Caroline Chang Flashcards
What is cardiac output
Rate of blood flow from the heart: blood volume pumped from one ventricle in one minute
What is peripheral vascular resistance and what causes it
Resistance to flow produced mainly by arterioles
How do you calculate blood pressure
Cardiac output X Peripheral vascular Resistance
What are the 4 main controls of arterial blood pressure
Autonomic nervous system
Capillary shift
Endocrine and neuroendocrine responses
Kidney fluid balance
What term control over blood pressure does the autonomic nervous system have
Short term minute to minute control via negative feedback
What is the flow of input of control of blood pressure by autonomic nervous system
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
Where are mechanoreceptors and baroreceptors found
4
Carotid sinus
Aortic arch
Heart
Lungs
What is capillary shift
What term of control does it have over BP
Pressure gradient along capillaries
Medium term minutes to hours
What is the mechanism for capillary shift controlling blood pressure
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
What does endocrine relate to
Hormones released via glands in one part of body travelling in blood to target organs
What does neuroendocrine relate to
Endocrine systems with neural features
What term of control do endocrine responses have
Medium and long term
What are catecholamines and what do they do
Hormones secreted in response to sympathetic stimulation such as adrenaline and noradrenaline that increase cardiac output and peripheral resistance
What type of hormone is aldosterone and how does it act
2
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
Describe the renin angiotensin system
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
What term of control is kidney fluid balance
How do kidneys regulate BP
Long term
Increase or decrease blood volume by renin angiotensin system
How is renal blood flow regulated 3
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
Define shock
Shock is a state in which arterial blood pressure is insufficient to maintain an adequate supply of blood to tissues
Hypovolemic shock
Severe blood or fluid loss
Cardiogenic shock
Heart can’t pump enough blood
Septic shock
Sepsis leading to abnormally low blood pressure
Distributive shock
Abnormal distribution of blood flow
Anaphylactic shock
Allergic reaction
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?
Less than 10% blood volume lost Normal Normal Unchanged Normal
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?
10-19% 100-120 Normal Pressure decreases a little Clinical signs of over activity
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?
20-39% 120-140 100 Central Venus pressure decreases a lot Clinically restless
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?
Over 40% Over 140 Over 80 Decreases majorly Unconscious
How much blood lost during minor oral surgery and what stage of shock
10-30ml
Stage 1
What are the local responses to stress
2
Inflammation
Repair
What are the systemic responses to stress
3
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
Where does the apex of the heart lie
Between 5th and 6th rib in 5th intercostal space lining up with middle of left clavicle
Which arteries branch off the aorta
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
Properties of arteries
5
Thick walls
Thin lumen
Elasticity to maintain high blood pressure
Smooth endothelium lining so blood flows
Thick tunica media layer of smooth muscle
Properties of veins
7
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
Properties of arterioles
3
Link arteries and capillaries
More smooth muscle for vasoconstriction and vasodilation
Reduce blood pressure before capillaries
Properties of capillaries
4
Link arterioles and venules
Large surface area
Walls single endothelial cell thick
Cross section larger than supplying arteriole to slow blood for diffusion
Define systole
What are pressures at end
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
Define diastole
What are the pressures in heart and arteries
Relaxation of the heart during which atria and ventricles fill and volume and pressure in heart build with low pressure in arteries
What are the stages in the cardiac cycle blood flow
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
What is pulmonary circulation
Blood flow from heart to lungs to heart
What is systemic circulation
Blood flow from heart to body to heart
What is meant by the term compliance
The index of elasticity of large arteries
What is Normal blood pressure value
Below 120 mmHg systolic
What are the values for: Elevated blood pressure Hypertension stage 1 Hypertension stage 2 Hypertensive crisis
120-129 mmHg systolic
130-139 mmHg systolic
140-180 mmHg systolic
Above 180 mmHg systolic
What is the value for hypotension
Below 90 mmHg systolic
What are the four components of blood and their % by volume
Erythrocytes 40-45%
Thrombocytes less than 5%
Leukocytes less than 5%
Plasma 55%
Properties of erythrocytes
5
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
What hormone stimulates erythrocytes formation
How many red blood cells do humans have
How many cells by number %
Erythropoietin
