Intrinsic Discolouration

Question 1

What are the treatment options for intrinsic discolouration?

Answer 1

Enamel Microabrasion
Bleaching (vital/non-vital)
Resin infiltration technique (ICON)
Localised composite restoration
Veneers

Question 2

What is the technique steps for HCL pumice?

Answer 2

PPE
Patient must be wearing bib and glasses
Clean teeth with pumice and water
-in slow rotating rubber cup (wash into aspirator)
-max 10 x 5 second applications
Petroleum Jelly to gingivae
Rubber dam must be placed
Place sodium bicarbonate guard

Question 3

What are the advantages of microabrasion?

Answer 3

Easily performed
Conservative
Inexpensive
Teeth need minimal subsequent maintenance
Fast acting
Removed yellow-brown, white and multi-coloured stains
Effective
Results are permanent
Can use before or after bleaching

Question 4

What are the disadvantages of microabrasion?

Answer 4

Removes enamel
HCL acid compounds are caustic
Requires protective apparatus for patient, dentist and nurse
Prediction of treatment outcome is difficult
Must be done in dental surgery

Question 5

What solution is used in nightguard vital bleaching?

Answer 5

10% carbamide peroxide gel

Question 6

What instructions do you give the patient for nightguard vital bleaching?

Answer 6

Brush teeth thoroughly
Apply a little gel to tray
Set over teeth and press down
Remove excess
Rinse gently, do not swallow
Wear overnight, or for at least 2 hours
Remove tray and brush and rinse with cold water

Question 7

What is in carbamide peroxide?

Answer 7

3% hydrogen peroxide
7% urea
Catalyse together and peroxidases to turn into water, ammonia and carbon dioxide

Question 8

What are the vital bleaching options? (external vital bleaching)

Answer 8

Chairside
Night guard at home

Question 9

What are the non-vital bleaching options? (internal non-vital bleaching)

Answer 9

Inside out technique
Walking bleach technique

Question 10

What is involved in tooth selection for non-vital bleaching?

Answer 10

Adequate root filling
-no clinical or radiological disease
Anterior teeth without large restorations
Not amalgam intrinsic discolouration
Not fluorosis or tetracycline discolouration

Question 11

What is the walking bleach technique?

Answer 11

Oxidising process allowed to proceed gradually over days
Bleach is renewed within 2 weeks of applying internally
If no change after 3-4 renewal the process is stopped

Question 12

What is ‘inside-out’ bleaching?

Answer 12

Access cavity of tooth
Custom made mouthguard (cut windows in teeth you do not want to bleach)
Patient applied bleaching agent to back of tooth and tray
Patient keeps access cavity clean, replacing gel, cleaning food debris etc
Worn all the time except eating and cleaning
Gel changed every 2 hours except for overnight

Question 13

How would you restore the pulp chamber after internal bleaching?

Answer 13

Non setting calcium hydroxide paste for 2 weeks, seal in with GIC
Either
-White GP and composite resin- can rebleach
-Incrementally cured composite - no re-bleaching but stronger
Veneer or crown prep if regression

Question 14

What are the potential complications that can occur after bleaching?

Answer 14

External cervical resorption
Spillage of bleaching agents
Failure to bleach
Over bleach
Brittleness of tooth crown

Question 15

How can you prevent external cervical resorption?

Answer 15

Layer of cement over GP
–prevents bleaching agent from getting to external root surface
–can prevent adequate bleaching of the cervical area
Non-setting calcium hydroxide in tooth 2 weeks before final restoration
–reverses any acidity in PL that might have occurred

Question 16

What is resin infiltration?

Answer 16

Infiltration of enamel lesions with low-viscosity light-curing resins
Surface is eroded, lesions desiccated and a resin infiltrant is applied
Resin penetrates lesion driven by capillary forces
Infiltrated lesions lose their discoloured appearance and look similar to sound enamel