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1. B L E A C H I N G
01. Introduction.
02. Definition
03. History
04. Factors of Discoloration
a. Intrinsic
b. Extrinsic
05. Indication
06. Contraindication
07. Materials used for bleaching
08. Mechanism of action
09. Bleaching techniques
a. Vital teeth
b. Non vital teeth
10. Other methods
a. Lasers
b. Enamel microabrasion
c. Power bleaching
1

2. INTRODUCTION:
Bleaching is an age old treatment, which has been performed
over a century.
The current trend towards cosmetic dentistry has generated
more interest in bleaching as patient’s are asking for whiter and
more beautiful teeth. Our society tends to dislike yellowing of teeth
that comes with age or by various stains.
White teeth are not only considered attractive but are also
indicative of nutritional health, self esteem, hygiene pride and
economic status.
Discoloured teeth on the other hand have a far reaching effect
on an individual both socially and psychologically.
The different treatment modalities available are:
 Bleaching.
 Veenering.
 Jacket crowns.
 Micro abrasion etc.
Out of all these bleaching is the most commonly used
technique, least expensive with maximum conservation of tooth
structure.
DEFINITION:
Whitening of a tooth through the application of
chemical agents to oxidize / reduce the organic
pigmentation in the tooth is termed as bleaching.
2

3. HISTORY:
For vital tooth:
 1877: 1st
publication for bleaching by Chappel who
used oxalic acid.
 1884: Harlen used hydrogen peroxide for the 1st
time,
which he called as hydrogen dioxide.
 1911: Rossentel suggested ultraviolet waves.
 1918: Abbot introduced the combination of H2O2 with
heat and light.
 1989: Heywood and Heymann published an article on
night guard vital bleaching using 10% carbomide
peroxide.
For non-vital tooth:
 1848: Non-vital bleaching with chloride of lime.
 1864: Trumann used chlorine from a solution of
calcium hydrochloride and acitic acid commercial name
was ‘Labarraque solution’.
 1895: Garretson published 1st
report of bleaching non-
vital tooth.
 Early 1900’s: Superoxol (30% H2O2) was introduced.
 1958: Pearson packed superoxol in the pulp chamber.
 1967: “Nutting and Poe” demonstrated walking bleach
using superoxol and sodium perborate to achieve
prolonged effect in pulp chamber.
Discoloration:
 Normal colour of primary teeth – bluish white.
 Normal colour of permanent teeth – Yellowish white.
3

4.  Colour of enamel is determined by the translucency of
enamel, which shows the colour of underlying dentin.
Any alteration in colour may be
Endogenous / Exogenous Physiologic / Pathologic
Refractory index of teeth is 1.5.
Causes for discolouration:
Extrinsic Intrinsic
1. Coffee and tea
stains
2. Cigarette
3. Diet
4. Tobacco
5. Nasmyths
membrane (seen in
children caused due
to reduced enamel
epithelium)
1. Tetracycline stains
a) 1st
degree
b) 2nd
degree
c) 3rd
degree
d) 4th
degree
2. Fluorosis stains
3. Trauma to tooth
4. Systmic condition
a) Erythoblastosis
foetalis
b) Jaundice
c) Amelogenesis
imperfecta
d) Enamel
hypoplasia due to
deficiency of vitamin
A,C,D.
5. Iatrogenic discoloration
a) Amalgam
b) Intracanal
medicaments
(Kerr root sealer,
Grossman sealer, Procosol
sealer).
Tetracycling staining:
 Teeth are more susceptible to tetracycline
discolouration during their formation i.e. during the
second trimester in vitro to roughly 8 years after birth.
4

5.  Tetracycline molecules chelate with calcium and gets
incorporated into the hydroxyapatite crystals.
 It involves predominantly the dentin.
 Severity of stains depends on the time and duration of
drug administration.
4 Degrees:
1st
Degree
- Light yellow, brown stains
- Uniformly distributed
- No banding or localized concentration
- Responds to bleaching in 2 or 3 session
2nd
Degree
- Dark gray stains
- Extensive than 1st
degree
- Responds to bleaching in 4-6 session
3rd
Degree
- Dark gray stains with banding.
- Responds to bleaching best bands will be evident.
4th
Degree
- Does not respond to bleaching.
Fluorosis:
 High concentration of fluoride in more than 4ppm cause
moderate to severe discoloration.
 Prevalence – Premolars, 2nd
molars and mandibular and
maximum incisors.
Types
Mild fluorosis - Brown pigmentation on a smooth enamel
surface
- Responds well to bleaching
Moderate - Opaque fluorosis appear gray with
white flecks on enamel surface.
Severe - With pitting and dark pigmentation
with surface defects.
- Does not respond to bleaching
5

