tooth whitening Flashcards
2 types of causes of tooth discolouration
extrinsic and intrinsic
5 extrinsic sources of tooth staining
- smoking (commonest)
- tannins
- tea
- coffee
- red wine
- guiness
- chromogenic bacteria (younger)
- chlorohexidine
- iron supplements
9 intrinsic causes of tooth discolouration
- Fluorosis
- Tetracycline rarer now, can be acne teens, bands
- Non-vitality (blood products)
- Physiological (age changes)
- Dental Materials
- Amalgam
- Root filling materials
- porphyria (red primary teeth)
- cystic fibrosis (grey teeth)
- Thalassemia, Sickle Cell anaemia (blue, green or brown teeth)
- Hyperbilirubinaemia (green teeth) rare
cause of this tooth discolouration
pipe smoking
higher tar contant so greater discolouration than regular cigarettes
EX
cause of this tooth discolouration
black stain by chromogenic bacteria
EXO
cause of this tooth discolouration
tetracycline staining
see in bands - relates to formation of tooth and time tetracylcine given
cause of this tooth discolouration
porphyria
red primary teeth
cause of this tooth discolouration
fluorsis
quite common in some regions
INT
first method for tooth whitening
non and minmally invasive methods of treatment
hygiene phase therapy - scaling
can be all that is needed
2 types of tooth bleaching
external vital bleacing
internal non-vital bleaching
can be used together in non-vital teeth
simplest tooth bleaching method
external vital bleaching
how does external vital bleaching work
Discolouration is caused by the formation of chemically stable, chromogenic products within the tooth substance.
- These are long chain organic molecules.
Bleaching oxidises these compounds.
- Oxidation leads to smaller molecules which are often not pigmented
- Oxidation can cause ionic exchange in metallic molecules leading to lighter colour.
active agent in bleaching
hydrogen peroxide H2O2
H2O2 in external vital bleaching
Forms an acidic solution in water
- Breaks down to form water and oxygen
Free radical per hydroxyl (HO2)is formed.
- This is the active oxidising agent.
Fast reacting oxidising agent
- Used as bleaching agent in industry
- Used to bleach hair
- Used as a disinfectant
Seldom an ingredient in modern tooth bleaching products.
active oxidising agent in H2O2
Free radical per hydroxyl (HO2)is formed.
Fast reacting oxidising agent
- Used as bleaching agent in industry
- Used to bleach hair
- Used as a disinfectant
seldom an ingredient in modern tooth bleaching products
3 uses of free radical hydroxyl (HO2) formed from H2O2
- Used as bleaching agent in industry
- Used to bleach hair
- Used as a disinfectant
seldom an ingredient in modern tooth bleaching products
H2O2 in water
acidic solution formed
breaks down to form water and oxygen
free radical hydroxyl (HO2) is formed
10 constituents of bleaching gel
- Carbamide peroxide
- Carbopol
- Urea
- Surfactant
- Pigment dispersers
- Preservative
- Flavour
- Potassium Nitrate
- Calcium Phosphate
- Fluoride
active ingredient in vital external bleaching
carbamide peroxide
how is carbamide peroxide the active ingredient in external vital bleaching
breaks down to produce hygrogen peroxide and urea
10% carbamide peroxide ->
3.6% H2O2 + 6.4% Urea
role of urea as a breakdown substance of carbamide peroxide
Urea increases pH – counteracts acidification of solution by H2O2
carbopol role in vital external bleaching
Thickening agent – prevent sliding off
Slows the release of oxygen
Increases the viscosity of the gel so stays where you put it
- Stays on teeth
- Keeps bleaching agent on tooth for longer
- Stays in tray
Slows diffusion into enamel
urea role in external vital bleaching
raises pH
stabilises hydrogen peroxide
surfactant in external vital bleaching
allows gel to wet the tooth surface
potassium nitrate and calcium phophate
in external vital bleaching
tooth desensitising agents
sensitivity problem in tooth whitening
fluroide role in external vital bleaching
prevents eroision
densensitising effect
4 factors affecting bleaching
time
cleanliness of tooth surface
concentration of solution
temperature
time effect on bleaching
more time -> more effect
cleanliness of tooth surface effect on bleaching
cleaner -> better
nothing in between tooth and bleach
temperature effect on bleaching
higher -> quicker effect
concentration of solution effect on bleaching
higher concentration -> more and quicker effect
what to do before start any tooth whitening procedure
Before you start always check patient is dentally fit.
- Any leakage around carious cavity margins will lead to pulpal damage
once pt deemed dentally fit for tooth whitening
what is the intial stage of the procedure
Take an initial shade, agree it with the patient and record it in their notes.
