Tooth Whitening

Question 1

what are extrinsic causes of tooth discolouration

Answer 1

smoking
teas
coffee
red wine
guinness
chromogenic bacteria

Question 2

what are intrinsic causes of tooth discolouration

Answer 2

fluorosis
tetracycline
non-vitality
dental materials

Question 3

what colour does the teeth go in primary teeth of a patient with porphyria

Answer 3

red

Question 4

who are the group of people who you can still see disoclouration effects caused by tetracyclines

Answer 4

teenagers - tetracyclines used as a treatment for acne

Question 5

what is the first method of treatment for trying to sort discoloured teeth

Answer 5

hygiene phase therapy

Question 6

what are two types of tooth bleaching

Answer 6

external vital bleaching
internal vital bleaching

Question 7

what is discolouration caused by

Answer 7

formation of chemically stable, chromogenic products in the tooth substance that are long chain organic molecules

Question 8

how does bleaching sort discoloured teeth

Answer 8

they oxidise the long chain organic molecules which leads to smaller molecules that are not pigmented

Question 9

what is the bleach used to whiten teeth

Answer 9

hydrogen peroxide

Question 10

what is then oxidising agent of hydrogen peroxide

Answer 10

HO2

Question 11

what other constituents are found in bleaching solutions

Answer 11

carbamide peroxide
urea
surfactant
preservative
flavour

Question 12

what is the active component of external bleaching solutions

Answer 12

carbamide peroxide which breaks down into hydrogen peroxide and urea

Question 13

what does urea do in the external bleaching solutions

Answer 13

increases pH so you dont end up with as acidic a solution

Question 14

what is the function of carbopol in bleaching agents

Answer 14

thickening agent so that the solution actually sticks to the teeth

Question 15

what is the function of potassium nitrate and calcium phosphate in bleaching agents

Answer 15

tooth desensitisation

Question 16

what factors affect the success of bleaching

Answer 16

time
cleanliness of tooth surface
concentration of solution
temperature

Question 17

what aspects of being dentally fit do you need to ensure before undertaking external bleaching

Answer 17

no leakage around carious cavity margins

Question 18

what are warnings you need to give the patient when whitening teeth

Answer 18

sensitivity
relapse
restoration colour
allergy
might not work
compliance with regime

Question 19

what are the two types of external bleaching

Answer 19

in office or at home

Question 20

what are advantages of in office bleaching

Answer 20

controlled by dentist
quick results

Question 21

what are disadvantages of in office bleaching

Answer 21

time consuming for dentist
can be uncomfortable
results wear off
expensive

Question 22

what needs to be used for protection when bleaching teeth

Answer 22

rubber dam or gingival mask to protect the gums

Question 23

what is laser whitening

Answer 23

good initial result due to dehydrating the teeth

Question 24

what concentration of hydrogen peroxide is used to bleach teeth

Answer 24

35%

Question 25

what is the concentration of carbamide peroxide gel that is used in at home bleaching

Answer 25

10-15%

Question 26

what is the maximum strength of solution allowed for at home bleaching

Answer 26

6%

Question 27

what material is used to form the mouthguards for at home bleaching

Answer 27

0.5mm thick soft acrylic

Question 28

how far away from the gingival margin should the mouthguard stop

Answer 28

1mm

Question 29

how much gel should patients put in their tray at home

Answer 29

1mm squared dot on buccal surface of each tooth

Question 30

how long does at home whitening trays need to be in for to work

Answer 30

2 hours at least, preferably overnight

Question 31

when can you bleach teeth

Answer 31

age related darkening mild fluorosis post smoking cessation tetracyclin staining

Question 32

when does sensitivity resolve from bleaching

Answer 32

2-3 days

Question 33

what are predictors of sensitivity

Answer 33

previous sensitivity high concentration of bleaching agent gingival recession

Question 34

why does tooth whitening wear off over time

Answer 34

the oxidised chromogens gradually reduce with time and return to their normal state