6. Traumatic Injuries:
 Causes rupture of blood vessel in the pulp.
 Causing diffusion of blood into dentinal tubules.
 Dark pink immediate after trauma and changes to
pinkish brown after some days.
Causes: Haemoglobin degrades into hemin, hematin,
hematoiden and haemosidrin.
Hydrogen sulphide produced by bacteria combines
with hemoglobin to dark colour to tooth.
Systemic Condition:
1) Erythroblastosis foetalis: (Rh factor
incompatibility between mother and foetus)
characterized by – breakdown of erythrocytes.
2) Jaundice: Bluish green or brown stains
in dentin caused by bilirubin or biliverdin.
3) Amelogenesis imperfecta: is a genetic
condition which interface with the normal enamel
matrix formation.
4) Enamel hypoplasia: caused by deficiency
of vitamins i.e. A, C, D and calcium and phosphorus.
Iatrogenic discolouration:
a] Trauma during pulp extirpation – hemorrhage
b] Failure to removal of all pulpal remnants.
c] Amalgam restoration cause – dark gray.
d] Gold – dark brown when combined with products of
decay.
e] Break down of restoration i.e. acrylic, silicate and
composite resins can cause the tooth to look grayer
and discolored.
f] Silver containing root canal sealers i.e. “Kerr root”,
“grossman sealer”.
g] Volatile oils → yellowish brown stain.
h] Pins cause → bluish grain stains.
6

7. Indications:
1) Discolouration of anterior teeth – after
R.C.T.
2) Tetracycline stains (mild)
3) Fluorosis
4) Haemorrhagic discolouration.
5) Discolouration due to ageing
6) Medication discolouration
Contraindications:
1) Sensitive teeth
2) Opaque or white spots
3) Pregnancy
4) Lactation
5) Deep microcracks staining
6) Extensive silicate, acrylic or composite restoration.
Materials used for bleaching:
1) H2O2 (30-35%) eg. Superoxol 30%; Starbrite 35%.
(1-10%) Eg. Brite-smile; Natural white.
2) Carbamide peroxide
10% with carbopal, E.g. Ultralite; Opalescance.
10% without carbopal E.g. Gly-oxide; white and brite
10% Carbamide peroxide, Eg. Nu-Smile
3) Sodium perborate
Available as granules, which are powdered later for
use.
S.P. + 30/H2O2  Walking bleach (Paste)
S.P. + H2O  (New) (Liquid).
Bleaching mechanism:
The mechanism is oxidation / reduction process
called as “Redox process”.
In this process the oxidizing agent has a free radical
with unpaired electrons, which it gives up, becoming
7

8. reduced. The reducing agent (i.e. the substance being
bleached) accepts the electrons and becomes oxidized.
Reducing agent Oxidising agent
Tooth Bleaching material
After the process
Tooth is oxidized Bleaching material is reduced
(Organic pigmentation of tooth oxidized)
Mechanism of each materials:
 Hydrogen peroxide in various concentration is the
primary material currently used by the profession in
the bleaching process.
 Current inoffice techniques for vital teeth and walking
bleach technique use 30-35% H2O2.
 H2O2 is produced and regulated in the body and after
involves in wound healing in low concentrations, also
seen in eyes, spleen and liver etc i.e. it is more
biocompatible.
 In high concentration it is bacteriostatic.
 In very high concentration it is mutagenic possibly by
disrupting the DNA strand.
H2O2  H2O+[O] or H2O2  H + OOH or H2O2  OH+OH;
HOO + OH  H2O +[O] and OOH  [O]+H
Action of H2O2 in tooth bleaching is considered to be
oxidation, although the process is not well understood. It
is felt that the oxidizers remove some unattached organic
matter from the tooth without dissolving the enamel
matrix but also may change the discoloured portion to a
colourless state. (Continued long-term treatment will
result in dissolution of the enamel matrix).
8

