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