Tooth whitening

Question 1

What does hydrogen peroxide break down into?

Answer 1

Water and oxygen that penetrates the tooth and pigment molecule causing the tooth to whiten

Question 2

What does carbamide peroxide break down into?

Answer 2

Hydrogen peroxide and urea

Question 3

What are the risks/side effects of bleaching?

Answer 3

Sensitivity (18-78%)
Relapse
Gingival irritation 
Restorations don’t change colour 
Allergies to preservatives 
Might not work 
Compliance is key

Question 4

What are causes of extrinsic staining?

Answer 4

Tobacco
Food residue - white/yellow
Chromogenic bacteria - green caries; black good OH
Tannins (coffee, tea, red wine) - brown/black
Medications (iron supplements, CHX) - brown/black

Question 5

What are causes of intrinsic staining?

Answer 5

Trauma 
Tetracycline use (yellow/white banding)
Fluorosis (white spots) 
amelogenesis/dentinogenesis imperfecta 
MIH, hypoplasia 
Porphyria (red)
Cystic fibrosis (grey)
Hyperbilorubinaemia (green)
Minocycline (blue teeth and sclera) 
Dental materials - amalgam

Question 6

What are the contraindications for whitening?

Answer 6

Pt receiving chemo, radiation or photosensitive drugs
Pregnant/breast feeding
Pts under 18yrs
Allergies
Heavy smoking habit
Large amount of gingival recession
Poor enamel quality/thickness - erosion cases

Question 7

What percentage of bleaching agent can be sold over the counter?

Answer 7

<0.1% hydrogen peroxide

Question 8

What are the risks of internal bleaching?

Answer 8

External cervical resorption due to diffusion of hydrogen peroxide through dentine into periodontal tissues

Question 9

What strengths of bleaching agents can be used by dentists or on prescription of dentists?

Answer 9

6% hydrogen peroxide

16% carbamide peroxide