PRS02 - Lecture 1 - Discoloured Teeth Flashcards
What are the 2 main causes of discoloured teeth?
Extrinsic
Food + drink -> tannins
Smoking
Chromogenic Bacteria
Intrinsic
Local
Generalised
GIve examples of local and generalised instrinsic factors that cause tooth discolouration
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
What should be done prior to treating discolouration? (4)
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.
What are the 4 different methods of treating discolouration?
No treatment (if consented by patient)
Bleaching -> internal, external, microabrasion
Veneers -> direct composites, indirect porcelain or composites.
Crowns -> all ceramic, full metal, metal ceramic.
Describe Microabrasion (3)
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.
Describe Internal Bleaching (10)
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.
Describe External Bleaching (7)
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.
How can External Bleaching be done chairside?
Using light-activated 35% hydrogen peroxide -> ↓ Visits + ↑ Speed of results.
How many shades can a patient go up in from bleaching?
3
What are the disadvatanges of bleaching? (6)
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
What are Veneers?
Thin covering of restorative material placed on -> labial surface of an anterior tooth.
What are Veneers used for? (3)
Improve shape or colour
Close diastemas (gaps)
Mask enamel hypoplasia
What do Veneers require to be placed? (2)
Healthy sound enamel
It derives its strength from its bond to enamel and underlying tooth structure
What are the 2 types of veneers?
Direct composite
Indirect (porcelain or composite)
What are Direct composite veneers?
When you place layers of different shades of composites to match enamel and dentine.
What are the advantages and disadvantages of direct composite veneers? (5:6)
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
Describe Indirect Veneers (4)
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).
What are the advantages and disadvantages of Indirect Veneers? (4:8)
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
Whats the main differences between indirect composite and porcelain veneers? (2:4)
Composite (2)
Easy to adjust
↑ Staining
Porcelain (4)
↑ Aesthetics
↓ Staining
Brittle
Difficult to repair
What is a crown?
A cap that completely covers the tooth
What are the indications for crowns? (7)
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
What are the 3 types of crown?
Full gold crown
Metal-ceramic crown
All ceramic crown
When should crowns be used to treat discolouration?
When all other (least invasive) methods have failed
