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Flashcards in Caroline Chang Deck (184)
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1
Q

What is cardiac output

A

Rate of blood flow from the heart: blood volume pumped from one ventricle in one minute

2
Q

What is peripheral vascular resistance and what causes it

A

Resistance to flow produced mainly by arterioles

3
Q

How do you calculate blood pressure

A

Cardiac output X Peripheral vascular Resistance

4
Q

What are the 4 main controls of arterial blood pressure

A

Autonomic nervous system
Capillary shift
Endocrine and neuroendocrine responses
Kidney fluid balance

5
Q

What term control over blood pressure does the autonomic nervous system have

A

Short term minute to minute control via negative feedback

6
Q

What is the flow of input of control of blood pressure by autonomic nervous system

A

Higher centres in brain send signals to….

Medulla which integrates these with info from mechano and baroreceptors and sends signals to….

Parasympathetic branch of vagus nerve
Or sympathetic efferent branches from spinal chord

7
Q

Where are mechanoreceptors and baroreceptors found

4

A

Carotid sinus
Aortic arch
Heart
Lungs

8
Q

What is capillary shift

What term of control does it have over BP

A

Pressure gradient along capillaries

Medium term minutes to hours

9
Q

What is the mechanism for capillary shift controlling blood pressure

A

When pressure falls too low fluid is absorbed from tissues into circulation to increase blood volume thus pressure

When pressure rises too high fluid lost from circulation to reduce blood volume thus pressure

10
Q

What does endocrine relate to

A

Hormones released via glands in one part of body travelling in blood to target organs

11
Q

What does neuroendocrine relate to

A

Endocrine systems with neural features

12
Q

What term of control do endocrine responses have

A

Medium and long term

13
Q

What are catecholamines and what do they do

A

Hormones secreted in response to sympathetic stimulation such as adrenaline and noradrenaline that increase cardiac output and peripheral resistance

14
Q

What type of hormone is aldosterone and how does it act

2

A

Adrenal cortical steroid hormone

Causes renal collecting duct of kidneys to conserve sodium ions, promote potassium ion secretion and regulate acid base balance to increase blood pressure

Promotes vasopressin release which increases water retention from kidneys and increases blood pressure

15
Q

Describe the renin angiotensin system

A

Hypotension (low blood pressure)
Angiotensin release from liver and renin release from kidneys
Renin converts angiotensin to angiotensin 1
Angiotensin1 converted to angiotensin 2 by ACE enzyme
Angiotensin 2 increases sympathetic activity, increases H2O retention, stimulates aldosterone release, causes vasoconstriction,increases ADH secretion

16
Q

What term of control is kidney fluid balance

How do kidneys regulate BP

A

Long term

Increase or decrease blood volume by renin angiotensin system

17
Q

How is renal blood flow regulated 3

A

Renin angiotensin aldosterone system

Pressure diuresis: blood pressure increase increases filtration through kidneys and urinary output

Pressure natriuresis: sodium secretion increases when blood pressure increases so less water reabsorbed to decrease blood pressure

18
Q

Define shock

A

Shock is a state in which arterial blood pressure is insufficient to maintain an adequate supply of blood to tissues