Better still take a photo with a shade guide included in the picture
- Prevents future disagreement
why take shade before commencing any treatment
- Dehydration of tooth from rubber dam emphasise change*
- tooth no longer natural colour*
- Remember to select shade before doing any work
6 warnings for pt about external vital bleaching
- Sensitivity
- Relapse
- Restoration colour
- Allergy
- Might not work
- Compliance with regime
what to say about sensitivity post external vital bleaching
won’t last forever
worse intially
restoration colour and external vital bleaching
doesn’t change like organic tooth
2 types of external vital bleaching
chair side/in office
home
3 advantages of in office external vital bleaching
controlled by dentist
can use heat/light - help speed up process
quick results for pt
4 disadvatages of in office external vital bleaching
time for dentist - 1hr of dentist not really doing much
can be uncomforatble - dam, open for long
results tend to wear off quicker - dehydration of tooth in procedure emphasises change
expensive
in office external vital bleaching procedure
- Thorough cleaning of teeth
- Ideally rubber dam
- At least gingival mask – light cure guard
- Apply bleaching gel to tooth
- Apply heat/light
- Wash/dry/repeat
- Takes 30mins to an Hour
heat/light/laser in external vital bleaching
- Often used with In-office bleaching
- Mainly a marketing technique
- No evidence of better bleaching with these additional procedures
- Light and Laser are really just heat sources
- Often a good initial result
- Mainly due to dehydration
- Wears off quickly
what is essential in external vital bleaching
protection of gingiva
esp as everything is very dry
- Historically higher concentrations of bleaching gel were used 35% H2O2
- now 6% max
- Even with weaker solutions care is necessary
home vital bleaching uses
commonest
10%-15% Carbamide Peroxide Gel
-
16.7% Carbamide Peroxide equates to 6% hydrogen peroxide which is the maximum strength of solution. 15% tends to be the highest accessible
- Anything stronger than this is illegal
- Patient uses solution at home
- Custom made tray
- Bleaches slowly, over several weeks
- Easy for dentist and patient
16.7% carbamide peroxide =
6% hydrogen peroxide which is the maximum strength of solution.
15% tends to be the highest accessible (10-15% in home vital bleaching kits)
commonest bleaching technique
home vital bleaching
home vital bleaching requires what to be made
custom made set of mouth guards are required
- Alginate impressions of teeth
- 0.5mm thick soft, acrylic, vacuum formed soft splint made
Should stop short of gingival margin (1mm)
- Don’t want bleaching solution to be in contact
Buccal spacer to allow for placement of gel
important design of home bleaching guard
should stop short of gingival margin (1mm)
Don’t want bleaching solution to be in contact
type of custom made mouth guard for home vital bleaching
0.5mm thick soft, acrylic, vacuum formed soft splint made
from alginate impressions
3 stages of home vital bleaching procedure
make custom vacuum formed splint
surgery app
home care
steps in surgery before home vital bleaching
- Full mouth cleaning/polishing of teeth in surgery
- Fit trays and check extension/comfort
- Instruction in use
- Clear written instructions given
- Review at 1 week
home steps for home vital external bleaching
- Brush and floss teeth
- Load tray
- 1mm2 dot buccally on each tooth – only a small amount
- No advantage to having excess, no harm to swallow
- 1mm2 dot buccally on each tooth – only a small amount
- Fit tray in mouth
- Requires to be in place for at least 2 hrs
- Preferably overnight
how much gel should be placed in home vital bleaching splint
1mm2 dot buccally on each tooth – only a small amount
No advantage to having excess, no harm to swallow
results of home vital bleaching kits
Results are variable
- Most patient see a result within 2 – 3 days
- Normally reached maximum by 3 – 4 weeks
If no change in 2 weeks it is not going to work
when to bleach?
4 factors
- age related darkening/discolouration
- mild fluorisis light brown stains
- stopped smoking
- tetracyclin staining
age impact on bleaching decision
more exposure to extrinsic stains
Teeth with yellow/orange discolouration respond better than those with bluish/grey discolouration
when to bleach smokers
don’t bleach active smokers - waste of time
only bleach smokers when successfully stopped
when to bleach tetracyclin stains
debatable - pt choice ultimately
- Prolonged treatment
- Better with yellow and brown than grey
- Can take months
8 problems with bleaching
- Sensitivity
- Wears off
- Cytotoxicity/Mutagenicity
- Gingival irritation
- Tooth damage
- Damage to restorations
- Problems with bonding to tooth
- pt expectations need to be realistic
sensitivity in bleaching
- Common 60%+ most
- Worse initially
- Resolves over 2-3 days post bleaching
*
how can bleach induced sensitivity be managed
Few have to stop treatment due to it
Can do bleach day, day off, bleach day, day off
- Needs regular to work (weeks off doesn’t work)
5 predictors for pts being sensitive after bleaching
- Pre-existing sensitivity
- High concentration of bleaching agent
- Frequency of change – change solution multiple times quickly
- Bleaching method
- Gingival recession
issue of bleaching wearing off
- Oxidised chromogens gradually reduce with time
- Retreatment 1-3 years, varies
cytotoxic/mutagenicity risk of bleaching
carcinogenic risk
- No evidence for 10% Carbamine peroxide
- High conc H2O2 can cause problems not in dental conc
gingival irritation in bleaching
tend to be uncommon
related to conc
must check tray extension correct (1mm short of gingival margin)
tooth damage and bleaching
no evidence and been in use for 15+ years
damage to restorations from bleaching
Probably not
Teeth bleach, composite doesn’t.