20-30 trillion
70% cells by number
What is the action of haemoglobin with partial pressure of oxygen
As partial pressure of oxygen increases % saturation of haemoglobin to oxyhemoglobin increases
What is normal red blood cell count for men and women
Men = 4.7-6.7 million cells per microlitre
Women = 4.2-5.4 million cells per microlitre
When does anaemia occur
When there are low levels of erythrocytes in circulation
When does polycythemia occur
When haematocrit is high due to high erythrocytes production or low plasma levels
What is sickle cell disease
A genetic condition in which red blood cells are misformed causing pain attacks, anaemia and organ damage due to red blood cells becoming trapped
What is the major role of platelets or thrombocytes
Blood clotting
How big are thrombocytes
How many platelets per microlitre of blood
2-3 micrometers
150 000 - 450 000 platelets per microlitre of blood
What is thrombocytopenia
Low platelet count below 50 000 per micro litre of blood
These patients show excessive bleeding and bruising
Where do leukocytes come from
Multipotent stem cells in bone marrow
How many white blood cells do we have
3,500-10,500 cells per microlitre
What is leukopenia
Less white blood cells than normal
What is leukocytosis
More white blood cells than normal
What are the types of white blood cell and when are they raised
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
What is the main role of plasma
Maintaining osmotic balance
What does blood plasma contain
5
Water Proteins including antibodies Ions Hormones Dissolved gasses
Types of primary bond
3
Covalent
Metallic
Ionic
Types of secondary bonds
2
Van der waals
Hydrogen bonds
How do you calculate stress
Stress = force / area
How do you calculate elastic modulus
Elastic modulus = stress / strain
How do you calculate strain
Strain = change in length/ original length
What does the area under stress strain curve represent
Toughness
What is meant by ductile materials
Extensive plastic deformation and energy absorption before fracture
What is meant by brittle materials
Little plastic deformation and low energy absorbtion before fracture
What is biocompatibility
What is bioactive
What is bioinert
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
Which licensing bodies establish specifications for dental materials on an international level
FDI
CEN
ISO
Which licensing body measures clinically significant chemical and physical properties
How often must it be renewed
ADA
ADA deal of acceptance must be renewed every 1-5 years
Which licensing body uses risk based classification system
FDA
What does CE mark mean
The manufacturer declares that the product complied with essential requirements of the relevant European health, safety and environmental protection legislation
What is meant by primary level of protection
Secondary level of protection
Tertiary level of protection
Protection against disease
Limiting progression and effects of disease
Rehabilitation with further preventive care
When does systemic action of fluoride take place
Pre eruption
What are the effects of systemic fluoride action
3
Reduces acid solubility
Cristalites larger and more stable
Effects tooth morphology creating shallower pits and fissures
When does topical action of fluoride take place
Post eruption
What are the effects of topical fluoride action
4
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
How much toothpaste should a 0-3 year old use
Ppm at standard risk
Ppm at giving concern
Smear
No less than 1000ppm
1350-1500ppm
How much toothpaste should a 3-6 year old use
What ppm at standard risk
What ppm giving concern
Small pea
Over 1000ppm twice a day
1350-1500ppm twice a day
How much toothpaste should a 7 year old to adult use
What ppm at standard risk
What ppm giving concern
Large pea
1350-1500 twice a day
Giving concern 7-9 : 1500ppm
Giving concern 10-15 : 2800ppm
Giving concern 16+ : 5000ppm
What level of fluoride is in fluoridated water
1ppm
How does mild fluorosis present clinically and what level of water fluoridation causes it
Small white patch
2ppm
How does moderate fluorosis present clinically and what level of water fluoridation causes it
White opacity of whole crown with some brown mottling
3-4ppm
How does severe fluorosis present clinically and what level of water fluoridation causes it
White opacity of whole crown with brown mottling, pitting and hypoplasia
4ppm
What is the certain lethal dose of fluoride toxicity
32-64 mg/kg body weight
What is the hospitalise dose of fluoride
5mg/kg body weight
What should you do if a child consumes large amounts of fluoride below 5mg/kg body weight
Drink large amounts of milk
What is the ratio of powder/alloy phase to liquid/mercury phase in dental amalgam and what constitutes the alloy
1:1
Alloy- silver tin zinc copper
What are the forms of alloy and how are they made
3
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
What is gamma phase and what is it’s role in amalgam
Ag3Sn silver tin
Reacts with mercury to form amalgam
What is coppers role in amalgam
Improves hardness and strength
What is zincs role in amalgam
Acts as scavenger by preventing oxidation of metals in alloy during manufacturing and delays expansion