19
Q

Hypovolemic shock

A

Severe blood or fluid loss

20
Q

Cardiogenic shock

A

Heart can’t pump enough blood

21
Q

Septic shock

A

Sepsis leading to abnormally low blood pressure

22
Q

Distributive shock

A

Abnormal distribution of blood flow

23
Q

Anaphylactic shock

A

Allergic reaction

24
Q
At stage 1 haemorrhagic shock
How much blood volume lost
What is heart rate
What is blood pressure 
What is central Venus pressure 
Clinical signs?
A
Less than 10% blood volume lost
Normal 
Normal 
Unchanged 
Normal
25
Q
At stage 2 haemorrhagic shock
How much blood volume lost 
What is heart rate
What is blood pressure 
What is central Venus pressure 
Clinical signs?
A
10-19%
100-120
Normal 
Pressure decreases a little 
Clinical signs of over activity
26
Q
At stage 3 haemorrhagic shock 
How much blood volume lost 
What is heart rate 
What is systolic blood pressure 
What is central Venus pressure 
Clinical signs?
A
20-39%
120-140
100
Central Venus pressure decreases a lot 
Clinically restless
27
Q
At stage 4 haemorrhagic shock 
How much blood volume lost 
What is heart rate 
What is systolic blood pressure 
What is central Venus pressure 
Clinical signs?
A
Over 40%
Over 140
Over 80
Decreases majorly 
Unconscious
28
Q

How much blood lost during minor oral surgery and what stage of shock

A

10-30ml

Stage 1

29
Q

What are the local responses to stress

2

A

Inflammation

Repair

30
Q

What are the systemic responses to stress

3

A

Conserve fluid
Generate energy
Ebb phase- depression of enzyme activity and oxygen consumption
Flow phase- catabolic phase with fat and protein mobilisation and increased urinary nitrogen excretion and anabolic phase where fat and protein stores restored

31
Q

Where does the apex of the heart lie

A

Between 5th and 6th rib in 5th intercostal space lining up with middle of left clavicle

32
Q

Which arteries branch off the aorta

A

Left and right coronary artery branch off ascending aorta

Brachiocephalic artery dividing into right subclavian artery and right common carotid artery branches off arch of aorta

Left common carotid artery branches of arch
Left subclavian artery branches of arch

Descending aorta

33
Q

Properties of arteries

5

A

Thick walls
Thin lumen
Elasticity to maintain high blood pressure
Smooth endothelium lining so blood flows
Thick tunica media layer of smooth muscle

34
Q

Properties of veins

7

A

Thin walls
Large lumen
May have valves
Few elastic fibres
Walls contain lots of collagen for support
Thin tunica media layer of smooth muscle
Capacitance vessel containing most of blood volume

35
Q

Properties of arterioles

3

A

Link arteries and capillaries
More smooth muscle for vasoconstriction and vasodilation
Reduce blood pressure before capillaries

36
Q

Properties of capillaries

4

A

Link arterioles and venules
Large surface area
Walls single endothelial cell thick
Cross section larger than supplying arteriole to slow blood for diffusion

37
Q

Define systole

What are pressures at end

A

Contraction of the heart during which arteriole then ventricular pressure increased and blood is forced out, by the end low pressure in heart and high pressure in arteries

38
Q

Define diastole

What are the pressures in heart and arteries

A

Relaxation of the heart during which atria and ventricles fill and volume and pressure in heart build with low pressure in arteries

39
Q

What are the stages in the cardiac cycle blood flow

A

Deoxygenated blood enters R atrium through vena cava at low pressure
Tricuspid valve opens and RV fills
R Atrium contracts
RV contracts and tricuspid valve closes so deoxygenated blood forced through pulmonary valve to pulmonary artery to capillary bed of lungs
Oxy blood from lungs enters LA from pulmonary vein
Bicuspid valve opens and LV fills
LA contracts forcing blood into LV
LV contracts forcing oxygenated blood through aortic valve to aorta

40
Q

What is pulmonary circulation

A

Blood flow from heart to lungs to heart

41
Q

What is systemic circulation

A

Blood flow from heart to body to heart

42
Q

What is meant by the term compliance

A

The index of elasticity of large arteries

43
Q

What is Normal blood pressure value

A

Below 120 mmHg systolic

44
Q
What are the values for:
Elevated blood pressure 
Hypertension stage 1
Hypertension stage 2
Hypertensive crisis
A

120-129 mmHg systolic
130-139 mmHg systolic
140-180 mmHg systolic
Above 180 mmHg systolic

45
Q

What is the value for hypotension

A

Below 90 mmHg systolic

46
Q

What are the four components of blood and their % by volume

A

Erythrocytes 40-45%
Thrombocytes less than 5%
Leukocytes less than 5%
Plasma 55%

47
Q

Properties of erythrocytes

5

A

Deliver oxygen to tissues using haemoglobin
Small, 8 micrometers across so can squeeze through vessels
Bioconcave shape
No nuclei or organelles
Lifespan 100-120 days

