Tooth Whitening Flashcards
What are the extrinsic causes of tooth discoloration
smoking tannins chromogenic bacteria chlorhexidine iron supplements
What are the tannins
tea
coffee
red wine
guinness
What are the intrinsic
fluorosis tetracycline non vitality blood products physiological dental materials porphyria cystic fibrosis thalassemia, sickle cell anaemia hyperbilirubinaemia
What are red primary teeth indicative of
porphyria
What are grey teeth indicative or
CF
What are blue green or brown teeth indicative of
thalassemia / sickle cell
What are green teeth indicative of
hyperbilirubinaemia
What should always be the first method of tooth whitening for extrinsic
hygiene phase therapy
What are the two types of tooth bleaching
external vital bleaching
internal non vital bleaching
can be used together in non vital teeth
What is the extrinsic discoloration due to
caused by formation of chemically stable, chromogenic products within the tooth substance
long chain organic molecules
What does vital external bleaching do
oxidizes the compounds
oxidation leads to smaller molecules which are often not pigmented
oxidation can cause ionic exchange in metallic molecules leading to lighter color
What is the active agent in vital external bleaching
hydrogen peroxide
How does hydrogen peroxide work
an acidic solution in water
breaks down to form water and oxygen
free radical per hydroxyl (HO2) is formed
this is the active oxidizing agent
What are the constituents of bleaching gel
carbamide peroxide carbopol urea surfactant pigment dispersers preservative flavour potassium nitrate calcium phosphate fluoride
What is carbamide peroxide
active ingredient
breaks down to produce hydrogen peroxide and urea
urea increases pH
What is carpool
thickening agent
slows the release of oxygen, increasing the viscosity of the gel and stays where you put it
it slows diffusion into enamel
What is the function of urea
raises pH
stabilises hydrogen peroxide
What is the function of surfactant
allows the gel to wet the tooth surface
What is the function of potassium nitrate and calcium phosphate
tooth desensitizing agents
What is the function of fluoride
prevents erosion
desensitizing effect
What are factors that effect bleaching
time
cleanliness of tooth surface
concentration of solution
temperature
What is the effect of time
more time = more effect
What is the effect of cleanliness of the tooth surface
cleaner –> better
What is the effect of concentration of solution
higher conc, more and quicker effect
What is the effect of temperature
higher –> quicker effect
What should you check before u start bleaching
that px is dentally fit
any leakage around carious cavity margins –> plural damage
take initial shade check and record in notes
What are warning for px on external vital bleaching
sensitivity relapse restoration color allergy might not work compliance with regime
What are the two types of vital external bleaching
chair side/in office
home
What are advantages of in office bleaching
controlled by px
can use heat or light
quick results
What are disdavtanges of in office bleaching
time for dentist
can be uncomfortable
results tend to wear off quicker
What is the technique for in office bleaching
clean teeth rubber dam/gingival mask apply bleaching gel to tooth apply heat / light wash/dry/repeat take 30 mins to an hour
When is heat / light / laser used
with in office bleaching
no evidence of better bleaching with these additional procedures
light and laser are really just heart sources
What are the good initial results with laser due to
dehydration
wears off quick
What does home vital bleaching use
10-15% carbide peroxide gel (16.7% is = 6%)
What are advantages of at home bleaching
custom made tray
bleaches slowly over several weeks
easy for dentist and px
What is the technique for the custom trays for at home bleaching
alginate impression
0.5mm thick soft acrylic vacuum formed soft splint made
should stop short of GM at 1mm
buccal spacer to allow for placement of gel
What is in surgery part of the technique for at home bleaching
full mouth cleansing and polishing of teeth in surgery
fit trays and check extension and comfort
instruction in use
What is the at home part of the technique for at home bleaching
brush and floss teeth
load tray with 1mm dot ducally on each tooth
fit tray in mouth
wear for at least 2 hrs, preferably overnight
What are the results for at home bleaching
usually see results within first 2-3 days
normally reached max by 3-4 weeks
if no change in 2 weeks then not going to work
When can we bleach
age related darkening and discoloration
mild fluorosis
post smoking cessation
tetra cyclin staining ?
