & VI Proteoglycans: decorin, biglycan,

versican Integrins Fibronectin