48
Q

What hormone stimulates erythrocytes formation

How many red blood cells do humans have

How many cells by number %

A

Erythropoietin

20-30 trillion

70% cells by number

49
Q

What is the action of haemoglobin with partial pressure of oxygen

A

As partial pressure of oxygen increases % saturation of haemoglobin to oxyhemoglobin increases

50
Q

What is normal red blood cell count for men and women

A

Men = 4.7-6.7 million cells per microlitre

Women = 4.2-5.4 million cells per microlitre

51
Q

When does anaemia occur

A

When there are low levels of erythrocytes in circulation

52
Q

When does polycythemia occur

A

When haematocrit is high due to high erythrocytes production or low plasma levels

53
Q

What is sickle cell disease

A

A genetic condition in which red blood cells are misformed causing pain attacks, anaemia and organ damage due to red blood cells becoming trapped

54
Q

What is the major role of platelets or thrombocytes

A

Blood clotting

55
Q

How big are thrombocytes

How many platelets per microlitre of blood

A

2-3 micrometers

150 000 - 450 000 platelets per microlitre of blood

56
Q

What is thrombocytopenia

A

Low platelet count below 50 000 per micro litre of blood

These patients show excessive bleeding and bruising

57
Q

Where do leukocytes come from

A

Multipotent stem cells in bone marrow

58
Q

How many white blood cells do we have

A

3,500-10,500 cells per microlitre

59
Q

What is leukopenia

A

Less white blood cells than normal

60
Q

What is leukocytosis

A

More white blood cells than normal

61
Q

What are the types of white blood cell and when are they raised

A

Monocytes - raised in bacterial infection
Neutrophils- raised in bacterial infection
Eosinophils- raised in parasitic infection, asthma or allergic reaction
Lymphocytes- raised in viral infection and lowered in HIV
Basophils- raised in bone marrow conditions

62
Q

What is the main role of plasma

A

Maintaining osmotic balance

63
Q

What does blood plasma contain

5

A
Water
Proteins including antibodies 
Ions 
Hormones 
Dissolved gasses
64
Q

Types of primary bond

3

A

Covalent
Metallic
Ionic

65
Q

Types of secondary bonds

2

A

Van der waals

Hydrogen bonds

66
Q

How do you calculate stress

A

Stress = force / area

67
Q

How do you calculate elastic modulus

A

Elastic modulus = stress / strain

68
Q

How do you calculate strain

A

Strain = change in length/ original length

69
Q

What does the area under stress strain curve represent

A

Toughness

70
Q

What is meant by ductile materials

A

Extensive plastic deformation and energy absorption before fracture

71
Q

What is meant by brittle materials

A

Little plastic deformation and low energy absorbtion before fracture

72
Q

What is biocompatibility

What is bioactive
What is bioinert

A

Compatibility with a living tissue or system by not being toxic, injurious or physiologically reactive and not causing immunological rejection

Substance having biological effect
Substance with no biological effect

73
Q

Which licensing bodies establish specifications for dental materials on an international level

A

FDI
CEN
ISO

74
Q

Which licensing body measures clinically significant chemical and physical properties
How often must it be renewed

A

ADA

ADA deal of acceptance must be renewed every 1-5 years

75
Q

Which licensing body uses risk based classification system

A

FDA

76
Q

What does CE mark mean

A

The manufacturer declares that the product complied with essential requirements of the relevant European health, safety and environmental protection legislation

77
Q

What is meant by primary level of protection

Secondary level of protection

Tertiary level of protection

A

Protection against disease

Limiting progression and effects of disease

Rehabilitation with further preventive care

78
Q

When does systemic action of fluoride take place

A

Pre eruption

79
Q

What are the effects of systemic fluoride action

3

A

Reduces acid solubility
Cristalites larger and more stable
Effects tooth morphology creating shallower pits and fissures

