BLEACHING

1. BLEACHING

2.  INTRODUCTION
 HISTORY
 CAUSES OF DISCOLORATION
 INDICATIONS AND CONTRAINDICATIONS
 MATERIALS USED IN BLEACHING
 CHEMISTRY AND MECHAMNISM
 BLEACHING TECHNIQUES
 ADVANTAGES AND DISADVANTAGES
 CONCLUSION

3. DEFINITION
The lightening of the color of the tooth through
the application of chemical agents to oxidize
the organic pigmentation in the tooth is
referred to as bleaching.

4. HISTORY
 1300’s -tooth whitening.
 14th century, Guy De Chauliac -(Honey +Burnt salt +vinegar) -This was
done for over 300 years.
 18th century, barbers surgeons -“Aquafortis” a solution of nitric acid,
after abrading enamel with coarse metal files to whiten teeth.
 1848,- non vital tooth bleaching with chloride of lime was practiced.
 1864 -Truman used chlorine from calcium hypochlorite and acetic acid
for non vital tooth bleaching. The commercial derivative of this, known
as Labarrque’s solution, was a liquid chloride of soda.
 1868,- bleaching of vital teeth was attempted.
 1872,- Oxalic acid was used to lighten nonvital teeth.
 1877,- first publication for bleaching was given by Chappel, who used
Oxalic acid.
 1878, -Taft used chlorine compounds and solutions for bleaching teeth.
 1884,- Harlan used hydrogen peroxide for the first time which he called
as hydrogen dioxide.
 1889, Kirk used electric current to accelerate the bleaching reaction by
activating the bleaching agent.

5.  1895,- Garretson published the first report of bleaching non vital teeth.
 1900’s, Superoxol (30% hydrogen peroxide) was introduced by a
manufacturing company.
 1911, Rosenthal proposed using light (ultraviolet waves) to accelerate
bleaching reaction.
 1918, Abbot used high-intensity light, raising the temperature of the
hydrogen peroxide rapidly to accelerate the chemical process of
bleaching.
 1924, Prinz recommended using heated solutions consisting of Sodium
perborate and superoxol for cleaning the pulp cavity.
 1950’s and early 1960’s, Pyrozon (ether peroxide) was used effectively for
non-vital bleaching.
 1961, Spasser described Walking Bleach Technique.
 1971, Messing used Sodium hypochlorite as a bleaching agent.
 1976, Nutting and Poe introduced the walking bleach technique which
uses 35% hydrogen peroxide and sodium perborate for nonvital
bleaching.

6.  1989,- Haywood and Heymann introduced “Night guard vital bleaching”
(10% carbamide peroxide).
 1992, -Rembrandt introduced whitening toothpastes and enzyme based
dentifrices.
 1994.- Argon and carbon dioxide lasers and plasma arc activated
bleaching was introduced.
 1998,- Vachon et al recommended 10% Carbamide peroxide as a
bleaching agent.
 1999, -Diode laser was used as a vector in tooth whitening.
 2001,- Nathoo et al has done some studies to evaluate the effectiveness of
external tooth bleaching agents using both spectrometer and visual
evaluation of colour changes using the Vita Lumin shade guide

7. DISCOLORATION
 INTRINSIC DISCOLORATION
Discoloration is a result of change in the structural form or the
composition of dental hard tissues
 EXTRINSIC DISCOLORATION
Discoloration present on the enamel or aquired pellicle generally of
metallic or nonmetallic origin
 INTERNALIZED DISCOLORATION
Stains that occur subsequent to dental development, entering hard
tissues through enamel defects.

