Tooth Whitening Flashcards
List some extrinsic causes of tooth discolouration (5)
- Smoking
- Tannins
- Tea
- Coffee
- Red wine
- Guinness - Chromogenic bacteria
- Common in children - Chlorrhexidine
- Iron supplements
List some intrinsic causes of tooth discolouration (7)
- Fluorosis
- Tetracycline
- Non vitality
- Blood products
- Tooth dies becomes darker over time as pulp dies and products leach into dentine - Physiological
- Age changes - Dental materials
- Amalgam
- Root filling materials - Porphyria
- Red primary teeth - Cystic fibrosis
- Grey teeth
Whats the 1st method of tooth whitening for extrinsic staining?
HPT
- scaling etc
What are the 2 types of tooth bleaching?
- External vital bleaching
2. Internal non-vital bleaching
When is external vital bleaching used? (2)
- Discolouration forms chemically stable, chromogenic products within the tooth surface
- Bleaching oxidises these compounds and leads to smaller molecules that are not pigmented
Active ingredient for vital external bleaching
Hydrogen peroxide
- Forms an acidic solution in water
- Breaks down to form water + o2
- Free radical per hydroxyl (HO2) is formed (the active oxidising agent)
What are the constituents of bleaching gel? (9)
- Carbamide peroxide
- Carbopol
- Urea
- Surfactant
- Pigment dispersers
- Preservative
- Potassium nitrate
- Calcium phosphate
- Fluoride
What does carbamide peroxide break down to produce?
Hydrogen peroxide + urea
Function of carbopol (3)
- Thickening agent
- Slows the release of o2 and diffusion into enamel
- Increases viscosity of gel so it stays where you put it
- Teeth
- Tray
Function of urea (2)
- Raises pH
- Stabilises Hydrogen peroxide
- Slows down the reaction
Function of surfactant
Allows gel to wet the tooth surface
Function of potassium nitrate/calcium phosphate
Desensitising agent
Function of fluoride
Prevents erosion
Desensitising agent
List factors that affect bleaching (4)
- Time
More time = more effect - Cleanliness of tooth surface
Cleaner = better - Concentration of solution
Higher conc = more+quicker effect - Temperature
Higher = quicker effect
What must you check before starting bleaching?
Patient is dentally fit
Any leakage around carious cavity margins will lead to pulpal damage
- Take an initial shade
- Agree with patient + record in their notes
- Take a phoot with shade guide included in the picutre
Warnings for patient about external vital bleaching (6)
- Sensitivity
- Relapse
- Restoration colour
- Allergy
- Might not work
- Compliance with regime
What are the 2 types of vital external bleaching we can offer?
- Chairside
2. Home bleaching
Advantages of in office bleaching (3)
- Controlled by dentist
- Can use heat/light
- Quick results for patient
Disadvantages of in office bleaching (4)
- Time for dentist
- Can be uncomfortable
- Results tend to wear off quicker
- Expensive
Talk through the in-office bleaching technique (6)
- Thorough cleaning of teeth
- Ideally rubber dam, but atleast gingival mask
- Apply bleaching gel to tooth
- Apply heat/light
- Wash/dry repeat
- Takes 30 mins to an hour
Talk through the home vital bleaching technique (4)
- 10-15% carbamide peroxide gel
- Patient uses solution at home with a custom made mouthguard tray
- Bleaches slowly, over several weeks
- Easy for dentist + patient
What doest 16.7% carbamide peroxide equate to?
6% of hydrogen peroxide = max strength of solution
Anything stronger = illegal