80
Q

When does topical action of fluoride take place

A

Post eruption

81
Q

What are the effects of topical fluoride action

4

A

Reduced demineralisation
Increases remineralisation by forming Fluor paper it’s when in solution
Inhibits plaque bacteria growth and glycolysis
Inhibits bacteria synthesis of extra cellular polysaccharide

82
Q

How much toothpaste should a 0-3 year old use

Ppm at standard risk
Ppm at giving concern

A

Smear
No less than 1000ppm
1350-1500ppm

83
Q

How much toothpaste should a 3-6 year old use

What ppm at standard risk
What ppm giving concern

A

Small pea

Over 1000ppm twice a day
1350-1500ppm twice a day

84
Q

How much toothpaste should a 7 year old to adult use

What ppm at standard risk
What ppm giving concern

A

Large pea

1350-1500 twice a day
Giving concern 7-9 : 1500ppm
Giving concern 10-15 : 2800ppm
Giving concern 16+ : 5000ppm

85
Q

What level of fluoride is in fluoridated water

A

1ppm

86
Q

How does mild fluorosis present clinically and what level of water fluoridation causes it

A

Small white patch

2ppm

87
Q

How does moderate fluorosis present clinically and what level of water fluoridation causes it

A

White opacity of whole crown with some brown mottling

3-4ppm

88
Q

How does severe fluorosis present clinically and what level of water fluoridation causes it

A

White opacity of whole crown with brown mottling, pitting and hypoplasia
4ppm

89
Q

What is the certain lethal dose of fluoride toxicity

A

32-64 mg/kg body weight

90
Q

What is the hospitalise dose of fluoride

A

5mg/kg body weight

91
Q

What should you do if a child consumes large amounts of fluoride below 5mg/kg body weight

A

Drink large amounts of milk

92
Q

What is the ratio of powder/alloy phase to liquid/mercury phase in dental amalgam and what constitutes the alloy

A

1:1

Alloy- silver tin zinc copper

93
Q

What are the forms of alloy and how are they made

3

A

Large cut- cut by large from ingots to form chippings then heat treated to relieve stress

Spherical- alloy ingredients melted then sprayed in inert atmosphere

Admixed - mixture of lathe cut and spherical

94
Q

What is gamma phase and what is it’s role in amalgam

A

Ag3Sn silver tin

Reacts with mercury to form amalgam

95
Q

What is coppers role in amalgam

A

Improves hardness and strength

96
Q

What is zincs role in amalgam

A

Acts as scavenger by preventing oxidation of metals in alloy during manufacturing and delays expansion

97
Q

What is the amalgam setting reaction

A

Y + mercury ➡️ Y + Y1 + Y2

Ag3Sn + Hg ➡️ Ag3Sn + Ag2Hg3 + Sn7Hg

98
Q

What are the strengths of the components of amalgam and how does mercury effect this

A

Gamma and gamma1 have similar strength
Gamma 2 softer

More mercury yields more gamma 2 so weaker amalgam

99
Q

What factors decrease amounts of mercury in amalgam

2

A

Condensation gives 50% Hg

Spherical alloy gives 45% Hg

100
Q

What is creep in the context of amalgam

When does amalgam melt and creep

A

Deformation of amalgam restoration under load after it has set

Creeps at 40 degrees, melts at 80 degrees

101
Q

What creates amalgam with less creep

A

Less gamma 1 and gamma 2

102
Q

How can amalgam corrosion be advantageous

A

Can seal gaps to prevent against secondary caries

103
Q

Which phase of amalgam is corrosion linked with and what is the equation for this

A

Gamma 2

Y2 (Sn7Hg) + O2 in oral fluids ➡️ Sn salts + free mercury

104
Q

When was high copper amalgam introduced

A

1962

105
Q

How much copper does high copper amalgam contain

A

At least 12%

106
Q

What is added to traditional amalgam to form high copper amalgam and how does this effect setting reaction

