Periodontal Tissues

Question 1

What does the periodontal tissues consist of?

Answer 1

• alveolar bone
• periodontal ligament
• cementum
• gingival tissues

Question 2

What is the PDL?

Answer 2

• dense fibrous connective tissue
• occupies periodontal space between tooth and alveolar bone: 0.2mm wide
• contains: cells, fibres, ground substance, water, nerves, blood vessels

Question 3

What are the different types of fibres in the PDL?

Answer 3

• oblique: from bone to tooth
• horizontal: neck of tooth
• alveolar crest: from alveolar crest to tooth
• dentoperiosteal: from cementum to periosteal tissues
• alveologingival: alveolar crest to gingival tissues
• dentogingival: tooth to gingivae
• circumferential: run around tooth
• apical: around apex
• inter-radicular: inbetween roots
• transeptal: attach tooth-tooth

Question 4

Answer 4

Question 5

Answer 5

Question 6

Answer 6

Question 7

What are the functions of the PDL?

What are the functions of alveolar bone?

Answer 7

• attachment: tooth-bone
• support: suspensory system, shock absorber
• sensory: heavily innervated

Alveolar bone: support teeth, when tooth removed, bone resorbs, left woth basal bone

Question 8

What is the green line indicating?

Answer 8

Cortical bone: impermeable, thick, dense bone

Trabecular bone: spongy, cancellous bone

Green line: lamina dura: bindle of bone full of collagen fibres, porous, appears as a dense line on radiographs

Question 9

What is the function of oral mucosa?

Answer 9

• Protection: mechanical, microbiological, chemical, prevents dehydration
• sensation: richly innervated
• secretion
• thermal regulation

Question 10

What two tissues comprise the oral mucosa?

What are the types of oral mucosa?

Answer 10

Epithelium and connective tissue

Types of mucosa:

• masticatory mucosa: hard palate, gingivae
• lining: FOM, lips, soft palate
• specialised (gustatory): dorsum of tongue

Question 11

Answer 11

Question 12

What are the features of masticatory mucosa?

Alveolar mucosa?

Answer 12

Gingival mucosa: masticatory

• thick epithelium
• keratinised
• pink
• firm, stippled

Alveolar mucosa: lining

• thin epithelium
• non-keratinised
• red
• loose, mobile, smooth

Question 13

Answer 13

Question 14

Where is the junctional epithelium?

What is sulcular epithelium key facts?

List some points about junctional epithelium:

Answer 14

Junctional epithelium: at base of gingival sulcus and attached to tooth

Sulcular Epithelium:

• stratified squamous
• non-keratinised
• shallow/no rete pegs, smooth
• cells tightly packed

Junctional epithelium:

• immature
• rapid turnover
• many intracellular spaces - upto 18% of epithelium has spaces
• leaks
• gingival crevicular fluid passes through - constantly feed plaque bacteria

Question 15

Answer 15

Question 16

What is cementum and its role?

What are the two types?

Answer 16

• mineralised tissue, covers tooth roots
• supports tooth
• no blood vessels or nerves
• resistant to resorption

Acellular cementum: laid down very slowly, near gingival margin

Cellular cementum: closer to apex, has spaces where cells were trapped