Gingiva-summer

  • November 2019
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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)

PDL Alveolar bone Cementum Gingival 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: •

Free gingiva



Attached gingiva

3.

Interdental gingiva

Free 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 gingiva

Extends 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, lingually narrowest 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).

HISTOLOGY The gingiva consists of 2 main types of tissue:



1. 2. •

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

Epithelium  

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

 Main cell type :

keratinocyte

 4 layers of cells: 1. stratum basale (basal cell layer) 2. stratum spinosum (spinous cell layer) –

stratum granulosum (granular cell layer)

4. stratum corneum (corneal or horny cell layer)

Structure



The oral mucosa is mostly parakeratinised: stratum corneum retains pyknotic nuclei



Difference between ortho- & parakeratinisation



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 epithelium Faces 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 nonkeratinised 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 semipermeable membrane.

Junctional epithelium 





 

Provides contact between gingiva & tooth. Stratified squamous nonkeratinised 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

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 division

Cell shedding

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 •

Cells: 

2. 3. 4. 5. 6.

fibroblasts, mast cells, macrophages, neutrophils, lymphocytes, plasma cells.

Collagen fibres Extracellular matrix (ECM) Nerves Blood vessels 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 