Gingiva

Question 1

Where is the narrowest and widest zone of gingiva?

Answer 1

Narrowest is mandibular canine and premolar region

Thickest is the lingual second molar region

Question 2

What are the 3 types of gingival epithelium?

Answer 2

Oral epithelium
Sulcular epithelium
Junctional epithelium

Question 3

Describe the histological characteristics of the oral epithelium

Answer 3

Stratified squamous keratinised epithelium
Consists of basal layer, spinous layer, granular layer, cornified layer
intercellular junctions (desmosomes) which hold the cells tightly together
Connected to underlying connective tissue by fingerlike projections. Rete ridges form the undersurface of the epithelium

Question 4

Describe the histological characteristics of sulcular epithelium

Answer 4

Stratified squamous non-keratinised or para-keratinised

Overall structure is similar to oral epithelium but surface layer is less keratinised

Question 5

Describe the histological characteristics of the junctional epithelium

Answer 5

Stratified non-keratinising epithelium
2 basal laminas. Internal basal lamina which faces the tooth. External basal lamina which faces the connective tissue.
Connectivity via DAT cells
Porous due to wide intercellular spaces

Question 6

How does the junctional epithelium differ from the oral and sulcular epithelium?

Answer 6

More permeable.
Intercellular spaces between the cells are wider.
Attached by two surfaces

Question 7

Described the histological characteristics of gingiva compared to alveolar mucosa

Answer 7

Gingiva: deep rete pegs, thick lamina propia, few elastic fibres, firmly attached

Alveolar mucosa: non-keratinised, unstippled, few short wide rete pegs, thin lamina propia, numerous elastic fibres, moveable

Question 8

In health how long is the junctional epithelium?

Answer 8

1-2mm

Question 9

What cells allow each side of the junctional epithelium to have connectivity?

Answer 9

Direct attached to the tooth cells (DAT cells)

Question 10

What lies between the enamel space and the junctional epithelium?

Answer 10

Dental cuticle and DAT cells

Question 11

What are the two theories for the origin of junctional epithelium?

Answer 11

Gradual replacement with oral epithelium cells - this study they cut away junctional epithelium and it grew back
Odontogenic derived epithelium - mouse study which suggested the JE was from reduced enamel epithelium

Question 12

What are 3 techniques to visualise keratinised gingival tissue?

Answer 12

Visual method
Functional method
Histochemical method with iodine

Question 13

What percentage of the adult population has stippling?

Answer 13

40%

Question 14

What is the gingival groove? Is it always present?

Answer 14

It is located at about the same level as the apical border of the JE
It does not correspond with the apical border of the gingival sulcus
It is not always present, inflammation can mask it

Question 15

What is the main role of the oral epithelium?

Answer 15

Protection against mechanical injury during mastication

Question 16

Describe the roles of the junctional epithelium. What makes it so unique?

Answer 16

• Ability to stick to 2 sides via DAT cells
• Role in homeostasis
• Porous due to wide intercellular spaces which allows cells to pass through
• Defence against micro-organisms and bacterial products via cell adhesion products, cytokines, proteases, natural antimicrobial peptides and proteins

Question 17

What makes up the majority of gingival connective tissue?

Answer 17

Type 1 collagen fibres ‘principal fibres’

Question 18

What is the gingival connective tissue also called?

Answer 18

Lamina propria

Question 19

What are the layers that make up the lamina propria?

Answer 19

Papillary layer : finger like projections of connective tissue that are contained within depressions on the under surface of the overlying epithelium
Reticular layer: Located between under surface and root surface

Question 20

What is the role of fibroblasts? Why are they so important in gingival connective tissue?

Answer 20

They are responsible for synthesis of connective tissue fibres and ground substance
They play a key role in the maintenance and remodelling of connective tissue