A

Spherical alloy of AgCu

Used in eutectic phase to eliminate Y2

107
Q

What is the two stage setting reaction of high copper dental amalgam

A

Stage 1
Ag3Sn + Hg ➡️ Ag2Hg3 + Sn7Hg
Y + mercury ➡️ Y1 + Y2

Eutectic phase
Sn7Hg + AgCu ➡️ Cu6Sn5 + Ag2Hg3
Y2 + Eutectic ➡️ n + Y1

108
Q

What are the manufacturers variables in amalgam and how do they effect its properties
2

A

Composition, high copper amalgam have less creep and corrosion and higher strength, they don’t contain zinc so there is no delayed expansion but are prone to tarnish

Particle size and shape, smaller particles easier to carve but result in more mercury whereas coarse particles result in less mercury but are easily dislodged from surface

109
Q

When would practitioner decrease trituration time

A

To lengthen working time
If mix too hot
If mix too wet

110
Q

When would practitioner increase trituration time

A

To shorten working time

If mix too dry

111
Q

How much force should condensation of amalgam take

A

30-49N

112
Q

What is the minimum depth for an amalgam filling

What Cavo surface angle should be used

A

2mm

90 degrees

113
Q

What are the disadvantages of amalgam

9

A
Poor aesthetics 
Mercury toxicity 
High thermal conductivity 
Galvanic effects
Lack of adhesion so requires mechanical retention 
Limited lifespan 
Tooth fracture due to undermined enamel 
Recurrent caries
Marginal breakdown
114
Q

When where composites introduces

A

1960s

115
Q

What are the 3 components of composites

A

Organic resin
Inorganic filler
Coupling agent

116
Q

What is the organic resin matrix made up of

A

High viscosity monomers
Low viscosity monomers
Inhibitors
Activator/initiator systems

117
Q

Give examples of high viscosity monomers

3

A

MMA
Bis GMA
UDMA

118
Q

Give examples of low viscosity monomers

3

A

TEGDMA

EDMA

119
Q

What is the main inhibitor used in the organic matrix of composites

A

Hydoquinone

120
Q

What are the inorganic fillers composed of

A

Silica, quartz and silicate particles

121
Q

What are the effects of inorganic fillers on composite properties
6

A
Enhance mechanical properties 
Reduce thermal expansion coefficient 
Reduce polymerisation shrinkage 
Provide radiopacity
Provide antibacterial activity 
Improves aesthetics
122
Q

What does the coupling agent in composite do

A

Forms bonds between fillers and resin

123
Q

How are coupling agents chemically bifunctional

A

Two functional groups
Hydrolysable alkoxy group reacts ugh silica particles of filler
Methacrylate group forms carbon carbon double bond with monomers

124
Q

How are self curing composites activated

A

Chemical activator plus initiator produces free radicals for addition polymerisation

125
Q

How are light cure composites activated

A

Initiator creates free radicals during photochemical activation

126
Q

What is the light source for UV activated composite
What is the wavelength
What is depth of cute

A

Mercury discharge lamp
10-400 nanometers
2mm

127
Q

What is the light source for VLA activated composite
What is the wavelength
What is the depth of cure

A

Quartz halogen lamp
460-480nm
3-4mm

128
Q

What are the sizes of particle fillers from smallest to largest

A
Mani fillers
Micro fillers
Nano hybrid 
Hybrid
Small particle fillers
Macro fillers
129
Q

What is the effect of increasing filler load

A

Strength, toughness, durability and clinical performance increases
Thermal expansion coefficient and polymerisation shrinkage decreases
Increases viscosity
Increases radiopacity

130
Q

What is the effect of decreasing filler size

A

Increases surface smoothness and aesthetics

131
Q

What are the stages in applying composites

7

A
Cavity preparation 
Acid etching 
Primer
Bonding agent
Placing composite 
Curing
Final shaping
132
Q

