Tooth Whitening

Question 1

what are the extrinsic causes of tooth discolouration

Answer 1

smoking
tea
coffee
red wine
chromogenic bacteria
chlorhexidine
iron supplements

Question 2

what are the intrinsic causes of tooth discolouration

Answer 2

fluorosis
tetracycline
non-vitality
physiological
dental materials
porphyria
cystic fibrosis
sickle cell anaemia
hyperbillirubinaemia

Question 3

what should the first method of tooth whitening for extrinsic staining be

Answer 3

hygiene phase therapy

Question 4

what are the 2 types of bleaching

Answer 4

external vital bleaching
internal non-vital bleaching

Question 5

what does bleaching do to extrinsic compounds adhered to the tooth

Answer 5

oxidises them leading to smaller molecules which are not pigmented
cause ionic exchange in metallic molecules leading to lighter colour

Question 6

what is the action of hydrogen peroxide

Answer 6

forms an acidic solution in water
breaks down to form water and oxygen
free radical per hydroxyl is formed which is the active oxidising agent

Question 7

what is carbamide peroxide

Answer 7

active ingredient which breaks down to produce hydrogen peroxide and urea

Question 8

what is carbopol

Answer 8

thickening agent which slowly releases oxygen and increases viscosity of the gel making it stay where you put it
allows slow diffusion into enamel

Question 9

what is the action of urea

Answer 9

raising pH
stabilising hydrogen peroxide

Question 10

what does surfactant do

Answer 10

allow gel to wet the tooth surface

Question 11

what are potassium nitrate and calcium phosphate

Answer 11

tooth desensitising agents

Question 12

what does fluoride do

Answer 12

prevent erosion
desensitising

Question 13

what are the factors affecting bleaching

Answer 13

time
cleanliness of tooth surface
concentration of solution
temperature

Question 14

what do you do before you start tooth whitening

Answer 14

ensure patient is dentally fit and no leakage around carious cavity margins
take initial shade

Question 15

what do you need to warn the patient about

Answer 15

sensitivity
relapse
restoration colour
allergy
might not work
compliance with regime

Question 16

what are the two types of vital external bleaching

Answer 16

chair side
home

Question 17

what are the advantages of chair side bleaching

Answer 17

controlled by dentist
can use heat/light
quick results for patient

Question 18

what are the disadvantages of chair side bleaching

Answer 18

time for dentist
uncomfortable
results wear off quicker
expensive

Question 19

what is the technique for chair side bleaching

Answer 19

thorough cleaning of teeth
rubber dam
gingival mask
bleaching gel applied to tooth
heat/light applied
wash/dry/repeat
takes 30mins to an hour

Question 20

what is home bleaching

Answer 20

patient gets custom made trays and bleaches slowly over several weeks

Question 21

when getting soft splints made for at home bleaching what do you need to tell the lab

Answer 21

stop 1mm short of gingival margin
buccal spacer to allow for placement of gel

Question 22

what is the technique for at home bleaching

Answer 22

full mouth cleaning in surgery
fit trays
instructions for use
brush and floss teeth at home
load tray with 1mm squared buccal on each tooth
fit tray in mouth for 2 hours but preferably overnight

Question 23

when would you bleach teeth

Answer 23

age related darkening
mild fluorosis
post smoking cessation
tetracyclin staining

Question 24

what are the problems with bleaching

Answer 24

sensitivity
wears off
cytotoxicity
gingival irritation
tooth damage
damage to restorations
problems with bonding to tooth

Question 25

what are the predictors of sensitivity

Answer 25

pre-existing high concentration of bleaching agent frequency of change bleaching method gingival recession

Question 26

when would sensitivity resolve

Answer 26

2-3 days after bleaching

Question 27

what does chlorine dioxide do

Answer 27

strips enamel from tooth surface has pH of 3

Question 28

what are the indications for internal non-vital bleaching

Answer 28

non-vital tooth adequate RCT no apical path

Question 29

what are the contraindications for internal non-vital bleaching

Answer 29

heavily restored tooth staining dur to amalgam

Question 30

what are the advantages of internal non-vital bleaching

Answer 30

easy conservative patient satisfaction

Question 31

what are the risks of internal non-vital bleaching

Answer 31

external cervical resorption

Question 32

what is the technique for internal bleaching

Answer 32

record shade prophylaxis rubber dam remove filling from access cavity remove GP from pulp chamber and place RMGIC over GP to seal canal remove dark dentine etch internal surface place 10% carbamide peroxide gel cotton wool over this seal with GIC repeat procedure at weekly intervals

Question 33

how long does internal bleaching take

Answer 33

3-4 visits

Question 34

what is combination bleaching

Answer 34

make access cavity and remove GP, make bleaching tray and place bleach in access cavity and tray and keep in the whole time (week)

Question 35

what does micro abrasion do

Answer 35

remove discolouration limited to outer layers of enamel

Question 36

what are indicators for microabrasion

Answer 36

fluorosis demineralisation with staining post ortho demineralisation prior to veneering

Question 37

what is the micro abrasion technique

Answer 37

clean teeth rubber dam mix 18% HCl and pumice apply to teeth rub with prophy cup wash repeat 10x remove rubber dam polish teeth with fluoride prophy paste apply fluoride gel or varnish

Question 38

what are the advantages to microabrasion

Answer 38

quick easy no long term problems

Question 39

what are the disadvantages to microabrasion

Answer 39

acid sensitivity only for superficial staining works better for brown stains than white marks

Question 40

what does resin infiltration do

Answer 40

changes the refractive index of the white area and makes it look like surrounding enamel

Question 41

what regulations are needed to comply with for tooth whitening

Answer 41

cosmetic products regulations 2012

Question 42

what is the maximum legal amount of hydrogen peroxide allowed in practice

Answer 42

6%

Question 43

what age must you be to use 0.1% to 6% hydrogen peroxide

Answer 43

18

Question 44

what percentage of hydrogen peroxide is allowed on the market in toothpastes

Answer 44

0.1%