What is the amalgam setting reaction
Y + mercury ➡️ Y + Y1 + Y2
Ag3Sn + Hg ➡️ Ag3Sn + Ag2Hg3 + Sn7Hg
What are the strengths of the components of amalgam and how does mercury effect this
Gamma and gamma1 have similar strength
Gamma 2 softer
More mercury yields more gamma 2 so weaker amalgam
What factors decrease amounts of mercury in amalgam
2
Condensation gives 50% Hg
Spherical alloy gives 45% Hg
What is creep in the context of amalgam
When does amalgam melt and creep
Deformation of amalgam restoration under load after it has set
Creeps at 40 degrees, melts at 80 degrees
What creates amalgam with less creep
Less gamma 1 and gamma 2
How can amalgam corrosion be advantageous
Can seal gaps to prevent against secondary caries
Which phase of amalgam is corrosion linked with and what is the equation for this
Gamma 2
Y2 (Sn7Hg) + O2 in oral fluids ➡️ Sn salts + free mercury
When was high copper amalgam introduced
1962
How much copper does high copper amalgam contain
At least 12%
What is added to traditional amalgam to form high copper amalgam and how does this effect setting reaction
Spherical alloy of AgCu
Used in eutectic phase to eliminate Y2
What is the two stage setting reaction of high copper dental amalgam
Stage 1
Ag3Sn + Hg ➡️ Ag2Hg3 + Sn7Hg
Y + mercury ➡️ Y1 + Y2
Eutectic phase
Sn7Hg + AgCu ➡️ Cu6Sn5 + Ag2Hg3
Y2 + Eutectic ➡️ n + Y1
What are the manufacturers variables in amalgam and how do they effect its properties
2
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
When would practitioner decrease trituration time
To lengthen working time
If mix too hot
If mix too wet
When would practitioner increase trituration time
To shorten working time
If mix too dry
How much force should condensation of amalgam take
30-49N
What is the minimum depth for an amalgam filling
What Cavo surface angle should be used
2mm
90 degrees
What are the disadvantages of amalgam
9
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
When where composites introduces
1960s
What are the 3 components of composites
Organic resin
Inorganic filler
Coupling agent
What is the organic resin matrix made up of
High viscosity monomers
Low viscosity monomers
Inhibitors
Activator/initiator systems
Give examples of high viscosity monomers
3
MMA
Bis GMA
UDMA
Give examples of low viscosity monomers
3
TEGDMA
EDMA
What is the main inhibitor used in the organic matrix of composites
Hydoquinone
What are the inorganic fillers composed of
Silica, quartz and silicate particles
What are the effects of inorganic fillers on composite properties
6
Enhance mechanical properties Reduce thermal expansion coefficient Reduce polymerisation shrinkage Provide radiopacity Provide antibacterial activity Improves aesthetics
What does the coupling agent in composite do
Forms bonds between fillers and resin
How are coupling agents chemically bifunctional
Two functional groups
Hydrolysable alkoxy group reacts ugh silica particles of filler
Methacrylate group forms carbon carbon double bond with monomers
How are self curing composites activated
Chemical activator plus initiator produces free radicals for addition polymerisation
How are light cure composites activated
Initiator creates free radicals during photochemical activation
What is the light source for UV activated composite
What is the wavelength
What is depth of cute
Mercury discharge lamp
10-400 nanometers
2mm
What is the light source for VLA activated composite
What is the wavelength
What is the depth of cure
Quartz halogen lamp
460-480nm
3-4mm
What are the sizes of particle fillers from smallest to largest
Mani fillers Micro fillers Nano hybrid Hybrid Small particle fillers Macro fillers
What is the effect of increasing filler load
Strength, toughness, durability and clinical performance increases
Thermal expansion coefficient and polymerisation shrinkage decreases
Increases viscosity
Increases radiopacity
What is the effect of decreasing filler size
Increases surface smoothness and aesthetics
What are the stages in applying composites
7
Cavity preparation Acid etching Primer Bonding agent Placing composite Curing Final shaping
Advantages of composites
3
Insoluble in oral fluids
High biocompatibility
Coloured to match tooth
Disadvantages of composites
4
Polymerisation shrinkage
Allergic reactions if components leak
Don’t match mechanical properties of enamel
Can discolour over time
Which are the major salivary glAnds and how much do they contribute to saliva
3
Parotid 25%
Submandibular 65%
Sublingual 5%
What is the parotid duct called
What is the submandibular duct called
What is the sublingual duct called
Parotid = stensons Submandibular = whartons Sublingual = bartholins
What shape is parotid gland and what is it’s innervation
Inverted pyramid
Parasympathetic supply from CN9 and 5
What shape is submandibular gland and what is it’s nerve supply
J shaped
Parasympathetic supply from CN7 and 5
What shape is sublingual gland and how is it innervated
Almond shaped
Parasympathetic should from CN7 and 5
What type of saliva is produced by parotid gland and from which cell
Which cells line parotid gland
Serious watery secretion by serous acinar epithelial cells
Cuboidal cell lining