Question 35

is there damage to restorations during tooth whitening

Answer 35

no - but need to warn patients that the teeth will be bleached but the composite restorations they may have will not

Question 36

why might there be difficulty bonding to teeth that have been whitened

Answer 36

residual oxygen from peroxide remains within the enamel structure but gradually dissipates over time

Question 37

what is chlorine dioxide

Answer 37

a bleaching agent that we NEVER use as it strips the enamel of the tooth - has a pH of 3 and softens tooth surface

Question 38

what causes tooth to internally discolour

Answer 38

the dead pulp bleeds into dentine which diffuse and darken causing grey discolouration

Question 39

what are indications of internal non-vital bleaching

Answer 39

non-vital tooth adequate RCT no apical pathology

Question 40

what are contraindications of internal non-vital bleaching

Answer 40

heavily restored tooth staining due to amalgam

Question 41

what are advantages of internal non-vital bleaching

Answer 41

easy conservative patient satisfaction

Question 42

what are risks of internal non-vital bleaching

Answer 42

external cervical resorption due to diffusion of hydrogen peroxide through dentine into periodontal tissues - normally a potential risk in trauma

Question 43

how do you carry out internal non-vital bleaching

Answer 43

remove access cavity and GP from pulp chamber and 1mm below ACJ - place 1mm RMGIC over GP to seal canal and root dentine remove any dark dentine and etch place the bleach and then repeat until desired shade then replace GP with a whiter GP

Question 44

what percentage of phosphoric acid is used to etch internal surface of the tooth

Answer 44

37%

Question 45

what is placed in the canal to internally bleach the tooth

Answer 45

10% carbamide peroxide gel

Question 46

when should you rebook the patient in to reassess

Answer 46

1 week and repeat this for 3 or 4 visists

Question 47

when will you need to retreat internal bleaching

Answer 47

4-5 years

Question 48

what is combination bleaching

Answer 48

using external and internal bleaching at the one time

Question 49

what are micro-abrasions

Answer 49

removes discolouration limited to outer layers of enamel

Question 50

when would you use microabrasions

Answer 50

fluorosis post ortho demineralisation demineralisation with staining

Question 51

what percentage of HCl is used in microabrasion

Answer 51

18%

Question 52

what is the treatment for microabrasion

Answer 52

clean teeth and apply rubber dam mix 18% HCl with pumice apply to teeth and gently rub for 5 seconds per tooth wash and repeat up to 10 times

Question 53

what do you polish teeth with post HCL and pumice

Answer 53

fluoride prophy paste

Question 54

what is applied to teeth after micro abrasion treatment

Answer 54

fluoride gel or varnish

Question 55

advantages of micro abrasion

Answer 55

quick easy no long term problems

Question 56

disadvantages of micro abrasion

Answer 56

acid sensitivity only works for superficial staining

Question 57

what might you use instead of HCl in practice

Answer 57

37% phosphoric acid

Question 58

what is resin infiltration

Answer 58

you dont try to remove the surface layer - this is particularly used for white discolouration

Question 59

what is the treatment used for white spot lesions

Answer 59

resin infiltration

Question 60

what must happen prior to prescribing whitening solution

Answer 60

appropriate clinical examination to ensure patients teeth is free of dental pathology

Question 61

what percentage of hydrogen peroxide is it illegal to use for cosmetic purpose

Answer 61

anything over 6%

Question 62

when can products containing any more than 0.1% hydrogen peroxide not be used

Answer 62

under 18 years of age

Question 63

what are some consumer products that contain 0.1% hydrogen peroxide

Answer 63

mouthrinse

Question 64

what is the only way patients should be able to buy 6% hydrogen peroxide

Answer 64

from a dental practitioner - they should not be able to buy it directly

Question 65

what aspect of treatment should be supervised

Answer 65

the first cycle of treatment must be supervised

Question 66

who would you be prosecuted by if you were found to be using solutions containing more than 6% hydrogen peroxide

Answer 66

trading standards