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Flashcards in Tys Deck (16)
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1
Q

Enamel tuft description

A

Hypomineralised, contain greater concentration of enamel proteins
Ribbon like structure, longitudinal to tooth acids, extend from DEJ 1/3 into enamel
Wavy look within enamel microstructure

2
Q

Relationship between cross striation and enamel prisms

A

Cross striations formed across adjacent enamel prisms

3
Q

Changes in dental pulp as tooth ages

A

Reduce cellularity
Calcification (pulp stone)
Odontoblasts down regulate
Decreased volume

4
Q

Key feature of PDL and associated clinical application

A

Contains cells with regenerative potential, can regenerate new cementum/bone/PDL through guided tissue regeneration

5
Q

What is the role of Hertwig’s epithelial root sheath

A

HERS grow horizontally into dental papilla to form epithelial diaphragm. Induce dental papilla to differentiate into odontoblasts which deposit radicular dentin. Secrete hyaline layer. Dental follicular cells attach to hyaline layer, induce differentiation to cementoblasts and periodontal fibroblasts. HERS disintegration signals start of cementogenesis

6
Q

Where are blood vessels in pdl derived from

A

Periapical area, gingiva, PDL of overlying deciduous teeth

7
Q

List the differences between oral mucosa and skin

A

Hair follicles, sweat glands, colour differences due to melanin production

8
Q

How is junctional epithelium different from oral epithelium

A

Larger cells, lesser desmosomes, lesser tonofilaments, wider gap junctions/intercellular spaces, no acid phosphatase activity, lower glycolytic enzyme activity

9
Q

Advantages and disadvantages of pulp being surround by dentine

A

Advantage: hard protective covering

Disadvantage: Low compliance of dentine, limited capability to respond to revere inflammatory reaction

10
Q

How does tertiary dentine aid in defence of pulp against carious lesion

A

Make dentine less permeable to reduce diffusion towards pulp

Maintain buffer zone

11
Q

Mantle dentine vs circumpulpal dentine

A

Mantle dentine is first formed dentine

Mantle dentine lower density, less mineralised. Circumpulpal dentine harder, less elastic.

Mantle dentine mineralised by vesicle mineralisation. Circumpulpal dentine mineralised by crystal growth (nucleation)

12
Q

Function of odontoblasts

A

Secrete dentine
Sensory organ - mechanical/thermoreceptor
APC to defend pulp

13
Q

Difference between mineralisation pattern of collagen in bone and dentine

A

Both have extrafibrillar calcification

Only dentine has intrafibrillar calcification/calcification in gap zones

14
Q

Describe PDL fibres

A

Reticular: form lattice in PDL, collagen 3
Oxytalan: more in teeth bearing abnormal occlusal load, immature elastic fibres
Principal: collagen 1, high turn over rate
Elastin: walls of blood vessels

15
Q

What are the 3 parts of alveolar bone histologically

A

Compact bone, bundle bone, trabecular bone

16
Q

Five functional roles played by bone

A

Structural support

Protection

Movement

Haemapoiesis

Calcium metabolism