What teeth with age related darkening respond better to tx
those with yellow / orange discoloration respond better than those with bluish/grey discoloration
What color of teeth with tetra cyclin staining respond better
prolonged tx
better with yellow and brown than grey
can take months
What are bleaching problems
sensitivity wears off cytotoxicity mutagenicity gingival irritation tooth damage damage to restorations problems with bonding to tooth
When is sensitivity worse
initially
resolves over 2-3 days post bleaching
What are predictors of sensitivity
pre existing sensitivity high conc of bleaching agent frequency change bleaching method gingival recession
Why does the effect wear off
oxidises chromogens gradually reduce with time
retreat in 1-3 yrs
What is the risk of cytotoxicity / mutageneicity
no evidence for 10% CP
high conc of HP can cause issues
What is the risk of gingival irrational
related to conc
must check tray extension is correct and it is to overextended
What are issues with restorations and bleaching
composite doesn’t bleach
px must be aware before
if u change restorations to match the bleached teeth, continued bleaching is required
What are issues with bonding
residual oxygen from the peroxide remains within the enamel structure initially
gradually dissipates over a short time
delay restorative procedures for at least 24h post bleaching
better to delay for a week
When should chlorine dioxide be used
never
What is the issue with chlorine dioxide
it has a pH of around 3 and will soften the tooth surface
as a result of chlorine dioxide use, the teeth are more prone to re-staining develop a rough surface and become extremely sensitive
What are causes of internal staining in non vital teeth
dead pulp bleeds into dentine and the blood products diffuse and darken leading to grey discoloration
What are indications for internal non vital bleaching
non vital tooth
adequate RCT
no apical path
What are contraindications of internal non vital bleaching
heavily restored teeth
better with crown or veneer
staining due to amalgam
What is limitations of internal non vital bleaching
doesn’t always work
worth a go
What are advantages of internal non vital bleaching
easy
conservative
px satisfaction
What are risks of internal non vital bleaching
easy
cosnervative
px satisfaction
What are risks of internal non vital bleaching
external cervical resorption
What is external cervical resorption due to
diffusion of hydrogen peroxide through dentine into periapical tissues
high conc of hydrogen peroxide and heat
trauma is important
What is the technique for internal non vital bleaching
record shade prophylaxis rubber dam remove filling from access cavity remove GP from pulp chamber and 1mm below ACJ place 1mm RMGIC over GP to seal canal remove any v dark dentine etch internal surface of tooth place 10% carbide peroxide in cavity cotton wool over this seal with GIC repeat procedure at weekly intervals
What is the function of the 1mm RMGIC over GP to seal the canal
seals dentine and prevent root resorption
When do we repeat the internal non vital bleaching until
required shade achieved
no change
can take 3-4 visits
if no change after 4 visits won’t work and consider crown
Once the final shade is obtained in the non vital bleaching what is done
restore palatal cavity place white GP or similar in pulp chamber restore with light shade of composite will gradually darken again retreatment every 4-5 years?
What is combination bleaching
inside outside bleaching
What is technique for combination bleaching
remove gp as before and cover with RMGIC
make bleaching tray (palatal not buccal reservoir)
bleach placed in access cavity and in tray
replaced frequently over about a week
tricky for px, must wear tray whole time
What is micro-abrasion
removes discoloration limited to outer layers of enamel
combination of erosion (acid) and abrasion (pumice
What are the indications of micro abrasion
fluorosis
post ortho demineralisation
demineralization with staining
prior to veneering if dark staining is present
What is the technique for micro abrasion
clean teeth thoroughly rubber dam (seal is v important) mix 18% HCL and pumice apply to teeth gently rub with prophylaxis cup 5 seconds/tooth wash repeat up to 10 x remove dam polish teeth with fluoride prophylaxis paste apply fluoride gel or varnish review after one month
Why is fluoride gel applied after micro abrasion
help re harden surface and decrease sensitive
What can be happen if micro abrasion is repeated too much
too much can lead to yellowing of tooth as dentine begins to show through
too much will lead to permanent sensitivy
What are advantages of micro abrasion
quick
easy
no longer term problems as long as u stick to outside
What are disadvantages of micro abrasion
acid
sensitivty
only works for superifical staining
works much better for brown staining than white marks
Why is HCL used over phosphoric in micro abrasion
HCL removes 100 microns, PA removes 10
What is resin filtration
don’t remove surface layer
infiltrate the white area with resin
changes the refractive index of the white area
masks it and makes it look like the surrounding enamel
How was resin infiltration used for treatment of white spot lesion
hydrophilic resin impregnation of the porous enamel surface in the white area
What are the adv and disadvantages of resin information
appears to demonstrate immediate masking effect
durability of aesthetic results requires longer term study
due to potential staining a
aging of low viscosity resins used
Why is an appropriate clinical exam carried out before whitening
free of dental pathology
medical contra indications
What are the medical contraindications
glucose-6-phosphate dehydrogenase deficiency
acatalesmia
neither group can metabolism hydrogen peroxide
What are the laws with tooth whitening
cannot contain more than 6% hydrogen peroxide
cannot use under age of 18 unless for prevention disease
What is % of hydrogen peroxide allowed on market
0.1%
How should the whitening products >00.1% be used
exposure to these products should be limited to ensure products are only used in terms of frequency and duration of applications
the products should not be directly available to the consumer, only through a dentist, hygienist, therapist, or clinical dental technician
What are the guidelines that must eb followed
whitening products must be sold by dentist
first cycle of tx must be supervised
after then can be used at home
cannot exceed 6% unless for prevention disease