What is amylase and lysozyme activity of saliva from parotid gland
High amylase, no lysozyme
What type of saliva is produced by submandibular gland and from which cells
What cells line submandibular gland
Mixed serous and mucus from serous and mucus acinar epithelial cells
Columnar cell lining
What is amylase and lysozyme activity in saliva from submandibular gland
Medium amylase activity, high lysozyme activity
What type of saliva is produced by sublingual gland by which cells
Which cells line sublingual gland
Mucous predominately, produces by mucous acinar epithelial cells
Stratified cuboidal cell lining
What is amylase and lysozyme activity of saliva produced by sublingual gland
Low amylase and low lysozyme activity
What is the difference in roles of mucous and serous saliva
Mucous protects soft tissues whereas serous protects hard tissues and aids eating and digestion
What does a secretory unit consist of
5
Acinus, myoepithelial cells, intercalated duct, striated duct, excretory duct
What is meant by serous demilune
Serous cells can form cap over mucous cells in mixed glands
What happens in acinus
Protein and mucous secretion
What do myoepithelial cells of gland do
Sit over acinus with muscular features to help force saliva out
What shape of epithelial cells is the intercalated duct formed of and what is it’s purpose
Simple cuboidal intercalated duct cells
Act as conduit from acini to striated duct
What forms striations of striated duct
Mitochondrion rich areas
What cells form striated duct
Large simple columnar cells with large nuclei
What happens in striated duct
Sodium and chlorine reabsorption and hydrogen carbonate secretion
What type of cells are excretory ducts made of
Stratified cuboidal
What is the process of saliva production moving through secretory unit
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
What is the 2 stage model of saliva secretion
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
What is the difference between whole and ductal saliva
How much whole saliva produced a day
Whole is mixture of saliva from different sources, 1-1.5 litres produced a day
Ductal saliva is directly from duct opening so pure
What is the difference between stimulated and un stimulated flow
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
Normal unstimulated flow
Low unstimulated flow
Normal stimulated flow
Low stimulated flow
0.3-0.4 ml per min
Below 0.1 ml per min
1-7 ml per min
Below 0.5 ml per min
What percentage of saliva is water
99%
What is the equation for demineralisation/remineralisation of enamel
Ca10 (PO4)6 OH2 🔁 10Ca2+ + 6PO42- + 2OH-
Hydroxyapatite content of Newly formed enamel Dentine Cementum Bone Enamel
Dentine 70%
Cementum 70%
Bone 70%
Enamel 90%
How does pH affect ionisation
Decrease in pH promotes ionisation leading to demineralisation
Increase in pH decreases ionisation leading to remineralisation
What is critical pH of the oral environment
What is normal pH of oral environment
5.5
6-7
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
2-3 mins
40mins
2 hours
Which processes exhibit demineralisation/ionisation
5
Destructive carious lesions Acid etch Sialolithiasis Dental erosion Drinking carbonated drinks
Which processes exhibit remineralisation
3
Recalcification of early lesions
Fluoride application
Calculus deposition
What is the formula for carbonatoapatite
Ca5 (PO4 CO3) 3 (OH)
What is the form of fluoroapatite
Ca10 (PO4)6 F2
How does fluoride protect the tooth
3
Inhibits bacterial metabolism
Lowers critical value for demineralisation
Promotes remineralisation
What are the effects of fluoride on dentine
3
Increases hardness
Reduce hypersensitivity
May inhibit collagen formation at high concentrations
What are the tree theories of dental pain
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
What can varnish be used as
Advantages
Disadvantages
Liner
Low cost
Washes out at margins
What can calcium hydroxide be used as
Advantages
Disadvantages
Liner , temporary cement
Low cost
Most effective when in contact with pulp
What can zinc oxide Eugenol be used as
Advantages
Disadvantages
Liner, base, cement
Antibacterial, sealing ability
Unable to withstand condensation forces
What can zinc oxyphosphate be used as
What can zinc polycarboxylate be used as
Base and cement
What is a liner
Thin coating which acts as barrier to chemical irritants and bacteria to protect pulp
What are properties of calcium hydroxide liner
4
PH12- very alkaline
Antibacterial
Direct pulp capping agent
Compatible with all materials
What are bases
Layer that minimises bulk of restorative material by acting as barrier to chemical irritants and bacteria and providing thermal insulation
What is the powder and liquid part of zinc oxide eugenol and what ratio are they mixed at
Powder part = zinc oxide and magnesium oxide
Liquid part= oils such as euginol
Mixed 3:1 ratio for 1 minutes
What does a varnish do
Resin dissolved in organic solvent seals dentine tubules to reduce micro leakage
Which temporary restoration materials last 3-4 days
ZOE
Zinc oxyphosphate
Zinc polycarboxylate
Which temporary restoration materials last 6 months
GIC
Which temporary restoration materials can also be used as permanent restorations
RMGIC
Compomers