9. INTRINSIC DISCOLOURATION
Metabolic causes
 Alkaptonuria,-brown
 congenital erythropoitic
porphyria –red-purple-brown
 congenital hyperbilirubinaemia-
yellow green
 Deficiency of vitamins-A,C,D
 Cerebral palsy,renal
damage,allergies
Inherited causes of discoloration
 Amelogenesis Imperfecta
 Dentinogenesis Imperfecta
 Dentinal dysplasias

10. Iatrogenic causes
Endodontically Related
 Pulp Tissue Remnants
 Intracanal Medicaments
 Obturating materials
Restoration Related
 Amalgam
 Pins and posts
 composites

11.  Tetracycline:
Tetracycline is a chelating agent for calcium, forming tetracycline
orthophosphate.
 Chlortetracycline (Aureomycin): Gray-brown stain
 Dimethylchlortetracycline (Ledermycin): Yellow stain
 Doxycycline (Vibramycin): Does not cause staining
 Oxytetracycline (Terramycin): Yellow stain
 Tetracycline (Achromycin): Yellow stain
 minocycline
Systemic medications

12. Tetracycline staining
depending on sevearity
First – degree tetracycline stain
Second Degree Tetracycline
Staining
Third Degree Tetracycline Staining Fourth degree of tetracycline stain.

13. Jordan and Boksman have proposed three categories of discoloration of the dentin:
 Light yellow or gray stain
 Yellow-brown or deeper gray stain
 Brownish-yellow or blue-gray stain with distinctive banding
Factors affecting the discoloration
•Age at the time of administration:
•Dosage
•Duration of administration
•Type of tetracycline

14. FLUOROSIS STAINING
MILD
MODERATE
PITTING
 High concentration of
fluoride that is more than 4
ppm causes moderate to
severe discoloration
Prevalence:Maxillaryinciso
rs, molars and
premolars

15. TRAUMA RELATED
 Pulp necrosis
 Dentin
Hypercalcification
 Intrapulpal Hemor
rhage
o Staining from Pre-
eruption trauma:
Direct and Indirect

16. Idiopathic causes of discoloration
 Ageing
 Molar incisor
hypomineralization
(MIH)

17. EXTRINSIC DISCOLORATION
Metallic
 Occupational exposure to
metallic salts and
with a number of medicines
containing metal salts.
 Characteristic black staining
of teeth in people using iron
supplements.
 Cu causes a green stain in
mouth rinses containing Cu
salts.
 AgNO3 salt used causes a
grey colour.
 Stannous fluoride causes a
golden brown discoloration.
Non-metallic
• Are adsorped onto tooth
surface deposits such as plaque
/ acquired pellicle.
•Aetiological agents include
Diet. Beverages (Tea, Coffee)
Tobacco.
•Mouth rinses. Other
medicaments.
•Staining effect due to
prolonged rinses with
chlorexhidine.
•Chromogenic Bacteria

18. CLASSIFICATION OF EXTRINSIC STAIN
Nathoo has developed three classifications of extrinsic
dental stain:
 N1 type dental stain or direct dental stain: Colored
material (chromogen) binds to the tooth’s surface and
causes discoloration.The color of the chromogen is
similar to that of dental stain.
 N2 type dental stain or direct dental stain: Colored
material changes color after binding to the tooth.
 N3 type dental stain or indirect dental stain: Colorless
material or a pre-chromogen binds to the tooth and
undergoes a chemical reaction to cause a stain.

19. INDICATIONS OF BLEACHING
 Fairly light discoloration, on the surface, or in the enamel as opposed to
the dentin
 Evenly distributed discoloration on individual teeth, without dark bands
or white spots.
 Teeth are yellowed as their innate color or as a consequence of aging
 Consistent discoloration on all visible teeth, and matching large
amalgams or crowns is not required (these can be later replaced to
match the lighter colors of successful bleaching).
 Fairly heavy and even enamel, with no pits, fissures, or grooves
 Hemorrhagic discoloration
 Discoloration of anterior teeth after root canal treatment.
 Medication discoloration
 Teeth that exhibit color banding from tetracycline require special
procedures to minimize the band effect.

