Treatment of intrinsic discolouration in children and adolescents

Question 1

intrinsic discolouration in anterior teeth - treatment options

Answer 1

enamel micro abrasion
bleaching
- vital - surgery or home
non vital
- ‘inside outside’ technique
- ‘walking bleach’ technique
Resin infiltration technique (ICON)
localised composite resin
veneers
- composite - direct (free hand or putty guided) or indirect (lab made)

Question 2

pre operative records required for all discoloured teeth

Answer 2

clinical photos
shade
sensibility testing
- check for sensitivity
diagram of defect
radiographs
- only if clinically indicated
patient assessment

Question 3

microabrasion technique

Answer 3

PPE must be worn
patient must be wearing glasses as bib

clean teeth with pumice and water
apply petroleum jelly to gingiva
place rubber dam and wedjets
place sodium bicarbonate guard
- have more sodium bicarbonate available
dry dam and wedjets
rub HCL pumice slurry using slowly rotating rubber cup for 5 seconds
- max 10x 5 second applications
wash directly into aspirator after each 5 second aspiration
fluoride varnish application
- profluorid NOT duraphat
polish with finest soflex (sandpaper) disc
final polish with toothpaste

Question 4

Why are sandpaper discs used to polish enamel following micro abrasion

Answer 4

it changes the optical properties of the enamel making areas of intrinsic discolouration less perceivable

Question 5

micro abrasion indications

Answer 5

demineralisation after fixed orthodontic treatment
fluorosis
trauma to primary incisors

Question 6

how much enamel is lost from the use of a prophy cup with toothpaste?

Answer 6

5-10 microns

Question 7

how much enamel is lost from the use of a prophy cup with pumice?

Answer 7

5-50 microns

Question 8

how much enamel is lost from orthodontic bracket bonding or debonding?

Answer 8

5-50 microns

Question 9

how much enamel is lost from acid etching?

Answer 9

10 microns

Question 10

how much enamel is lost from 10x 5 seconds of HCL pumice microabrasion?

Answer 10

100 microns

Question 11

advantages of micro abrasion

Answer 11

easily performed
conservative
inexpensive
teeth need minimal subsequent maintenance
fast acting
removes yellow-brown, white and multicoloured stains
effective
results are permanent
can be used before or after bleaching

Question 12

microabrasion disadvantages

Answer 12

removes enamel
HCL acid compounds are corrosive
requires protective apparatus for patient, dentist and dental nurse
prediction of outcome is difficult
must be done in dental surgery

Question 13

reviewing micro abrasion -steps

Answer 13

dry teeth after procedure
warn patient to avoid highly coloured food and drinks for at least 24 hours
review patient in 4-6 weeks after procedure and take post op photos

Question 14

active agent used in home vital bleaching and concentration?

Answer 14

10% carbamide peroxide gel

Question 15

active agent and concentration used in chair side vital bleaching

Answer 15

15-38% hydrogen peroxide

Question 16

instructions to patients undergoing vital home bleaching

Answer 16

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, brush tray and rinse with cold water

Question 17

How long does vital home bleaching take to work?

Answer 17

approx 3-6 weeks
tell patient to keep going until acceptable colour

Question 18

10% carbamide peroxide breaks down into…

Answer 18

3% hydrogen peroxide, 7% urea
- breaks down into water, ammonia and carbon dioxide

Question 19

advantages of non-vital bleaching

Answer 19

simple
conserves tooth
original tooth morphology
gingival tissues not irritated by restoration
no lab assistance required for ‘walking bleach’ technique

Question 20

non vital bleaching - indications

Answer 20

adequate root filling
no clinical or radiological pathology
anterior teeth without large restorations
no amalgam staining
no fluorosis or tetracycline discolouration

Question 21

briefly outline the 2 non-vital bleaching methods

Answer 21

walking bleach
- oxidising process allowed to proceed gradually over days
inside out method
- 10% carbamide peroxide gel, can seal if co-operation is an issue

Question 22

non vital ‘walking bleach’ technique steps

Answer 22

root filling removed to below gingival margin
cotton wool with bleaching area placed within access cavity
- cover with dry cotton wool
access cavity sealed with GIC

Question 23

walking bleach application, frequency and regression

Answer 23

renew bleach
- ideally no more than 2 weeks between appointments
stop if no change after 3-4 renewals
- 6-10 shade changes in total
50% regression at 2-6 years

Question 24

combination “inside out” bleaching method

Answer 24

open access cavity
custom made mouthguard
- cut windows in guard of teeth you don’t want to bleach
patient applies bleaching agent to back of tooth and tray
- access cavity must be kept clean - replacing gel removes food debris etc
- 10% carbamide peroxide gel is used
mouthguard worn all the time except when eating and cleaning
gel changed every 2 hours except during the night

Question 25

How to restore the pulp chamber following non-vital bleaching

Answer 25

non-setting calcium hydroxide paste for 2 weeks, seal with GIC
then either:
- place white GP in canal followed by composite resin - enables re-bleaching if required
- incrementally cured composite - no re-bleaching but stronger tooth
veneer or crown prep if regression

Question 26

non-vital bleaching - potential complications

Answer 26

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

Question 27

how to prevent external cervical respiration

Answer 27

place a layer of cement over gp
- prevents bleaching area from getting to external surface of root (walking bleach technique only)
non-setting calcium hydroxide in tooth for 2 weeks before final restoration
- reverses any acidity that might of occurred if above had happened

Question 28

effects on soft tissue on bleach exposure

Answer 28

short term
- minor ulceration or irritation
- plaque reduction
- aids wound healing
long term (potentially)
- delayed wound healing
- periodontal harm
- mutagenic potential

Question 29

what can be used as an adjunct to micro abrasion and bleaching?

Answer 29

tooth mousse
- PP-ACP milk derived protein
suggested use for 2 weeks after bleaching or for 4 weeks for hypominerilsed lesions or mild/moderate fluorosis)
- pea size at night before bed

Question 30

Whta is resin infiltration?

Answer 30

infiltration of enamel lesions with low viscosity light curing resins

Question 31

how does resin infiltration work?

Answer 31

surface layer is eroded, lesions are dried and a resin infiltrant is applied
resin penetrates lesion driven by capillary forces
infiltrated lesions lose discoloured appearance and look similar to sound enamel

Question 32

veneers - considerations to make regarding enamel reduction

Answer 32

overcontoruing increases plaque retention and stagnation at gingival margin
- especially in patients with poor oral hygiene
bond stretch of composite resin to enamel is significantly increased after partial removal of buccal enamel