PRS02 - Lecture 1 - Discoloured Teeth Flashcards

1
Q

What are the 2 main causes of discoloured teeth?

A

Extrinsic

Food + drink -> tannins

Smoking

Chromogenic Bacteria

Intrinsic

Local

Generalised

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2
Q

GIve examples of local and generalised instrinsic factors that cause tooth discolouration

A

Local

Trauma (pulp death – RBCs release haemoglobin where iron stains the dentine.

Caries – CREBS reaction -> discolouratio

Toothwear – dentine is yellow

Generalised – occur during development of the tooth

Fluorosis

Tetracycline staining (antibiotics induced)

Amelogenesis/dentinogenesis imperfecta

Illness

Trauma (pulp death)

Caries

Toothwear

Aging

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3
Q

What should be done prior to treating discolouration? (4)

A

Treat any disease or lesions present

Make patient aware that any existing restorations will not change colour thus may need to be done again.

Scale and polish should be done -> remove calculus and superficial staining

OHI and dietary advice should be offered to prevent further staining.

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4
Q

What are the 4 different methods of treating discolouration?

A

No treatment (if consented by patient)

Bleaching -> internal, external, microabrasion

Veneers -> direct composites, indirect porcelain or composites.

Crowns -> all ceramic, full metal, metal ceramic.

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5
Q

Describe Microabrasion (3)

A

Used for superficial enamel discolouration (i.e. enamel fluorosis, white/brown spots not caries induced, opacities).

Rub cream containing HCl (18%) + silicon carbide micro-particles (abrasive).

Least invasive technique -> cannot be used for deep stains.

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6
Q

Describe Internal Bleaching (10)

A

Used for non-vital teeth where the pulp contents have gone into the dentine and caused the discolouration (i.e. caries, trauma, toothwear)

1) Tooth has to be RCT treated with a good seal and restoration.

2) Take a shade and intra-oral digital photograph.

3) Rubber dam applied

4) Re-access the pump chamber

5) Remove 2-3mm apical to the CEJ (If you don’t remove enough GP – then only top half of the crown will bleach)

6) Apply a good seal (i.e. GIC) – to prevent leaching and cervical resorption.

7) Syringe hydrogen peroxide + sodium perborate or carbamide peroxide -> chamber

8) Place cotton wool pellet + seal with temporary cement (i.e. ZOE/GIC).

9) Recall after 2 weeks – and repeat until desired shade is reached -> place definitive restoration.

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7
Q

Describe External Bleaching (7)

A

Used for vital teeth where there is generalised discolouration (i.e. aging, fluorosis, illness, tetracycline staining).

1) Patient need to be over 18, dentally fit and competent -> as they are doing it at home.

2) Impression is taken to construct -> close fitting bleaching tray

3) It is 1mm soft vacuum formed silicone material – which is trimmed in the gingiva area -> only in contact with teeth.

4) Dispense carbamide peroxide (10-15%) into the bleaching tray (<pea></pea>

5) Leave over-night or during the day -> atleast 4 hours (not too long -> ↑ sensitivity)

6) Review in 2 weeks.

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8
Q

How can External Bleaching be done chairside?

A

Using light-activated 35% hydrogen peroxide -> ↓ Visits + ↑ Speed of results.

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9
Q

How many shades can a patient go up in from bleaching?

A

3

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10
Q

What are the disadvatanges of bleaching? (6)

A

Sensitivty

Re-staining

Lasts ~6 months

Legally active ingredient of hydrogen peroxide (6% or less)

Doesn’t work on discolouration thats too dark

Post-pone resotrative treatment 2-4 weeks after bleaching -> wont reach optimum shade + oxygen free radicals in dentine ↓ bond strength of composites

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11
Q

What are Veneers?

A

Thin covering of restorative material placed on -> labial surface of an anterior tooth.

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12
Q

What are Veneers used for? (3)

A

Improve shape or colour

Close diastemas (gaps)

Mask enamel hypoplasia

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13
Q

What do Veneers require to be placed? (2)

A

Healthy sound enamel

It derives its strength from its bond to enamel and underlying tooth structure

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14
Q

What are the 2 types of veneers?

A

Direct composite

Indirect (porcelain or composite)

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15
Q

What are Direct composite veneers?

A

When you place layers of different shades of composites to match enamel and dentine.

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16
Q

What are the advantages and disadvantages of direct composite veneers? (5:6)

A

Advantages (5)

No preparation necessary

Preserves tooth structure

Doesn’t involve lab (↓ cost and done in single session)

Easy to repair

Can incorporate existing composites.

Disadvantages (6)

Technique sensitive (requires good bonding, marginal adaptation, moisture control)

↑ initial chairside time

Additional technique – so cannot change teeth that require reduction

Bulky teeth + can change occlusion

Staining

Weak -> prone to chipping

17
Q

Describe Indirect Veneers (4)

A

1) Made from either porcelain (feldspathic 0.5-0.6mm or lithium disilicate 0.3mm) or composite -> in the lab

2) Tooth preparation:

Stays within the enamel

0.3-0.5mm reduction on labial surface

Finish at gingival margin

Approximal reduction should not go through contact point.

Check occlusion.

3) Impression is taken and sent to -> lab and provisional veneer placed.

4) Definitive veneer is bonded to tooth using resin based cement (i.e. Panavia, Nexus, Calibre).

18
Q

What are the advantages and disadvantages of Indirect Veneers? (4:8)

A

Advantages (4)

↓ Chairside time

↓ Staining (porcelain resistant to staining)

Good marginal adaptation

Anatomy easier to control (as its carried out by technician)

  • *Disadvantages** (8)
  • *↑ invasive**

↑ lab costs

Composite resin cement -> weak.

Difficult to repair and maintain

Multiple visits are required

Shade matching difficult

Temporisation difficult (temporary veneer can’t be bonded to tooth)

Cementation technique sensitive

19
Q

Whats the main differences between indirect composite and porcelain veneers? (2:4)

A

Composite (2)

Easy to adjust

↑ Staining

Porcelain (4)

↑ Aesthetics

↓ Staining

Brittle

Difficult to repair

20
Q

What is a crown?

A

A cap that completely covers the tooth

21
Q

What are the indications for crowns? (7)

A

Severely broken down tooth

Root filled tooth (↑ prognosis)

Support bridges and partial denture (abutments)

Tooth wear

Change appearance (i.e. discoloration)

Change occlusion

Hypoplastic conditions

22
Q

What are the 3 types of crown?

A

Full gold crown

Metal-ceramic crown

All ceramic crown

23
Q

When should crowns be used to treat discolouration?

A

When all other (least invasive) methods have failed