ORAL BIOLOGY Flashcards

1
Q

DESCRIBE ENAMEL

A

an epithelial product, translucent, hard, brittle, non-vital

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2
Q

what is the makeup of an enamel prism

A

this is the basic unit of enamel (microscopically) - there is a CORE which is tightly packed and a SHEATH which is loosely packed. (packed hydroxyappatite crystals)

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3
Q

describe the meaning of aprismatic

A

this is the last and first formed enamel, it has NO PRISMS

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4
Q

what is the job of the gnarled enamel at the cusps of the teeth

A

provides strength as that is where most of the load is eg masrticatory force!

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5
Q

where the direction of the enamel prisms point out towards?

A

the PDL

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6
Q

enamel spindles are extensions of what?

A

they are extensions of dentinal tubules

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7
Q

what are the perikymata

A

these are the inward bumps

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8
Q

pickerill ridges

A

the outward bumps

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9
Q

enamel is best developed at where on the tooth

A

the cusps

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10
Q

what are the striae of retzius

A

incremental growth lines, if these are accentuated it means that there is a sign of illness etc etc

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11
Q

what are the different lesion zones of enamel caries

A

translucent zone, dark zone, body of lesion, surface zone

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12
Q

describe what happens at the translucent zone in enamel caries

A

it is the 1st carious change, few large pores, prism loss structure

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13
Q

what happens at the dark zone of enamel caries

A

quoline cant penetrate, demineralisation and remineralisation occuring here

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14
Q

what is happening at the body of the lesion in enamel caries

A

largest part of the zones and it is translucdent

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15
Q

surface zone - what is happening here in enamel caries

A

intact, highly mineralised

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16
Q

describe what happens to arrested enamel caries

A

there may have been a diet change, good plaque control, fluoride varnish placed. these are usually brown and wide

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17
Q

describe what happens during occlusal caries in enamel

A

due to the fissures in the teeth, these are usually hard to detect, 2 lesions whcih follow the prism direction.

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18
Q

describe dentine

A

collagen matrix, specialised connective tissue, strong and hard, tubules

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18
Q

describe dentine

A

collagen matrix, specialised connective tissue, strong and hard

19
Q

what is in dentinal tubules

A

can depend in which direction they go, we can have no cells only dentinal fluid, can have odontoblasts or odontoblasts AND nerves

20
Q

we can have primary curvature dentine tubules following onto what…….

A

secondary curvatures, within these we have lines of owen (following the curvatures)

21
Q

what do the collagen fibres play a role in within dentine

A

these run parallel to the ADJ and provide STRENGTH! - they also show the incremental lines of von ebner

22
Q

what are the 3 classifications of dentine

A

1) developmental dentin, 2) primary secondary and tertiary dentine, 3) peri and inter tubular dentine

23
Q

describe developmental dentine

A

2 parts = mantle - this is the 1st formed, adjacent to enamel, large collagen fibrils
2nd is circumpulpal - this makes up the REST of dentine, small collagen fibrils

24
Q

describe primary, secondary and tertiary dentine

A

primary - during development, up until the root
secondary - after root formation, develops slowly through life!
tertiary - responds to insult dentine! there are 2 parts to tertiary (reactionary which is SLOW forming and reparative which is FAST forming)

25
Q

describe peri and inter tubular dentine

A

peri = around tubules
inter - between tubules

26
Q

what is the smear layer of dentine

A

this is the debris formed on dentine from instrumentation, this can be removed with acid etch

27
Q

describe the process/layers into dentine caries

A

cavitated/bacteria enters, we then have the destruction zone (mainly bacteria here), zone of bacterial penetration (bacteria in tubules), then the advancing front (demineralisation - no bacteria)

28
Q

dentine bonding, describe it

A

fluid moves OUT of the tubules, protective from bacteria. we then have the smear layer which is dissolved by acid etch - DONT OVER DRY THE TEETH OR ESLE THE COLLAGEN COLLAPSES (this will create micromechanical retention) the acid etch will expose the collagen and tubules which creates a strong bond to resin.

29
Q

peridontium - what are the sharpeys collagen fibres

A

they are terminal ends of the principal fibres that extend into cementum and alveolar bone,

30
Q

what does the cementum do

A

it covers the root, supports the tooth, there are NO NERVES OR BLOOD VESSELS

31
Q

What is acellular and cellular cementum

A

acellular - inside/top - fully mineralised - cervical root is thin
cellular - outer/bottom - partially mineralised - apical and thicker

32
Q

what is a cementocyte?

A

this is trapped in cementum - only the outer surface has live cells
they are WITHIN LACUNAE (spider shaped cells) -

33
Q

what are LACUNAE

A

LACUNAE (spider shaped cells) - the small finger like projections from lacunae are called cannaluculi

34
Q

what is within the gingival sulcus

A

natural 3mm ppd (pathological), contains gingival crevicular fluid, it is non keratinised which means there is a rapid turnover/shed of tissue AND ALSO BACTERIA, it leaks!

35
Q

Describe pulp

A

it is part/from dentine formation, defence and repair, a connective tissue, sensory (lots of nerves and blood vessels!)

36
Q

structure of pulp -what composes it?

A

pulp horns, pulp chamber, apex (apex has an apical constrictor which stops pulp from reachinf the full apex of the tooth), root canals (2/3 in multi rooted teeth)

37
Q

describe the pulp layers

A

odontoblast layer (pre-dentine layer), cell free zone, cell rich zone, pulp core

38
Q

pulpal cells - odontoblast division - what is this controlled by?

A

TGF beta

39
Q

describe the role of the oral mucosa

A

protection, sensation, secretion

40
Q

what are the three types of mucosa we can get

A

lining, masticatory and specialised

41
Q

what structures do lining mucosa have on

A

lips, soft palate and FOM

42
Q

what structures do the masticatory mucosa have on

A

hard palate

43
Q

what structures do the specialised mucosa have on?

A

tongue

44
Q

describe NON-KERATINISED LINING MUCOSA

A

good absorption (eg GTN spray), it is flexible, few rete pegs, layers are - epithelium, lamina propria, submucosa, bone/muscle

45
Q

describe KERATINISED MASTICATORY MUCOSA

A

many rete pegs, thick lamina propia (anchored to bone), resists compression, immobile, layers are - epithelium, lamina propia, periosteum, bone.