Advantages of composites

3

A

Insoluble in oral fluids
High biocompatibility
Coloured to match tooth

133
Q

Disadvantages of composites

4

A

Polymerisation shrinkage
Allergic reactions if components leak
Don’t match mechanical properties of enamel
Can discolour over time

134
Q

Which are the major salivary glAnds and how much do they contribute to saliva
3

A

Parotid 25%
Submandibular 65%
Sublingual 5%

135
Q

What is the parotid duct called
What is the submandibular duct called
What is the sublingual duct called

A
Parotid = stensons 
Submandibular = whartons 
Sublingual = bartholins
136
Q

What shape is parotid gland and what is it’s innervation

A

Inverted pyramid

Parasympathetic supply from CN9 and 5

137
Q

What shape is submandibular gland and what is it’s nerve supply

A

J shaped

Parasympathetic supply from CN7 and 5

138
Q

What shape is sublingual gland and how is it innervated

A

Almond shaped

Parasympathetic should from CN7 and 5

139
Q

What type of saliva is produced by parotid gland and from which cell

Which cells line parotid gland

A

Serious watery secretion by serous acinar epithelial cells

Cuboidal cell lining

140
Q

What is amylase and lysozyme activity of saliva from parotid gland

A

High amylase, no lysozyme

141
Q

What type of saliva is produced by submandibular gland and from which cells

What cells line submandibular gland

A

Mixed serous and mucus from serous and mucus acinar epithelial cells

Columnar cell lining

142
Q

What is amylase and lysozyme activity in saliva from submandibular gland

A

Medium amylase activity, high lysozyme activity

143
Q

What type of saliva is produced by sublingual gland by which cells

Which cells line sublingual gland

A

Mucous predominately, produces by mucous acinar epithelial cells

Stratified cuboidal cell lining

144
Q

What is amylase and lysozyme activity of saliva produced by sublingual gland

A

Low amylase and low lysozyme activity

145
Q

What is the difference in roles of mucous and serous saliva

A

Mucous protects soft tissues whereas serous protects hard tissues and aids eating and digestion

146
Q

What does a secretory unit consist of

5

A

Acinus, myoepithelial cells, intercalated duct, striated duct, excretory duct

147
Q

What is meant by serous demilune

A

Serous cells can form cap over mucous cells in mixed glands

148
Q

What happens in acinus

A

Protein and mucous secretion

149
Q

What do myoepithelial cells of gland do

A

Sit over acinus with muscular features to help force saliva out

150
Q

What shape of epithelial cells is the intercalated duct formed of and what is it’s purpose

A

Simple cuboidal intercalated duct cells

Act as conduit from acini to striated duct

151
Q

What forms striations of striated duct

A

Mitochondrion rich areas

152
Q

What cells form striated duct

A

Large simple columnar cells with large nuclei

153
Q

What happens in striated duct

A

Sodium and chlorine reabsorption and hydrogen carbonate secretion

154
Q

What type of cells are excretory ducts made of

A

Stratified cuboidal

155
Q

What is the process of saliva production moving through secretory unit

A

Parasympathetic or sympathetic stimulation causes acinus to produce isotonic fluid
In striated duct potassium and hydrogen carbonate move into lumen and sodium and chloride move out of lumen
Saliva becomes hypotonic and moves into excretory duct

156
Q

What is the 2 stage model of saliva secretion

A

Stage 1
Acinar cells secrete fluid containing amylase and electrolytes called primary saliva

Stage 2
Salivary gland duct cells in striated duct reabsorb sodium chloride from lumen and secrete potassium hydrogen carbonate into lumen

157
Q

What is the difference between whole and ductal saliva

How much whole saliva produced a day

A

Whole is mixture of saliva from different sources, 1-1.5 litres produced a day

Ductal saliva is directly from duct opening so pure

158
Q

What is the difference between stimulated and un stimulated flow

A

Unstimulated/resting flow keeps mouth lubricated and moist and is produced by submandibular and sublingual glands, it is mucous

