Tooth Whitening Flashcards
what are types of tooth discolouration? (2)
extrinsic
intrinsic
what causes extrinsic discolouration? (6)
- Smoking: most common
- Tea and coffee (tannins)
- Red wine and Guinness (tannins)
- Chromogenic bacteria: common in children
- Chlorhexidine
- Iron supplements
what causes intrinsic discolouration? (9)
- Fluorosis: depends on which area in the world you’re in.
- Tetracycline: bands of colouration (not common these days, seen in wisdom teeth of teenagers on this medication for acne)
- Non-vitality
- Physiological
- Dental materials: amalgam
- Porphyria = red primary teeth
- CF = grey
- Thalassaemia and sickle cell = blue, green, brown
- Hyperbilirubinemia = green teeth
what is the first stage in carrying out extrinsic whitening?
hygiene phase therapy
what types of bleaching can we use? (2)
External bleaching
Intrinsic bleaching
what does bleaching teeth do?
External discolouration of teeth is caused by the formation of stable chromogenic produces within the tooth
To combat this;
We bleach the teeth to oxidise these compounds and break them up to form smaller molecules which are not as pigmented.
what is the active agent in bleaching products?
Hydrogen peroxide
what is the oxidising agent in bleaching products?
the free radical per hydroxyl produced from hydrogen peroxide
what kind of gel do we use in bleaching?
Carbamide peroxide – this breaks down to produce hydrogen peroxide (active component) and urea
what percentage of hydrogen peroxide is in 10% carbamide peroxide?
3.6%
what is the maximum amount of hydrogen peroxide we can use in bleaching?
6%
so 16.7% carbamide peroxide
What is the role of the Carbopol in the bleaching gel? (2)
- It is used to thicken the gel so that it stays on the teeth and in the trays.
- It also allows slow diffusion into the enamel
What is the role of the urea in the bleaching gel? (2)
- It is used to raise the pH (counteract the acidity)
- stabilise the hydrogen peroxide
What is the role of the potassium nitrate and calcium phosphate in the bleaching gel? (1)
- They are used as tooth desensitising agents
What is the role of fluoride in the bleaching gel? (2)
- It is used as tooth desensitising agent
- Used to prevent erosion
What factors influence the successful outcome of bleaching? (4)
- Time = the longer the better
- Cleanliness of the tooth surface
- Concentration = higher
- Temperature = higher
what steps must we take before initiating external bleaching? (3)
- Have to ensure that restoration margins are intact to protect the pulp
- Shade match with the patients input – record in the notes
- Also good practice to take a clinical photograph along with the shade match
what risks should we inform the patient of before bleaching? (6)
- Sensitivity (temporary)
- Relapse
- Restoration colour doesn’t change like the teeth
- Allergy
- Poor success
- They have to comply with the regime
where can external bleaching be carried out? (2)
Chair side/in-office
Home
what are the advantages of carrying out external bleaching in office? (2)
- Controlled by a trained professional
- Can use heat/light to increase the success and speed up the process = quick
what are the disadvantages of carrying out external bleaching in office? (3)
- Can be uncomfortable
- Wears off quicker
- Expensive
what concentration of carbamide peroxide gel are patients given to use at home?
10-15%
what kind of splint is made for home external bleaching?
A custom made thick, soft, acrylic vacuum formed splint with a buccal spacer – 1mm short of the gingival margin
what must the patient have before carrying out home external bleaching? (2)
Patient must have full mouth scaling/polishing in surgery beforehand
Check the fit of the tray
what are the instructions for use of home external bleaching? (3)
- Brush and floss first
- Load the tray with a 1mm2 dot on the buccal surface of each tooth
- Wear for at least 2 hours or overnight
when after home bleaching will the patient see results?
2-3 days
when are the MAXIMUM home bleaching results seen?
3-4 weeks
what are the indications for external bleaching? (4)
- In age related discolouration
- In mild fluorosis
- Post smoking cessation
- In tetracycline staining
what are the risks of external bleaching? (5)
- Sensitivity
- Cytotoxicity: only when using high concentrations of hydrogen peroxide
- Gingival irritation: when the tray extends into the gingivae
- Tooth & restoration damage: composite doesn’t bleach
- Problems with bonding to the tooth: only initially where there is residual oxygen from the peroxide, delay the restoration for a week or so.
how long after external bleaching does sensitivity resolve?
2/3 days
who is predisposed to sensitivity after external bleaching? (3)
- Pre-existing sensitivity
- High concentration of bleach
- Gingival recession
what bleaching product do we never use and why?
Never use chlorine dioxide it softens the tooth surface = re-staining, roughening and extreme sensitivity
what are the indicators for use of internal bleaching? (3)
- Non vital teeth
- Teeth with adequate RCT
- Teeth with no apical pathology
what causes non-vital discolouration?
- Dead pulp which bleeds into the dentine tubules and darkens the tooth
- Grey teeth
what are the contraindicators to internal bleaching? (2)
- Heavily restored teeth
- Staining due to amalgam
what are the advantages of internal bleaching? (3)
- Easy
- Conservative
- Patients are satisfied
what are the risks associated with internal bleaching? (1)
- External cervical resorption: more of a theoretical risk
The hydrogen peroxide diffuses through the dentine and into the periodontal tissues. (occurs more in teeth with trauma and very high concentrations)
when are the results of internal bleaching seen?
after 3/4 visits
what is the problem with inside - outside bleaching?
bleaching tray must be worn constantly = poor patient compliance
what are alternative to bleaching? (2)
micro-abrasion
resin infiltration
describe how microabrasion works.
Removes discolouration from the outer layers of enamel using a combination of erosion and abrasion
what discolouration responds better to microabrasion?
brown
what are the indicators for use of micro-abrasion? (4)
- Fluorosis
- Post orthodontic demineralisation
- Demineralisation with staining
- Prior to veneering if there are dark stains present
what are the advantages of micro-abrasion? (3)
- Quick
- Easy
- No long term problems (if you don’t strip too many layers of enamel off the teeth)
what are the disadvantages of micro-abrasion? (2)
- Sensitivity
- Only useful in superficial staining
what can happen if micro-abrasion is done too often?
yellowing of the teeth from the dentine showing
what acid is better to use phosphoric of hydrochloric?
phosphoric acid only takes away 10% of what hydrochloric acid does.
(most practices won’t have hydrochloric acid present)
For what type of discolouration is resin infiltration used?
white stains
describe how resin infiltration works.
Not removing the surface layer we are infiltrating the porous surface enamel and restoring it’s natural tooth colour
what material do we use in resin infiltrations?
ICON
what age must you be for tooth whitening? what are the exceptions?
You must be 18 years of age
unless used in preventing disease
e.g. internal bleaching can be used after paediatric trauma in order to prevent difficulties with appearance and mental health in later life.
what are medical contraindicators to tooth whitening? (2)
- Glucose 6 phosphate dehydrogenase deficiency
- Acatalasemia
conditions where you cannot metabolise hydrogen peroxide
what are the (2) legal guidelines for use of whitening products?
- The first cycle of treatment must be supervised by the trained professional
- The following cycles can be carried out by the consumer with the professionals providing the product.
