Oral Bio 1,2,3

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What are the 3 types of bonding to tooth
bonding through micro mechanical retention to enamel. bonding to dentine. bonding by direct adhesive materials through chemical bonds
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what's the formula for hydroxyapatite. what is the enamel structure made of
ca10(po4)6(oh)2. tightly packed hydroxyapatite crystals
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what is the basic unit of enamel structure
enamel prism/rod
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what is the enamel prism made of
prism core and prism sheath
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what is the fact about enamel prisms
distribution of hydroxyapatite crystal orientations
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what is the prism core and prism sheath
prism core= tightly packed hydroxyapatite crystals. prism sheath= crystals less tightly packed. boundary of clearly different crystal orientations. more space for organic components
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where would you find the GNARLED ENAMEL
at the cusps- the prisms appear twisted around each other- greater strength
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draw the incremental growth lines 'striae of retzius'
look at pp1
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what do striae of retzius represent and what do accentuated lines result from
weekly growth. accentuated lines result from- systemic disturbance like illness. birth- neonatal line
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what is the perikymata
shallow furrow where the striae reach the surface
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what is imbrication lines of pickerill
ridges between perikymata
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what is the. direction of collagen. fibres in dentine
parallel to ADJ
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draw the collagen fibres and the dentinal tubules - include 1ry and 2ry curvature
look a pp1
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how would you describe deep dentine
more porous, wetter
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what are he 3 types of dentinal tubules
no cell process just dentinal fluid. odontoblast process. odontoblast process and nerves
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where would nerves in dentine be found
most nerves in pre-dentine/inner dentine in pulp horns
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what are the classifications of dentine
1. developmental- mantle dentine, circumpulpal dentine 2. 1ry,2ry,3ry dentine 3.tubule-peri tubular/ intra tubular and intertubular
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where is the mantle dentine found and what is it characterised by
adjacent to enamel. characterised by- large collagen fibrils at 90 degrees to the ADJ. ground substance not all of odontoblast origin. slightly less mineralised. it has matrix vesicles
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in circumpulpal dentine where is the ground substance from? how would you describe the direction of collagen fibrils in relation to ADj? talk abut the mineralisation in circumpulpal dentine
ground substance is from odontoblasts. collagen fibrils are parallel to the ADJ. for mineralisation- no matrix vesicles, heterogenous nucleation
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when is 1,2,3ry dentine formed
1ry- formed during tooth development- up to root completion. 2ry- formed after root completion. forms slowly throughout life of the tooth. 3ry- forms in response to plural insult
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what are the 2 types of tertiary dentine
rectionary (uses odontoblasts, slow formation) and reparative (existing odontoblasts destroyed, recruit newly differentiated odontoblasts, rapid formation and poor structure
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what is the function of tertiary dentine
remove pulp from stimulus
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where could peri tubular/intra tubular and inter tubular dentine be found
peri-around tubule inter tubular- between tubules
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what is sclerosis and how does it appear
tubules being blocked off (with calcified material), appears transparent
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what is the importance of the hybrid layer? what happens if the etched dentine is over dried
results in collapse of the collagen layer, this then results in reduced bond strengths
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describe the outer and inner dentine lesion
outer- very decalcified, degenerated collagen inner- decalcified, collagen intact
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describe the hybrid layer in caries affected dentine
thicker
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what happens to permeability as depth increases. what effect does wetness have on bond strength
increases. wetness reduces bond strength
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what effect does increased pulpal pressure have on bond strength
decreases the bond strength
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this is the start of oral bio 2. what is hunter schreger bands
an optical effect reflecting the sinusoidal path of enamel prisms in alternating sheets
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draw enamel tufts and enamel spindles
look at ppt 2
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what are the 4 lesion zones from the advancing front
transluscent zone, dark zone, body of lesion, surface zone
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oral bio 3 starts. what are dead tracts
odontoblasts die.emtpty tubules. sealed with reparative tertiary dentine. appear dark.
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draw incremental lines of von ebner, and contour lines of Owen - dentine
look at ppt 3
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look at interlobular dentine- and granular layer of tomes
ppt 3
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draw the zone of bacterial penetration, zone of destruction and zone of advancing front, in order
ppt 3
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what are the defence responses to dentine caries
reactionary tertiary dentine, translucent/ sclerotic zone- blocks tubules but if rapid progression- no sclerosis, odontoblasts die and possibly reparative tertiary dentine
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talk about the advancing front, zone of bacterial penetration and zone of destruction
advancing front: zone of demineralised dentine, acid demineralisation, no bacteria. Zone of bacterial penetration: bacteria in tubules. lateral spread via branched tubules. lactobacilli. zone of destruction: mixed bacterial population- 2ry infectors.
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continued
proteolytic enzymes. destroys organic matrix
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Card 2

Front

what's the formula for hydroxyapatite. what is the enamel structure made of

Back

ca10(po4)6(oh)2. tightly packed hydroxyapatite crystals

Card 3

Front

what is the basic unit of enamel structure

Back

Preview of the front of card 3

Card 4

Front

what is the enamel prism made of

Back

Preview of the front of card 4

Card 5

Front

what is the fact about enamel prisms

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