9. Tetracycline stains are more resistant to oxidation
because the molecule is tightly bound to the mineral in
the enamel prism matrix, during formation and hence is
less accessible to immediate action. Therefore treatment
takes a prolonged time.
H2O2 diffuses through the organic matrix of enamel
and dentin. Because the radicals have unpaired electrons,
they are unstable and will attack other organic molecules
for stability.
Carbamide peroxide:
The majority product in the market for night guard
bleaching use 10% C.P.
C.P  3% H2O2 + 7% urea
H2O2  H2O + 2[O] and Urea  NH3 + CO2.
H2O2 is the active ingredient whereas urea raises the
pH of the solution.
Sodium perborate:
For non-vital tooth bleaching sodium perborate is
used with H2O2 called ‘walking bleach’ technique.
a) Sodium perborate is a white powder which
decomposes into sodium metaborate and H2O2.
S.P.  S. Metaborate + H2O2.
b) When S.P. is mixed with H2O2 it decomposes
into sodium metaborate, H2O and O2.
SP + H2O2  S.m.Borate + H2O + O2.
c) S.P + H2O  S.M.Borate + H2O2.
McInnes solution:
9

10. Old: Contain 30% H2O2 – Bleaches the enamel
36% HCl – Etches the enamel
0.2% Ether removes surface debris
5:5:1
H2O2 bleaches the enamel by a process of oxidation.
HCl increases the penetration of the solution and
helps in faster action.
But HCl has deleterious effect such as;
a) Loss of contour
b) Irritation to gingiva
c) Sensitivity of teeth
So Chen, Xu and Shing (1993) replaced HCl by 20%
NaOH.
NaOH is highly alkaline in nature and therefore
dissolves calcium at a slower rate.
The results suggest that 1:1 mixture of H2O2 with
20%. NaOH is an effective as old McInnes solution and the
calcium dissolved is much less with the new McInnes
solution.
A study by Dr.Versha Nangrani showed that the use
of old McInnes solution resulted in loss of contour of
teeth. The time taken by New McInnes solution was double
than that of old McInnes solution but it did not show loss
of contour of the teeth.
Dr.Shadwala studied the amount of calcium
dissolution with opalescence night guard vital bleaching
and old McInnes solution and found that old McInnes
10

11. solution caused less calcium dissolution as compared to
Night guard vital bleaching. The reason for this was night
guard and vital bleaching uses bleaching action, which
lasts for 6 hours for 2 weeks where as McInnes solution
has to be used only for 5 minutes to 20 minutes.
Treatment planning:
1) Record keeping and photographs
2) Careful diagnosis – Which included: Vitality tests;
any restorations i.e. composite, acrylic etc.
3) Oral prophylaxis and polishing: To get rid of surface
stains and calcium.
4) Preparation of teeth to be bleached i.e.
a. Rubber dam
b. Protection of soft tissue by Vaseline or Orabase.
c. Floss to ligate interdentally to present seepage
of bleaching agents into gums.
d. Gauze saturated with cold water is placed
under the rubber dam.
e. Protective glass
Bleaching of vital teeth
1) In office bleaching
a. Thermocatalytic - Light; Heat
b. McInnes solution – Old; New
2) Nigh guard vital bleaching
3) Over the counter
4) White strips
11

12. In office bleaching
a) Thermocatalytic using light / heat
After the rubber dam placement
 Teeth is covered with 35% H2O2 with Gauze
 The peroxide solution is activated by light / heat.
 Keep the light about 30 cms (13 inches) from the teeth
and direct the beam to the surface to be bleached
temperature ranges from 115°-140°F.
 When heat is used temperature is 46°-60°C.
 Gauze is kept wet by dispensing fresh bleaching
solution.
 Bleaching agent should be kept in contact of light /
heat for 30 minutes.
 After removing the Gauze, wash with copious amount of
warm water and then polish.
 Repeat the procedure till desired shade is obtained.
(Neutralizing the solution with 5.25% NaOCl)
Tungsten halogen curing light.
McInnes solution:
Old New
30% H2O2 – Bleaching 30% H2O2
36% HCl - Etching 20% NaOH
0.2% Ether – Removal of
surface debris
0.2% Ether – Removal of
surface debris
- Rubber dam is applied
- Apply the paste on teeth for 5mts and
repeated after 1 minute in level with cotton applicators.
- Old McInnes solution is neutralized with
baking soda.
12

13. - Copious irrigation of warm water.
- Polish .
Disadvantages of old McInnes solution overview.
1) Loss of contour
2) Sensitivity
3) Irritation to gingiva
Ca dissolution is more
Night guard bleaching (10% carbamide peroxide):
 Make primary impression and pour a cast.
 Make reservoirs on the cast on the labial aspect.
 Prepare the polyresin tray with the help of vacuum form
machine.
 The tray is trimmed and extended 1mm short of the
gingival margin on the labial aspect to avoid irritation
of gingiva by the bleaching material.
 Tray is then tried on the patient’s mouth to check for
fit.
 Instructions are given to the patient to load the tray
with the gel only on the labial aspect and wear the tray
at night during sleep for 6-7 hours for 2 weeks.
 If patient any sensitivity he can discontinue wearing
the tray.
 Patient should be instructed not to bite the tray.
 After tray removal of the tray the patients brushes off
the material.
 Weekly check up should be done.
Disadvantages of night guard bleaching.
- More lab procedures
- Patient complains of gag reflex while
using tray
13