- Patients must be aware of this before treatment starts
If you change the restorations to match the bleached teeth continued bleaching will be required or fillings will be too light in colour - cycle
problems with bonding and bleaching
Residual oxygen from the peroxide remains within the enamel structure initially
Gradually dissipates over a short time
- Delay restorative procedures for at least 24hrs post bleaching
- Better to delay for a week
Oxygen inhibited layer when bond to composite normally - REVISE
what is chlorine dioxide
product used in some beauty salons and cruise liners
NEVER USE
issue with chlorine dioxide
Softens and strips enamel from tooth surface
- Chlorine dioxide has a pH of around 3 and will soften the tooth surface.
As a result of chlorine dioxide use,
- teeth are more prone to re-staining,
- develop a rough surface and become extremely sensitive.
causes of internal discolouration
dead pulp -> bleeding into dentine
- blood products diffuse and darken
- grey discolouration
indications for internal non-vital bleaching (3)
- non-vital tooth
- adeqaute RCT
- no apical pathology
what is internal non-vital tooth bleaching trying to do
dead pulp -> bleeding into dentine
- Blood products diffuse and darken
- Grey discolouration
Try to oxidise blood products to get back to correct tooth colour
2 contraindications to internal non-vital tooth bleaching
- Heavily restored tooth
- Better with crown or veneer
- staining due to amalgam
limitation of internal non-vital tooth bleaching
doen’t always work but generally worth a go as non-invasive
unsure why
3 advantages of internal non-vital tooth bleaching
- Easy
- Conservative
- Patient satisfaction
risk in internal non vital tooth bleaching
external cervical resorption - not common
due to diffusion of H2O2 through dentine into periodontal tissue
tend to be seen more in
- high conc H2O2
- trauma
less heat and lower conc used now = lower risk
technique for internal non-vital tooth bleaching
- Record shade
- Prophylaxis, clean externally
- Rubber dam
- Remove filling from access cavity
- Remove GP from pulp chamber and 1mm below amelo-cemental junction
- Place 1mm RMGIC over GP to seal canal
- Seals dentine and prevents root resorption
- Prevent leaching of H2O2
- Seals dentine and prevents root resorption
- Remove any very dark dentine
- Etch the internal surface of the tooth with 37% phosphoric acid
- Open pores in dentine
- Place 10% carbamide peroxide gel in cavity
- Cotton wool over this
- Seal with GIC
Repeat procedure at weekly intervals
how long to repeat internal non-vital tooth bleaching
- Repeat until
- Required shade achieved
- No change
Normally takes 3 – 4 visits.
If no change after 4 visits it is not going to work and consider crown /veneer/ composite build up.
how much GP to remove from pulp chamber in internal non vital tooth bleaching
all GP from pulp chamber and 1mm below ACJ
why place 1mm RMGIC over GP
to seal canal
seals dentine and prevents root resorption and leaching of H2O2
etch with
37% phosphoric acid
reason for etching in internal non-vital bleaching
open pores in dentine
temporary seal between internal non vital appoinments
GIC
on achieving required shade in internal non-vital tooth bleaching then
restore the palatal cavity
- Place white GP or similar in pulp chamber
- Restore with light shade of composite
But ensure easy to regain access – as not permanent
Will gradually darken again
- Retreatment every 4 – 5 years? Variable
combination bleaching
Inside-outside bleaching
- Remove GP, as before, cover with RMGIC
- Make bleaching tray
- Palatal not buccal reservoir
- Bleach placed in access cavity and in tray
- Replaced frequently over about a week (pt in charge)
- Tricky for patient, must wear tray whole time – wear 24 hours a day
Bit more complicated than internal non-vital bleaching– can be faff for pt; but good results
microabrasion
Removes discolouration limited to the outer layers of enamel
- Combination of erosion (acid) and abrasion (pumice)
- Polishing off outer layers of enamel like giving pt tooth wear
4 indications for microabrasion
- Fluorosis
- Post orthodontic demineralisation
- Demineralisation with staining
- Prior to veneering if dark staining is present
superficial staining only
deeper stains in enamel not suited
technique for microabrasion
- Clean teeth thoroughly
- Rubber dam (seal is very important)
- crucial- HCl = damage gingiva
- Mix 18% HCl and pumice
- Apply to teeth
- Gently rub with prophy cup 5 seconds/tooth
- Wash
- Repeat up to 10X
- Remove rubber dam
- Polish teeth with fluoride prophy paste
- apply F gel or varnish
- Fluoride to help reharden the surface and decrease sensitivity
- Review after one month
- Can be hard to tell success as teeth can appear frosty due to acid used
Can be repeated – cannot be used too often as removing enamel
issues in many repetitions of microabrasion
- Too much can lead to yellowing of the tooth as the dentine begins to show through
- Too much will lead to permanent sensitivity
why polish teeth with F prophy paste after microabrasion
as softened teeth with HCl
concentration of HCl used in microabraion and time
18% HCl and pumice
- Apply to teeth
- Gently rub with prophy cup 5 seconds/tooth
advantages of microabrasion (3)
- Quick
- Easy
- No long-term problems
- Pulpal damage
- caries
4 disadvantages of microabrasion
- Acid
- Sensitivity
- Only works for superficial staining
- Works much better for brown staining than white marks
alternative to 18% HCl for use in microabrasion
37% phosphoric acid rather than HCl
- HCl removes 100microns
- Phosphoric acid only removes 10microns (10% of HCl)
Etch first with phosphoric acid and for longer (30s) prior to using pumice.