20. CONTRAINDICATIONS
 Sensitive teeth i.e. severe cases of attrition, abrasion, erosion or abfraction
 Teeth with Opaque white spots
 Teeth with extremely large pulps, which may precipitate sensitivity
 Severe loss of enamel,Cracks on enamel or hypoplastic or severely undermined enamel.
 Extensive silicate, acrylic or composite restoration
 Discoloration in the gray, blue gray or black range does not respond well to bleaching and tend
to darken more rapidly.
 Discoloration from metallic salts, particularly silver amalgam.
 Patients with emotional or psychological problems do not make good candidates for bleaching.
 Suspected or confirmed cases of Bulimia as application of bleaching agents in such patients
may result in acute pulpitis.
 Patients with generalized dental caries and leaking restorations
 Teeth slated for bonded restorations or orthodontic bracketing as oxygen produced during
bleaching interferes with the chemistry of bonding agents and will induce bonding failure.
 Latex allergy, if a rubber dam, cannot be used in power bleaching.

21. THE BLEACHING MATERIALS
 There have been numerous changes to materials since
home bleaching materials were introduced.
 First generation materials were in liquid form. These
materials did not remain in trays for a long time.
 Second generation materials are currently available
which are more viscous and in gel form. This is to stop
materials leaching out of tray and causing soft tissue
irritation
 Third generation differ in their vehicle and color.

22. GENERAL COMPOSITION OF BLEACHING GELS
 Carbamide peroxide
 Hydrogen peroxide and sodium hydroxide
 Non- hydrogen peroxide containing materials i.e.
sodium perborate
 Thickening agent carbopol or polyx
 Urea
 Vehicle- glycerin, dentifrice, glycol
 Surfactant
 Preservatives
 Flavorings
 Fluoride

23. INDIVIDUAL MATERIALS USED FOR BLEACHING
Hydrogen peroxide.
 It is a clear, colorless, odorless liquid, stored in lightproof amber
bottles. It is unstable and should be kept away from heat, which
could cause it to explode.
 30 to 35% stabilized aqueous solutions (Superoxol)
 Hydrogen peroxide is caustic and burns tissues on contact,
releasing toxic free radicals, perhydroxyl anions, or both. High-
concentration solutions of hydrogen peroxide must be handled
with care as they are thermodynamically unstable and may
explode unless refrigerated and kept in a dark container.

24. Sodium Perborate.
 oxidizing agent available in a powdered form
 contains about 95% perborate, corresponding to 9.9% of the
available oxygen.
 decomposes to form sodium metaborate, hydrogen peroxide, and
nascent oxygen.
 Available as monohydrate, trihydrate, and tetrahydrate.
 Along with hydrogen per-oxide used in walking bleach technique.

25. Carbamide Peroxide
 Urea hydrogen peroxide, is available in the concentration range of
3 to 45%.
 popular commercial preparations contain about 10% carbamide
peroxide,
 Solutions of 10% Carbamide peroxide break down into urea,
ammonia, carbon dioxide, and approximately 3.6% hydrogen
peroxide.
 Preparations include glycerine or propylene glycol, sodium
stannate, phosphoric or citric acid, and flavor additives.
 carbapol, a water-soluble polyacrylic acid polymer, is added as a
thickening agent

26. OTHER VITAL BLEACHING MATERIALS
 peroxymonosulphate,
 peroxide plus metal catalyst
 Oxireductase enzymes.

27. Chemistry and mechanism
High molecular weight
Complex organic
molecules (chromogens)-
unsaturated double carbon
bonds
+
Bleaching agent
Low molecular weight organic
molecules ( relatively
colorless)-saturated carbon
bonds

28. MECHANISM OF ACTION
‘Redox reaction’.
In this process the oxidizing agent has a free radical with
unpaired electrons, which it gives up, becoming reduced. The
reduced agent (i.e. the substance being bleached) accepts the
electrons and becomes oxidized.
AT LOW PH
 H2 o2 H2O + O(Weaker free radical)
H+HO2 (Lower percentage of stronger free radical)
AT HIGH PH (9.5 - 10.8.)
 H2 o2 H2O + O(Weaker free radical)
H+HO2 (higher percentage of stronger free radical)

29. Saturation point
 As bleaching proceeds, a point is reached at which only
hydrophilic colorless structures exist. This is a
materials saturation point.
 Lightening then slow down dramatically
 Loss of enamel becomes rapid, with the remaining
material being quickly converted into carbon dioxide
and water.