14. White strips:
Which is a thin flexible polyetheline strips which
contains 5.3% hydrogen peroxide in gel form. The strips
are used for 30 minutes twice daily for 14 days.
Non vital bleaching:
1) In office bleaching.
2) Walking bleach (out of office bleaching).
 Establish a lingual opening of sufficient size to provide
access to the pulp chamber and orifice of root canal.
 The root canal filling should be removed to a depth of
2-3 mm apical to cervical line.
 Zinc polycarboxylate or cavit cement should be used to
refill, 1-2 mm coronally to the CEJ.
 Bleaching should never be attempted on any tooth that
does not have a complete seal in the root canal.
1) In office bleaching:
 Rubber dam is placed.
 The pulp chamber is filled loosely with cotton fibres
and the labial surface is covered with a few strands of
cotton fibre to form a matrix for retaining the bleaching
solution.
 35% H2O2 is used to saturate the cotton inside the pulp
chamber and on the labial surface.
 Excess should be wiped immediately.
 A thin tapered instrument can be heated and inserted
into the pulp chamber for 5 minutes in a sequence of
1mt on 15 seconds off.
 It has been established by Caldwell that a non-vital
tooth can with stand a temperature of 73°C without
causing patient discomfort.
14

15.  An alternative to activate H2O2 is the use of light and
heat from a bleaching light.
 The tooth is subjected to 5 minutes exposure and one
replenishes the bleaching agent at frequent intervals.
 The heating instrument and cotton can be removed.
Process can be repeated for 4-6 times or 20-30 minutes
each time placing a new cotton fibre.
 This technique can be used alone or in combination
with walking bleach.
2) Walking bleach (by Nutting & Poe in 1963):
 This procedure consists of filtering the prepared
chamber as described previously with a paste of 35%
H2O2 and sodium perborate.
 When sealed into the pulp chamber, it oxidizes and
discolours the stain slowly continuing its activity for a
larger period.
 A small pledget of cotton wool in placed over the paste
and the cavity is sealed with polycarboxylate or cavity
cement.
 Patient should return in 4-7 days.
Modified walking bleach: (Leonard and Stettem Brim
et.al. 1997)
 Fabrication of the study model.
 Light cured composite are placed on the tooth or teeth
to be treated. This acts as a reservoir to be created in a
vacuum processed mouth guard whose thickness is 0.2-
03 inch.
 Mouth guard is trimmed at the cervical margins on the
labial and lingual portions and tried on patients mouth.
 The G.P. in the root canal is sealed off from the pulp
chamber at the cervical line and sealed with GIC.
15

16.  Patient is taught how to inject 10% carbomide peroxide
into the canal orifice and into the mouth guard with a
syringe.
 Patient can use the mouth guard while sleeping.
 At the end of the daily treatment, patient rinses the
mouth and then places a cotton pellet to prevent the
food from getting into the opening.
 Treatment proceeds for 3-4 days.
Anderson and L.A.F Punenta (1999) Spassier
suggested the use of sodium perborate and H2O as a
walking bleach technique instead of H2O2 to prevent
cervical resorption. Sodium perborate breaks down to
sodium metaborate and H2O2. This showed satisfactory
results.
Enamel micro abrasion:
 In 1916 Dr.Walter Kane of Colorado springs used 18%
HCl with a warm instrument to successfully remove
stains associated with endemic fluorosis.
 In 1984 McCloskey found that brown fluorosis stains
can permanently be removed by rubbing the enamel
with 18% HCl acid soaked cotton pellet wrapped around
amalgam condenser.
 Two year later Croll and Cavananaugh developed a
similar techniques that involves pressure application of
18% HCl with pumice to achieve colour modification.
This was called enamel micro abrasion.
 Dr.Croll believed that the acid abrasive action of the
compound gives the enamel surface a superfine
polishing as a microscopic layer of enamel is removed.
The freshly polished surface then develops or shiny
glass like texture.
16

