Periodontal Tissues in Health

Question 1

What is the periodontium?

Answer 1

The supporting apparatus of the tooth

Question 2

What are the 4 tissues which make up the periodontium?

Answer 2

1. Gingiva
2. Periodontal ligament
3. Alveolar bone
4. Cementum

Question 3

What is the function of the interdental papilla?

Answer 3

Prevent food impaction

Question 4

What are the 2 types of gingiva?

Answer 4

1. Alveolar mucosa

2. Attached gingiva

Question 5

Describe the attached gingiva

Answer 5

Keratinised gingival tissue attached tightly to underlying alveolar bone

Question 6

Describe the 4 main clinical appearances of healthy gingiva

Answer 6

1. Pink
2. Stippled
3. Knife edged margin
4. Scalloped profile

Question 7

Describe 2 overall functions of the gingiva

Answer 7

1. Provide attachment between oral mucous membrane and dental hard tissues
2. Protects underlying periodontal tissues from invasion by bacteria present in oral cavity

Question 8

What are the 3 distinct types of the gingival epithelium?

Answer 8

1. Junctional epithelium
2. Sulcular epithelium
3. Oral gingival epithelium

Question 9

Which part of the gingival epithelium is free?

Answer 9

Oral gingival epithelium

Question 10

What cells make up the junctional eptithelium?

Answer 10

Stratified non keratinised cells approximately 1mm in length

Question 11

Describe 2 functions of junction epithelium

Answer 11

1. Forms the attachment of the gingiva to the tooth surface

2. Defence role against bacterial invasion

Question 12

Describe the cells which make up the sulcular epithelium

Answer 12

Stratified squamous non-keratinised epithelium

Question 13

What is the approximate depth of sulcular epithelium?

Answer 13

0.5-2mm in depth

Question 14

Describe the cells of the oral gingival epithelium

Answer 14

Stratified squamous keratinised epithelium

Question 15

Name 5 components of the gingival connective tissue

Answer 15

1. Fibroblasts
2. Many blood vessels
3. Nerve cells
4. Collagen fibres bedded in extra cellular matrix
5. GAGs, proteoglycans and glycoproteins

Question 16

Describe the relationship between fibroblasts and periodontal connective tissues

Answer 16

Major cell types in periodontal connective tissue which secretes all components of extracellular matrix

Question 17

What are 5 types of collagen fibres in periodontal connective tissues?

Answer 17

1. Circular fibres
2. Dentogingival fibres
3. Alveolar crestal fibres
4. Dentoperiosteal fibres
5. Transceptal fibres

Question 18

What is the periodontal ligament?

Answer 18

Fibrous attachment which inserts into the tooth and alveolar bone

Question 19

What types of joint is the periodontal ligament?

Answer 19

Gomphosis as it allows some movement but is not from bone to bone

Question 20

What are Sharpey’s fibres?

Answer 20

End of ligament fibres embedded into bone which are mineralised

Question 21

What is the primary function of the periodontal ligament?

Answer 21

Supportive role of tooth, protecting against resorption and remodelling role

Question 22

Describe 3 features of the alveolar bone proper

Answer 22

• Thin lamella of bone surround root of tooth
• Attachment to principle fibres of PDL
• Perforated due to ingress of nerves and vessels

Question 23

What are 3 components of alveolar bone?

Answer 23

1. Alveolar bone proper
2. Cancellous bone
3. Cortical plates

Question 24

What is the function of cancellous bone of alveolar bone?

Answer 24

Surrounds the alveolar bone proper and gives support to the socket

Question 25

Describe the cancellous bone of the alveolar bone

Answer 25

Spongy bone consisting of widely spaced concentric or transverse lamella enclosing marrow spaces

Question 26

Describe cortical plates of the alveolar bone

Answer 26

Facial and lingual plates of compact bone forming the outer and inner plates of alveolar bone

Question 27

What cells are responsible for resorption of alveolar bone?

Answer 27

Multi-nucleated osteoclasts residing in Howships lacunae

Question 28

What 2 cells are responsible for deposition of alveolar bone?

Answer 28

1. Osteoblasts | 2. Osteoprogenitor cells

Question 29

Give an overview of cementum

Answer 29

- Calcified mesenchymal tissue covering entire root surface - Avascular and not innervated - Formed slowly throughout life - Thicker at apices - Resistant to resorption

Question 30

Name 2 types of cementum

Answer 30

1. Acellular | 2. Cellular

Question 31

Describe acellular cementum

Answer 31

- Forms a thin layer often confined to cervical portions of the root - Doesn't contain cementocytes but cementoblasts can be found on surface

Question 32

Describe cellular cementum

Answer 32

- Contains cementocytes in lacunae | - Communicate with each other through network of canaliculi

Question 33

What is hypercementosis?

Answer 33

Increased deposition of cementum generally around the apical regions of the tooth