30. Mechanism of each material
1. H2O2: (30-35%)
- Produced and regulated in the body i.e eyes, spleen, liver, etc.
- SUPEROXOL -30% H202, Starbrite-35%
 H2O2 H2O + [O]
 H2O2 H + OOH
 H2O2 OH + OH
 HOO +OH H2O + [O] and OOH [O] + H
- Action of H2O2 the oxidation removes some unattached organic
Matter from the tooth without dissolving the enamel matrix but
also may change the discoloured portion to a colourless state.

31. CARBAMIDE PEROXIDE
 Night guard bleaching 5%, 10%, 16% etc.
 Carbamide peroxide 3.6% H2O2 + 7% urea
 H2O2 H2O +[O]
 Urea NH 3 + CO2
 H2O 2 is active ingredient
 Urea raises the pH of the solution(5 to 6.5)
 Carbopol – stickier and prolongs oxygen release.

32. SODIUM PERBORATE
 Monohydrate, Trihydrate, Tetrahydrate.
 Used in walking bleach technique
 a) Na perborate + H2O2 Na.Metaborate + H2O +[O]
 b) Na perborate + H2O Na.Metaborate + H2O2

33. Diagnosis and case selection
 Vitality
 Caries
 Cracks
 recession , exposed dentine
 Developmental defects

34. Preparation of the patient
 Protective draping and eye wear
 No local anesthesia is administered (vital)
 Oraseal/orabase application on labial and
lingual tissues
 Application of vaseline on lips
 Placement of rubber dam

35. PREPARATION OF TEETH TO BE BLEACHED
Application of Orabase/Vaseline

36. Rubber dam of heavy
gauze is used
Punched holes –smaller
in size

37. Stabilization in the
cervical areas with dental
floss

39. BLEACHING OF VITAL TEETH
The techniques used for bleaching of vital teeth include: -
IN-OFFICE BLEACHING: Also called as Chairside bleaching.
•Thermo/Photo Bleaching
•Bleaching using Mc Innes solution
•Power Bleaching
DENTIST PRESCRIBED HOME-APPLIED BLEACHING: -
•Matrix bleaching-or night guard vital bleaching
OVER-THE-COUNTER KITS
Whitening strips
Whitening pastes
Tray-based bleaching systems

40. In office bleaching
a)Thermocatalytic method Moisten gauze
Place cool wet gauzes

41. Apply etching solution
(37%phosphoric acid)
Wash the etching solution
After 20 secs Chalky white appearance

42. SUPEROXOL Wet the gauze
Apply saturated gauze
to labial surface

43. On lingual surface
Protection lenses
for the pt

44. 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.

45. Add new solution at
every 4 to 5mins
Use a timer

46. Removal of dam,
wiping, rinsingand
neutralisation with
Na gel

47. b)Bleaching agent – Old / New McInnes solution
chen,xu and shing (1993)
Old Mc inns(Acidic
medium)
New Mc inns(Alkaline
medium)
Ratio Ratio
Bleaching
enamel
a) 30% H2O2 5 parts 30% H2O2 1 part
Etches
enamel
b) 36% HCl 5 parts
Removes
surface
debris
0.2% ether 1 part
constituent constituent
20% NaOH 1 part
0.2% ether 1 part

48. New Mc Innes solution
 Chen,Xu and Shing(1993)
 HCL replaced by NaOH 20%
 NaOH helps in the decomposition of H2o2
 Decreases the calcium dissolution.
 Loss of contour is minimized.(Nagarani et al)

49. Night guard bleaching
 NGVB,
 Dentist prescribed home applied technique,
 Dentist home bleaching
 Matrix bleaching
 Mouth guard bleaching
Introduced by Haywood and Heymann in 1989.(10% cp)

