Oral mucosa and periodontium

What are the 4 main functions of oral mucosa?

• Protection

• Sensation

• Secretion

• Mastication, speech and swallowing

Type of epithelium in the oral cavity

Stratified squamous epithelium to resist abrasion

Types of oral epithelium

Masticatory

Lining

Specialised

What type of oral epithelium is found on the hard palate, gingivae, dorsal surface of tongue

masticatory oral epithelium

What type of oral epithelium is found on the labial mucosa, buccal mucosa, alveolar mucosa, ventral tongue, floor of mouth, soft palate

lining oral epithelium

What type of oral epithelium is found on the gustatory mucosa of the tongue, vermillion zone/border between skin and oral mucosa

specialised oral epithelium (papillae)

Masticatory vs lining oral epithelium

Masticatory is keratinised to withstand forces generated during mastication

Lining is non-keratinised as it’s not subject to such high forces the the structures are elastic tissues which move out of the way

Label the 4 structures below the epithelium

1. Stratified squamous epithelium

2. Lamina propria (connective tissue)

3. Submucosa

4. Periosteum (only if over bone)

5. Bone/muscle

When is periosteum present

if over bone

What is found in the submucosa

fat deposits, glands, blood vessels

Name the 4 layers of keratinised oral epithelium from most to least matured

1. Keratinised cell layer – stratum corneum

2. Granular cell layer – stratum granulosum

3. Prickle cell layer – stratum spinosum

4. Basal cell layer – stratum basale

Name the 4 layers of non-keratinised epithelium

1. Superficial cell layer – stratum superficiale

2. Intermediate cell layer – stratum intermedium

3. Prickle cell layer – stratum spinosum

4. Basal cell layer – stratum basale

orthokeratinised vs parakeratinised

Orthokeratinised - no nuclei in keratinised layer

Parakeratinised - nuclei retained within keratinocytes

Function of basement membrane

• Connection between epithelium and lamina propria

• Site of metabolic exchange

• Controls biological behaviour of epithelial cells

What are rete ridges of the epithelium

Extensions of the epithelial layer into the dermal layer

What are papilla of the lamina propia

Protrusions of the dermal connective tissue into the epithelial layer

What are the layers of lamina propria

1. Papillary layer between epithelial rete ridges – thin, loose collagen fibres

2. Deeper reticular layer – thick, parallel bundles collagen fibres

Function of lamina propia

Provides mechanical support and nutrition for epithelium

What is found in submucosa

* Contains minor salivary glands, fat cells, blood vessels, nerves

Label A - F

A - Alveolar mucosa

C - Mucogingival junction

D - Attached gingivae

E - Free gingiva

F - Interdental papilla

Texture of free vs attached gingiva

Free - smooth

Attached - textured

Keratinisation of gingiva vs alveolar mucosa

Gingiva - keratinised

Alveolar - non-keratinised

Type of mucosa on the attached gingiva

masticatory mucosa

How is attached gingiva bound to bone

directly via mucoperiosteum

Where is interdental papilla and col found?

Triangles of the gums between teeth

how large is a healthy crevicular epithelium

0-2mm

Where is crevicular epithelium found

Unattached region between pre-gingiva and tooth (green line)

Where is junction epithelium found?

When the gingiva is connected to enamel

Why do the dark triangles appear in periodontal disease?

Interdental papilla lost

Crevicular vs junction epithelium

• Crevicular has more folding at interface with underlying tissue

• Crevicular has different site of keratin profile

Dentogingival junction

• Region where oral mucosa meets tooth surface

• Principal seal between oral cavity and underlying periodontal tissues

• Junction epithelium forms an epithelial collar around tooth from the cementoenamel junction to the base of the gingival sulcus

Thickness of crevicular vs junction epithelium

crevicular - 30 cells thick

junction - 1 cell thick

Attached gingiva

Free gingiva

Crevicular epithelium

Gingival sulcus

Gingival margin

Enamel space

Junction epithelium

Alveolar bone

Tooth (dentine)