ENDO Bleaching Flashcards
What are the types of tooth discolouration?
Intrinsic Extrinsic
What is intrinsic staining?
Staining that involves the dentine
What is extrinsic staining?
Staining that involvesthe enamel
Describe intrinsic staining?
Staining of the detine from:
Pulpal changes
Iatrogneic
Others (genetic/tetracycline)
Describe extrinsic staining?
Staining of the dental pellicle, caused by smoking, wine, coffee/tea or can be flurosis
What pulpal changes can cause instrinsic staining?
Canal calcification, pulp haemorrhage or necrosis
What iatrogenic changes can cause intrinsic staining?
- Failure to remove all pulp tissue remnants from pulp chamber
- Amalgam
- Certain sealer/cement in the pulp chamber (ledermix, GP)
What are other causes of intrinsic staining?
Tetracycline staining, fluorosis, genetic (AI,DI)
What is combined staining
Both intrinsic and extrinsic staining, caused by:
- Age
- Flurosis
What are common bleaching materials used?
- Sodium Perborate
- Hydrogen Peroxide
- Carbamide Peroxide
What is the chemical formula for sodium perborate?
NaBO3
What is the chemical formula for hydrogen peroxide?
H2O2
What is the chemical formula for carbamide peroxide?
CH6N2O3
What is the safest bleach material out of the 3?
Carbamide peroxide
What is safer hydrogen peroxide or sodium perborate?
sodium perborate
What is the pH of sodium perborate?
10
What happens to sodium perborate when it comes into contact with water?
It reacts with water and breaks down into 10% hydrogen peroxide.
Which bleaching material must you use rubber dam with?
Hydrogen peroxide
What is the conc range of hydrogen peroxide and what is the most commonly used conc?
5-35%
30-35%
How do you manage discoloured teeth.
- Diagnose
- Ask pt to change habits, remove staining foods from diet
- Scale and clean
- Bleaching
- Home bleaching
- In-chair bleaching
- Microabrasion - Veneers
What is the alternative to bleaching ?
Restorative treatments: veneers
What are the disadvantages with restorative tx for discolored teeth?
Biologic cost
Tx only masks the discolouration
How is home bleaching done?
In a custom tray or stick tray, with 10-30% carbamide peroxide
How is power bleaching (in chair bleaching) done?
Using a high concentration 30-35% hydrogen peroxide, with the addition of light to enhance bleaching. More effective than home bleaching
What is microabrasion?
Procedure to remove the superficial discoloured defects from teeth, and fluoride products are introducted to reminerlaise the teeth.
What are the indications for microabrasion?
Mild flurosis
what are the limitations of microabrasion?
Intrinsic discolourations like tetracycline staining, AI, DI
What is the procedure of microabrasion?
Rubber dam, then apply PREMA paste (low conc H2O2 and fine grit) to the tooth surface, with prophy cup for 60s. Then give patient NaF gel to take home and apply. Recall in 4-6 weeks.
What is the chemistry of bleach?
Bleaching teeth is an oxidation reduction reaction, hydrogen peroxide produces highly reactive free radicals, and they move through the dentine tubules to break down chromophores (organic material). This breakdown causes less light to be absorbed and thus the whitening effect.
Can you restore teeth that have been bleached?
Only after 7 days, as it takes this long for the bleach to leech out of the tooth, otherwise it will affect the bond strength
What is the walking bleach procedure?
Placing bleach in the access cavity of an endo treated tooth that has been intrinsically discoloured.
What is the procedure for walking bleach technique?
- Apply rubber dam
- Access tooth
- Acid etch the access cavity for 60s
- Mix sodium perborate and water into a wet sand texutre
- Deliver bleach to access cavity, esp labial wall of pulp chamber
- Temporise: place cavit/GIC into the acces
- Take post op photos
- Recall in 7 days
- Repeat process until desired bleaching effect acheived.
- If happy, place definitive resto (make sure you wait atleast 7 days).
Should you bleach the tooth immediately after obturation?
No, because the cavit and sealer will not have set.
What is the recall for children compared to adults in the walking bleach procedure?
3-5 days in paeds pts compared to 7 days in adult pateints as the dentine tubules are wider and bleach will penetrate more.
What discolouration will trauma usually cause?
Light yellow, grey
What colour discolouration will prev dental tx, pulp necrosis, calcification cause?
Dark yellow