Stimulated saliva is produced by parotid gland, it is serous and makes up 80-90% saliva production

159
Q

Normal unstimulated flow
Low unstimulated flow

Normal stimulated flow
Low stimulated flow

A

0.3-0.4 ml per min
Below 0.1 ml per min

1-7 ml per min
Below 0.5 ml per min

160
Q

What percentage of saliva is water

A

99%

161
Q

What is the equation for demineralisation/remineralisation of enamel

A

Ca10 (PO4)6 OH2 🔁 10Ca2+ + 6PO42- + 2OH-

162
Q
Hydroxyapatite content of
Newly formed enamel 
Dentine
Cementum
Bone
Enamel
A

Dentine 70%
Cementum 70%
Bone 70%
Enamel 90%

163
Q

How does pH affect ionisation

A

Decrease in pH promotes ionisation leading to demineralisation
Increase in pH decreases ionisation leading to remineralisation

164
Q

What is critical pH of the oral environment

What is normal pH of oral environment

A

5.5

6-7

165
Q

How long after glucose attack does pH drop below critical value

How long after glucose attack is pH at safe level

How long after glucose attack does pH return to normal

A

2-3 mins

40mins

2 hours

166
Q

Which processes exhibit demineralisation/ionisation

5

A
Destructive carious lesions
Acid etch
Sialolithiasis
Dental erosion
Drinking carbonated drinks
167
Q

Which processes exhibit remineralisation

3

A

Recalcification of early lesions
Fluoride application
Calculus deposition

168
Q

What is the formula for carbonatoapatite

A

Ca5 (PO4 CO3) 3 (OH)

169
Q

What is the form of fluoroapatite

A

Ca10 (PO4)6 F2

170
Q

How does fluoride protect the tooth

3

A

Inhibits bacterial metabolism
Lowers critical value for demineralisation
Promotes remineralisation

171
Q

What are the effects of fluoride on dentine

3

A

Increases hardness
Reduce hypersensitivity
May inhibit collagen formation at high concentrations

172
Q

What are the tree theories of dental pain

A

Neural theory- dentine tubules in dentine contain nerve endings
Odontoblastic transduction theory- when odontoblast processes membrane excited release neurotransmitters to nerve endings in pre dentine, odontoblast zone and pulp
Hydrodynamic theory- rapid shifts in fluid in dentine tubules activates nerves in inner dentine

173
Q

What can varnish be used as
Advantages
Disadvantages

A

Liner
Low cost
Washes out at margins

174
Q

What can calcium hydroxide be used as
Advantages
Disadvantages

A

Liner , temporary cement
Low cost
Most effective when in contact with pulp

175
Q

What can zinc oxide Eugenol be used as
Advantages
Disadvantages

A

Liner, base, cement
Antibacterial, sealing ability
Unable to withstand condensation forces

176
Q

What can zinc oxyphosphate be used as

What can zinc polycarboxylate be used as

A

Base and cement

177
Q

What is a liner

A

Thin coating which acts as barrier to chemical irritants and bacteria to protect pulp

178
Q

What are properties of calcium hydroxide liner

4

A

PH12- very alkaline
Antibacterial
Direct pulp capping agent
Compatible with all materials

179
Q

What are bases

A

Layer that minimises bulk of restorative material by acting as barrier to chemical irritants and bacteria and providing thermal insulation

180
Q

What is the powder and liquid part of zinc oxide eugenol and what ratio are they mixed at

A

Powder part = zinc oxide and magnesium oxide
Liquid part= oils such as euginol
Mixed 3:1 ratio for 1 minutes

181
Q

What does a varnish do

A

Resin dissolved in organic solvent seals dentine tubules to reduce micro leakage

182
Q

Which temporary restoration materials last 3-4 days

A

ZOE
Zinc oxyphosphate
Zinc polycarboxylate

183
Q

Which temporary restoration materials last 6 months

A

GIC

184
Q

Which temporary restoration materials can also be used as permanent restorations

A

RMGIC

Compomers