- Takes longer
Not as effective but this acid is readily available to GDP
resin infiltration used to treat tooth discolouration of
white stains
resin infiltration in tooth discolouration tx
Don’t remove the surface layer
- Infiltrate the white area with resin (more porous enamel)
- Changes the refractive index of the white area
- Masks it and makes it look like the surrounding enamel
Marketed initially as a method of treating early caries by resin infiltration
- Used for treatment of white spot lesions
- Hyrdophilic resin impregnation of the porous enamel surface in white area
pro and con of resin infiltration
Resin infiltration appears to demonstrate an immediate masking effect
BUT
- The durability of esthetic results requires longer term study
- due to potential staining
- Aging of the low viscosity resins used
- Resin – long term benefits unclear currently*
- Can be good as adjunct as non-invasive management*
UK vs USA view on tooth bleaching products
UK tooth bleaching products are considered a cosmetic as opposed to the USA (and most of the rest of the world) where they are a medical device.
law in regards tooth whitening UK
The Cosmetic Products (Safety Amendment) Regulations 2012 (implementing Directive 2011/84 EU which amends directive 76/768/EEC) came into force in October 2012
what must be carried out prior to any tooth whitening procedures
pt must be deemed dentally fit
An appropriate Clinical Examination is carried out
- Free of Dental Pathology – caries, cavities, perio, apical etc
- Medical contraindications
- Very rare
- Glucose-6-Phosphate dehydrogenase deficiency
- Acatalasemia
- Neither group can metabolise hydrogen peroxide
2 medcial conditions that cannot metabolise hydrogen peroxide
therefore risk in tooth bleaching
- Glucose-6-Phosphate dehydrogenase deficiency
- Acatalasemia
max concentration of H2O2 in tooth whitening produts
6% for cosmetic purposes
who cannot have products containing 0.1-6% H2O2
cannot be used on any person under 18 years of age
- except where such use is intended wholly for the purpose of preventing disease.
- E.g. mental health benefit due to discoloration central incisor
what level of H2O2 is safe and can be sold on market
Products containing, 0.1% hydrogen peroxide, including mouth rinse, toothpaste and tooth whitening or bleaching products
range of H2O2 % which should not be available to public to buy
0.1%-6% hydrogen peroxide should not be made directly available to the consumer, other than through treatment by a registered dentist (or dental hygienist or dental therapist or clinical dental technicians working to a dentist’s prescription).
- Breach of these regulations is a criminal offence.
- This is enforced through trading standards
tooth whitening/bleaching products 0.1-6% H2O2
used how
Exposure to these products should be limited to ensure that the products are only used in terms of frequency and duration of application
- The products should not be directly available to the consumer
- only through a dentist, hygienist, therapist or clinical dental technician
Whitening products can only be sold by dental practitioners
- The first cycle of treatment must be supervised
- After the first cycle the product may be provided for use by the consumer
Concentrations exceeding 6% hydrogen peroxide remain prohibited, unless wholly for the purpose or prevention of disease.
It is a criminal offence to breach these guidelines
what will happen if supply products in excess of 6% H2O2
Dentists supplying bleaching products if in excess of 6% will be prosecuted by Trading Standards.
If a dental professional is found to be using a product in excess of 6% for cosmetic purposes, they will face fitness to practice proceedings (after prosecuted by Trading Standards)
- Non registrants providing tooth whitening will be prosecuted by the GDC under the Dentists Act 1984 for illegal practice of dentistry