17.  Jacobson – Hunt (1988) reported 30 second application
of the acid abrasive compound using a mandrel and
gear reduction handpiece on extracted human teeth
which resulted in a enamel loss of less than 200 µm.
 In 1889 Kendell reported 5 second application of HCl
acid pumice mixture removes 46 µm of enamel which
should be considerably tolerable.
 Important concern of HCl pumice abrasion is the low
viscosity and high concentration of 18% HCl.
To eliminate this problem and ensure safety the
viscosity of the acidic solution is increased by mixing 18%
HCl acid with quartz particles so that the solution takes
on a water soluble gel like form. This came to be known as
‘modified 18% HCl acid quartz – pumice abrasion
technique’.
Procedure:
 Gingiva is protected by a layer of petroleum jelly.
 Tooth is isolated will rubber dam.
 Teeth is dried and the paste consisting 18% HCl acid
quartz – pumice particles are applied with cotton tip
application to the stained areas of enamel.
 Paste is allowed to remain for 5 seconds and then for
10 seconds the enamel microabrasion is effectuated
with a cotton swab pressure.
 After 10 seconds a marked degree of success is
obtained and stain was removed.
 After 15 seconds, the enamel of the teeth turned to a
normal shade.
17

18.  At the end of treatment teeth is washed and dried with
a neutral sodium gel.
 In this process the quartz particles convert the acid
into a gel form and functions as an additional abrasive
agent.
 Patient is reviewed after 6 months.
Advantages:
 Relatively economical;
 No lab procedures
Lasers:
The action is to stimulate the catalyst in the
chemical. There is no thermal effect and less dehydration
of enamel.
 Argon laser of 488 nm wave-length for 30 seconds to
evaluate the activity of bleaching gel. As the laser
energy is applied, the gel is left in place for 3-4 minutes
and then removed. This procedure is repeated for 4-6
times.
 Another product uses Ion laser technology. Argon laser
is used as described before. Then CO2 laser is employed
with another peroxide solution to provide penetration of
the bleaching agent into the tooth to provide bleaching
below the surface.
 Argon laser is in the form of blue light and is absorbed
by dark colour. It is an ideal instrument to be used in
tooth whitening when used with 50% H2O2. The affinity
to dark colour ensures that the yellow brown colour can
be easily removed.
 CO2 laser no colour requirement. It is unrelated to the
colour of tooth and energy is emitted in the form of
18

19. heat. It is invisible and penetrates only 0.1 mm into
water and H2O2 where it is absorbed.
This energy can enhance the effect of whitening after
the initial argon laser process.
Power bleaching:
 This is done using xenon plasma arc curing light or a
laser.
 This is a light cured resin gel that is applied on the
gingiva and areas of the teeth that you do not wish to
bleach. (Rubber dam is not required)
 Advantages – It is faster
 Disadvantages – unlike rubber dam, lips and soft
tissues are not protected.
Diode laser light:
 A true laser light produced from a solid-state source. It
is ultra fast, taking 3-5 seconds to activate the
bleaching of agent.
 This type of laser produces no heat.
Complications of internal bleaching:
1) Cervical resorption
- H2O2 percolates from the access cavity to
the root surface through the acid treated patent
dentinal tubules.
- This stimulates an inflammatory
response tending to dentin resorption.
2) Spillage of bleaching agents
- Oxidising agents is easy to handle as a
paste than a solution.
19

20. - Use rubber dam.
- Any spillage is diluted immediately with
copious volume of H2O.
3) Failure to bleach
- Commonest is discolouration by mild
ions in silver amalgam.
- H2O2 improperly stored or expired.
- In complete removal of composite or GIC
which prevents the bleaching agents to penetrate into
dentinal tubules.
4) Brittleness of crown
- Bleaching causes coronal tooth structure
to become brittle, this may be caused due to removing
of all discoloured dentin rather than using the
bleaching agent the discolour dentin.
FERENCES:
1. “Bleaching Teeth” – Ronald Fieman, Roland Goldstein,
David Garber, Quintessence Publishing Company, Inc.,
1987.
2. History, safety and effectiveness of current bleaching
technique and application of the night guard vital
bleaching technique, Haywood Van B. Quintessence
International, 1992; 23; 471-488.
3. Estimation of dissolution of calcium by old McInnes
solution and new McInnes solution, R.Nageswar Rao
and Nangrani V., Indian Endodontic Journal, 1998; 50-
53.
20

21. 4. “Bleaching teeth” new materials and new role, Roland
Goldstein, JADA, 1987; 43-52.
5. Historical development of whiteners “clinical safety and
efficacy”, Haywood Van B., Dental Update, 1997, April.
6. Laser assisted bleaching: An Update, JADA, 1998; 129;
1484-1487.
7. Non-vital tooth bleaching: A two-year case report,
A.T.Hara, L.A.F. Pimenta, Quintessence International,
1999; 30; 748-754.
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