1 - Discolouration Flashcards

1
Q

What are the broad treatment options for discolouration?

A
  • enamel microabrasion
  • bleaching
  • resin infiltration
  • localised composite restoration
  • veneers
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2
Q

What pre-op records are required for discoloured teeth?

A
  • clinical photos
  • shade
  • sensibility testing
  • can also take radiographs, defect diagram, patient self-assessment
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3
Q

Describe the HCl pumice microabrasion technique.

A
  • vaseline to gingivae, rubber dam placed and sodium bicarbonate guard
  • HCl pumice slurry in slowly rotating rubber cup for 10s x 5 on each tooth
  • wash tooth into aspirator between each pumice
  • polish with sandpaper disc
  • apply fluoride varnish
  • polish with toothpaste
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4
Q

What fluoride varnish is recommended for HCl pumice microabrasion?

A
  • profluorid
  • duraphat is yellow in colour and can stain teeth
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5
Q

What concentration of HCl is used for microabrasion?

A

18%

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6
Q

What is the purpose of the sodium bicarbonate guard?

A

To neutralise the acid and prevent damage to the rubber dam and injury to the patient

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7
Q

What is the purpose of polishing with sandpaper discs?

A
  • changes the optical properties of the enamel prisms
  • areas of intrinsic discolouration become less perceptible
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8
Q

How much enamel is removed using microabrasion?

A

100 microns

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9
Q

What are the advantages of microabrasion?

A
  • conservative
  • inexpensive
  • minimal maintenance
  • fast acting
  • removes yellow/brown/white stains
  • effective
  • results are permanent
  • can be used alongside bleaching
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10
Q

What are the disadvantages of microabrasion?

A
  • removes enamel
  • HCl is caustic
  • requires PPE
  • prediction of outcome is difficult
  • must be done chair side
  • cannot be delegated
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11
Q

What POI are important after microabrasion?

A
  • avoid highly coloured food and drink for 24-48 hours
  • “anything that would stain a white t-shirt”
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12
Q

When should you review a microabrasion treatment?

A
  • 4-6 weeks with post-op photos
  • teeth are dehydrated after procedure so final result may differ
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13
Q

What is the legislation surrounding bleaching in children?

A

Bleaching with hydrogen peroxide is not allowed in U18s except for the use which is wholly intended for the purpose of treating or preventing disease

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14
Q

What are the different types of bleaching?

A
  • vital bleaching
  • non-vital bleaching
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15
Q

What are the different types of vital bleaching?

A
  • power bleaching (chairside)
  • night guard bleaching
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16
Q

What are the different types of non-vital bleaching?

A
  • inside outside technique
  • walking bleach technique
17
Q

What chemical is used for chairside power bleaching?

A

Fast acting 15-38% hydrogen peroxide

18
Q

What chemical is used for night guard bleaching?

A

10% carbamide peroxide

19
Q

How long does night guard bleaching take to get a desired result?

A

3-6 weeks

20
Q

What is the breakdown of carbamide peroxide?

A
  • 10% carbamide peroxide
  • 3% hydrogen peroxide, 7% urea
  • water, ammonia and CO2
21
Q

What are the advantages of non-vital bleaching?

A
  • conservative
  • original tooth morphology
  • gingival tissues are not irritated by a restoration
  • adolescent gingival margin is not a restorative consideration
  • no laboratory involvement
22
Q

What is the selection criteria for non-vital bleaching?

A
  • adequate root filing with no clinical or radiographic disease
  • anterior tooth without large restoration
  • no amalgam intrinsic discolouration
  • discolouration is not due to fluorosis or tetracycline
23
Q

Describe the preparation for “walking” non-vital bleaching.

A
  • GP removed below gingival margin
  • cotton wool pellet soaked with bleaching agent placed in cavity
  • dry cotton wool pellet to cover
  • sealed with GIC
24
Q

What is the frequency of appointments for walking bleach?

A
  • renew bleach every 2 weeks
  • 6-10 changes total
25
Q

Describe the preparation for combination non-vital bleaching.

A
  • access cavity
  • remove GP below gingival margin
  • GI lining
  • custom made trays given to patient and bleaching agent
26
Q

What instructions should be given to patients using combination non-vital bleaching?

A
  • ensure cavity is kept clean
  • apply bleaching agent to back of tooth and in tray
  • gel changed every 2 hours except during night
  • to wear trays at all times except eating and cleaning
27
Q

Describe the restoration of the pulp chamber after non-vital bleaching.

A
  • non-setting CaOH for 2 weeks to reverse acidity of chamber
  • either, white GP and composite (facilitate re-bleach)
  • or, incrementally cured composite (no re-bleach)
28
Q

What are the potential complications of non-vital bleaching?

A
  • external cervical resorption (more common in traumatised teeth)
  • spillage of bleaching agents
  • failure to bleach
  • over bleach
  • brittle crown
29
Q

What is the indication for tooth mousse after bleaching?

A
  • sensitivity
  • prevention
30
Q

What contraindicates the use of tooth mousse?

A
  • dairy allergy
  • religious views
31
Q

Describe the process of resin infiltration.

A
  • surface eroded
  • lesions desiccated
  • resin infiltrant applied
32
Q

What causes the resin to infiltrate the enamel?

A

Capillary forces due to the lesion being desiccated

33
Q

What causes the change in discolouration using resin infiltration?

A

Resin changes refractive index of enamel

34
Q

What should you warn patients of before resin infiltration?

A
  • takes away white lesions, to appear more like background enamel
  • can be used in conjunction with bleaching but resin may block enamel prisms and prevent uniform bleach
35
Q

What method of treating discolouration is recommended for tetracycline staining?

A
  • composite veneers
  • will not respond to other methods
36
Q

Why are veneers contraindicated in younger patients?

A
  • gingival margin level does not finalise until early 20s
  • restoration margin may become visible as level finalises