Lecture 1 - Discolouration

Question 1

what are general tx options for tooth discolouration?

Answer 1

• enamel microabrasion
• bleaching (vital & non vital)
• resin infiltration technique (ICON)
• localised composite restoration
• veneers

Question 2

what does enamel microabrasion entail?

Answer 2

HCl (hydrochloric acid) & pumice in slowly rotating robber cup, using dental dam

apply some fluoride varnish afterwards

Question 3

what are advantages of microabrasion?

Answer 3

• easy, conversative, cheap, fast, removes yellow/brown/white stains, effective,

Question 4

what are disadvantages of microabrasion?

Answer 4

removes enamel, HCl can burn tissues, must be done in practice, may not work

Question 5

how do we review the effectiveness of microabrasion & what happens straight after the procedure?

Answer 5

teeth are DEHYDRATED straight after so the shade isnt the same.

warn pt to avoid staining agents for ~24 hours

Question 6

what options are there for bleaching permanent teeth in children?

Answer 6

vital bleaching (external):
- chairside
- night guard

Non-vital (dead tooth) bleaching

bleaching effects arent permanent

Question 7

what conc of hydrogen peroxide (and carbamide peroxide) is used for chairside vital bleaching?

Answer 7

Hydrogen peroxide 15-38%

(Carbamide peroxide equivalent = 75%)

Question 8

what % carbamide peroxide is used in nightguard vital bleaching and approx how long is tx carried out for?

Answer 8

10%

3-6 weeks approx, keep going until acceptable colour

Question 9

what is the reaction of carbamide peroxide? how much converts into hydrogen peroxide & urea?

Answer 9

10% CP -> 3% HP + 7% U

Question 10

what are advantages of non-vital bleaching?

Answer 10

simple
tooth conserving
gingival tissues not irritated

Question 11

what are the criteria for teeth that can undergo non-vital bleaching?

Answer 11

• adequate RCT (no clinical or radiological disease)
• anterior teeth without large restorations
• not amalgam intrinsic staining
• not fluorosis or tetracycline discolouration

Question 12

what are the 2 main non-vital bleaching methods called?

Answer 12

• walking bleach
• ‘inside out’ method

Question 13

what is the walking bleach method for non-vital bleaching?

Answer 13

oxidising process allowed to proceed gradually over days

Question 14

what is ‘inside-out’ method for non-vital bleaching?

Answer 14

10% carbamide peroxide gel, can seal in pulp if co-op is an issue

Question 15

what is walking bleach method for non-vital bleaching?

Answer 15

bleaching agent on cotton wool which is placed into pulp chamber and sealed with GI

Renew bleach on cotton wool ~2 weeks, 6-10 changes (12-20 weeks)

Question 16

what is ‘inside-out’ bleaching?

Answer 16

• access cavity created for tooth
• custom mouthguard provided excluding teeth that arent to be bleached
• similar to walking bleach method, bleach also placed in pulp chamber

Question 17

potential complications of non-vital bleaching?

Answer 17

• external cervical resorption
• spillage of bleaching agents
• failure to bleach
• over bleach
• brittleness of tooth crown

Question 18

how can you prevent external cervical resorption when doing non-vital bleaching?

Answer 18

LAYER OF CEMENT OVER GP, presents bleaching agent going near external surface of root

Question 19

what are effects on soft tissue of bleaching;
short & long term exposure

Answer 19

Short term:
- minor ulceration/irritation
- plaque reduction
- aids wound healing

Long term:
- delayed wound healing?
- PDL harm?
- Mutagenic potential?

Question 20

what are the 2 general types of composite veneers you can get?

Answer 20

• direct
• indirect