Tooth Whitening Revision Questions Flashcards
Causes of extrinsic tooth whitening
Smoking CHX Tannins Chromgenic Bacteria Iron supplements
Causes of intrisinc tooth whitening
Fluorisis Non-vitality porphria - red primary teeth cystic fibrosis - grey teeth thalassmia, sickle cell - blue, green, brown teeth
What causes disclouration of teeth
discolouration is caused by the formation of chemcially stable chromogenic products within the tooth substance
long chain organic molecules
bleaching oxidises compounds and leads to smaller molecules not pigmented
Treatment for tooth discolouration
HPT Vital external bleaching Internal non vital bleaching Micro abrasion Resin infiltration
Consitiuents of bleaching gel
Carbamide peroxide - breaks down to produce hydrogen peroxide and urea, urea increases pH
Carbopol - thickening agent that slows release of oxygen, slows diffusion into enamel, increases viscosity of gel
Urea - raises pH and stabilies hydrogen peroxide
Surfactant - allows gel to wet tooth surface
Fluoride - prevents erosion and desenstitsing effect
Potassium, nitrate, calcium phosphate - tooth densensitising agents
What is home bleaching
10-15% carbamide peroxide gel with custom made trays
results within 2-3days and max by 3-4weeks
What is resin infiltration
Don’t remove the surface layer but infiltrate white area with resin
Changes refractive index of white area
What is micro-abrasion
Removes discoloration on outer layers of enamel
Combination of erosion (acid) and abrasion (pumice)
37% phosphoric acid
What are indications for microabrasion
Flurosis
Post ortho demineralisation
Demineralisation with staining
Indications for internal non vital bleaching
Non vital tooth
Adequate RCT
No apical path
What are contraindications of internal non vital bleaching?
Heavy resotred teeth/staining due to amaglam
What factors affect bleaching
time cleanliness of tooth surface Conc of solution Temp Ensure patient is dentally fit
What factors lead to sens
Conc of H2O2
Previous sens
Ging recession
What are some bleaching problems
sens - resolves over 2-3days post bleaching
wears off - retreatment 1-3 years
cytotoxicity/matageriaty - hogh con H2O2 can cause problems
Ging irriatation - much check extension correct
Problems with bonding - residual oxygen from peroxide remains within enamel structure intitally
Tooth damage
Damage to restorations - teeth bleach but composite does not
