Tooth Whitening Flashcards
what are extrinsic causes of tooth discolouration
smoking
teas
coffee
red wine
guinness
chromogenic bacteria
what are intrinsic causes of tooth discolouration
fluorosis
tetracycline
non-vitality
dental materials
what colour does the teeth go in primary teeth of a patient with porphyria
red
who are the group of people who you can still see disoclouration effects caused by tetracyclines
teenagers - tetracyclines used as a treatment for acne
what is the first method of treatment for trying to sort discoloured teeth
hygiene phase therapy
what are two types of tooth bleaching
external vital bleaching
internal vital bleaching
what is discolouration caused by
formation of chemically stable, chromogenic products in the tooth substance that are long chain organic molecules
how does bleaching sort discoloured teeth
they oxidise the long chain organic molecules which leads to smaller molecules that are not pigmented
what is the bleach used to whiten teeth
hydrogen peroxide
what is then oxidising agent of hydrogen peroxide
HO2
what other constituents are found in bleaching solutions
carbamide peroxide
urea
surfactant
preservative
flavour
what is the active component of external bleaching solutions
carbamide peroxide which breaks down into hydrogen peroxide and urea
what does urea do in the external bleaching solutions
increases pH so you dont end up with as acidic a solution
what is the function of carbopol in bleaching agents
thickening agent so that the solution actually sticks to the teeth
what is the function of potassium nitrate and calcium phosphate in bleaching agents
tooth desensitisation
what factors affect the success of bleaching
time
cleanliness of tooth surface
concentration of solution
temperature
what aspects of being dentally fit do you need to ensure before undertaking external bleaching
no leakage around carious cavity margins
what are warnings you need to give the patient when whitening teeth
sensitivity
relapse
restoration colour
allergy
might not work
compliance with regime
what are the two types of external bleaching
in office or at home
what are advantages of in office bleaching
controlled by dentist
quick results
what are disadvantages of in office bleaching
time consuming for dentist
can be uncomfortable
results wear off
expensive
what needs to be used for protection when bleaching teeth
rubber dam or gingival mask to protect the gums
what is laser whitening
good initial result due to dehydrating the teeth
what concentration of hydrogen peroxide is used to bleach teeth
35%
what is the concentration of carbamide peroxide gel that is used in at home bleaching
10-15%
what is the maximum strength of solution allowed for at home bleaching
6%
what material is used to form the mouthguards for at home bleaching
0.5mm thick soft acrylic
how far away from the gingival margin should the mouthguard stop
1mm
how much gel should patients put in their tray at home
1mm squared dot on buccal surface of each tooth
how long does at home whitening trays need to be in for to work
2 hours at least, preferably overnight
when can you bleach teeth
age related darkening
mild fluorosis
post smoking cessation
tetracyclin staining
when does sensitivity resolve from bleaching
2-3 days
what are predictors of sensitivity
previous sensitivity
high concentration of bleaching agent
gingival recession
why does tooth whitening wear off over time
the oxidised chromogens gradually reduce with time and return to their normal state
is there damage to restorations during tooth whitening
no - but need to warn patients that the teeth will be bleached but the composite restorations they may have will not
why might there be difficulty bonding to teeth that have been whitened
residual oxygen from peroxide remains within the enamel structure but gradually dissipates over time
what is chlorine dioxide
a bleaching agent that we NEVER use as it strips the enamel of the tooth - has a pH of 3 and softens tooth surface
what causes tooth to internally discolour
the dead pulp bleeds into dentine which diffuse and darken causing grey discolouration
what are indications of internal non-vital bleaching
non-vital tooth
adequate RCT
no apical pathology
what are contraindications of internal non-vital bleaching
heavily restored tooth
staining due to amalgam
what are advantages of internal non-vital bleaching
easy
conservative
patient satisfaction
what are risks of internal non-vital bleaching
external cervical resorption due to diffusion of hydrogen peroxide through dentine into periodontal tissues - normally a potential risk in trauma
how do you carry out internal non-vital bleaching
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
what percentage of phosphoric acid is used to etch internal surface of the tooth
37%
what is placed in the canal to internally bleach the tooth
10% carbamide peroxide gel
when should you rebook the patient in to reassess
1 week and repeat this for 3 or 4 visists
when will you need to retreat internal bleaching
4-5 years
what is combination bleaching
using external and internal bleaching at the one time
what are micro-abrasions
removes discolouration limited to outer layers of enamel
when would you use microabrasions
fluorosis
post ortho demineralisation
demineralisation with staining
what percentage of HCl is used in microabrasion
18%
what is the treatment for microabrasion
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
what do you polish teeth with post HCL and pumice
fluoride prophy paste
what is applied to teeth after micro abrasion treatment
fluoride gel or varnish
advantages of micro abrasion
quick
easy
no long term problems
disadvantages of micro abrasion
acid
sensitivity
only works for superficial staining
what might you use instead of HCl in practice
37% phosphoric acid
what is resin infiltration
you dont try to remove the surface layer - this is particularly used for white discolouration
what is the treatment used for white spot lesions
resin infiltration
what must happen prior to prescribing whitening solution
appropriate clinical examination to ensure patients teeth is free of dental pathology
what percentage of hydrogen peroxide is it illegal to use for cosmetic purpose
anything over 6%
when can products containing any more than 0.1% hydrogen peroxide not be used
under 18 years of age
what are some consumer products that contain 0.1% hydrogen peroxide
mouthrinse
what is the only way patients should be able to buy 6% hydrogen peroxide
from a dental practitioner - they should not be able to buy it directly
what aspect of treatment should be supervised
the first cycle of treatment must be supervised
who would you be prosecuted by if you were found to be using solutions containing more than 6% hydrogen peroxide
trading standards
