Gingiva

Question 1

Describe the composition of epithelial tissue

Answer 1

• Epithelial tissues are thin tissues that cover all the exposed surfaces of the body
* The skin and oral cavity covering (mucosa) is composed of stratified squamous epithelial cells.
• The cells that make up epithelia are closely bound together through specialised structures called “tight junctions”
* They are free from blood vessels and nerves, and are supported by a connective tissue called the basement membrane

Question 2

Describe the functions of epithelial tissue

Answer 2

• The epithelial tissue protects underlying tissue from injury/ chemicals/ invading bacteria/ excessive water loss
• It has sensory nerve endings to provide sensation on skin, eyes, ears, nose, tongue
• It secretes substances such as enzymes, hormones and lubricating fluids
* Reduces friction to underlying tissue by acting as a barrier

Question 3

Explain the two types of epithelial cell attachment (junctions)

Answer 3

• Desmosomes: Join two epithelial cells together

* Hemidesmosomes: join epithelial cells to basal lamina

Question 4

Recall the characteristics of the oral epithelium

Answer 4

• It is made of stratified, squamous epithelium.
• Epithelial cells are constantly renewing themselves, with a turnover rate of 5-16 days
• Oral epithelium is specialised, and is aka mucosa.

Question 5

Describe the structure and function of junctional epithelium

Answer 5

The JE attaches the gingiva to enamel and cementum. It does so with hemidesmosomes. It forms a seal at base of the gingival sulcus or pocket, and thus serves as a protective barrier between plaque and connective tissue beneath.

Question 6

Describe the connection between the oral epithelium and connective tissue

Answer 6

The connection between oral epithelium and connective tissue appear as ridges known as “rete pegs” which extend from connective tissue into epithelial layer

Question 7

What are the characteristics of the rete pegs connection?

Answer 7

• It increases the surface area between the two tissues
• It increases the strength between the two tissues
* It decreases the distance between the bloody supply (in connective tissue) and the epithelium. Blood supply is carried through connective tissue, papilla

Question 8

Explain differences between keratinized and non-keratinized epithelial cells and name examples of each

Answer 8

• Keratinisation is when the cytoplasm in outermost epithelial cell is replaced by keratin, making is hard, stronger and waterproof. These cells have no nuclei. Examples include the hard palate, attached gingiva and dorsum of the tongue

Non keratinised epithelial cells have nuclei, and act as a cushion against mechanical forces. Examples include inner cheek, soft palate, lips, floor of mouth.

Question 9

Name the anatomical areas of the gingival EPITHELIUM and characteristics of each

Answer 9

• Oral epithelium: covers the outer surface of free gingiva and attached gingiva. It goes from the start of the gingival margin to the mucogingival junction.
• Sulcular epithelium: Begins at crest of gingival margin and stops at the edge of the junctional epithelium (JE). It has a shallow “pocket” of about 0.5 to 3 mm in depth. With periodontal disease, this space deepens and tissue becomes ulcerated.
• Junctional epithelium: Attaches gingiva to enamel or cementum of tooth with hemidesmosomes. It forms a seal at base of the gingival sulcus or pocket, and thus serves as a protective barrier between plaque and connective tissue.

Question 10

Recall and describe the 5 gingival fibre groups

Answer 10

• Circular: encircles the tooth like a ring. It helps maintain the shape and position of free gingiva
• Dentogingival: attaches gingiva to the teeth. It runs from the cementum on the root to the connective tissue of free gingiva
• Dentoperiosteal: It starts at the cementum/enamel junction, and anchors the tooth to the periosteum of the alveolar bone.
• Alveologingival: starts at the alveolar crest and extends to gingival connective tissue. It anchors the gingiva to the alveolar bone

*Transeptal: binds the cementum of one tooth, just above the alveolar crest, to the cementum of another tooth.

Question 11

Recall the functions of the gingival fibres

Answer 11

• Attaches the junctional epithelium to the tooth
• Attaches free gingiva to cementum and bone
• Withstand mastication while maintaining gingiva shape
* Controls positioning of the tooth by connecting adjacent teeth