50. Night 6-7 (nighttime)hrs for 4-6 wks
Daytime 3-4 hrs/1-3 wks (60-90 mins)

51. Heat water 1.5 minutes in
Microwave
Submerge tray and wave
to soften
Insert & form by hand
then suction
Occlude into softened tray

52. ADVANTAGES
 Very little clinical time involved
 More economical than power bleaching
 Bleaching at the convenience of the patient.
DISADVANTAGES
 Patients involvement in the treatment
 Long duration of the treatment

53. Contraindications to NGVB
• Unrealistic expectations by the patients
• Unwilling to comply with at-home treatment
• Excessive existing restorations not requiring
replacement
• Patient will not tolerate taste of product
•Pregnant or nursing mother (for psychological
reasons, not physical concerns).

54. ENAMEL MICRO ABRASION
 Dr.Walter Kane(1916)
 McCloskey(1984)
 Croll & Cavanaugh(1986)-Enamel
microabrasion.
Modified pumice quartz microabrasion technique
18% HCl-Pumice-Quartz

55. M ICROABRASIONTECHNIQUE

56. OVER THE COUNTER PREPARATIONS
-Thin,flexible polyethylene strips coated one side
with a film of H2O2
•whitening gel is a viscous polyacrylic acid polymer
gel (Carbopol®,b) of glycerin and water containing
5.3% hydrogen peroxide at approximately 5.8 pH
- Worn for 30mins, twice a day
- Duration: 6% coated H2O2 worn over 14 days
10% coated H2O2 worn over 10 days
Adv:
• No tray is needed
• Less visible
• No gagging, salivation, speech problem, jaw
joint problem.
• More convenient & compatible
b) Home bleaching kits

57. Whitening toothpastes
 More abrasive than usual
 Chemical removal of surface pellicle
 Toothpastes containing peroxides
 Prophylaxis paste containing hydrogen peroxide
 Toothpaste containing enzyme-PAPAIN,
BROMAINE

58. NONVITAL BLEACHING
1. In office bleaching
2. Walking Bleach
3. Modified walking bleach
4. Intentional endodontics and non vital bleaching

59. Non vital bleaching:
In office bleaching
Isolate with rubber dam
Remove GP and
seal the canal

60. Remove debris and
Surface stains
Cotton pellet saturated
With 35% H2O2

61. Place gauze both
labially and lingually
to facilitate external
bleaching

62. Labial heating plate
1min, 710c
Insert heating tip in to pulp chamber

63. Walking Bleach(Nutting and Poe
1976/Spasser1961)
S,perborate+ 35% H2O2
Paste
H2O2 cotton pellet seal
Anderson et al(1994) :(Spasser-1961) Suggested the use of
sodium perborate and H2O instead of H2O2 to prevent
cervical resorption.

64. Modified walking bleach technique
Internal non vital power bleaching
 Hydrogen peroxide gel 35% placed in pulp chamber
and activated by either light or heat
 50 to 60 degrees for 5 mins
 Gel is removed, rinsed and dried.
 Walking bleach is instituted between appointments.

65. •Leonard and StettemBrim et al 1997 Inside-Outside
Bleaching technique
•Combination of mouth guard and intracoronal bleaching
techniques.
•Carbamide peroxide is injected into canal orifice and the
tray filled with gel is placed for 1-2 hours
•within 4-5 days.
Intentional Endodontics and Intracoronal bleaching
•-1982Abou-Rass
•Treatment modality for severe tetracycline stains
•Not followed presently
•1998-follow up report with permanent esthetic results.
Inside-Outside Bleaching technique

66. POWER BLEACHING
 Power bleaching is a term given to
accelerated ,in office tooth whitening
procedures using either a Xenon plasma arc
curing light or a laser
 Plasma arc lamp or laser is used
 Liquid rubber dam
ADVANTAGES
 Time factor
 Avoids problems of home bleaching
DISADVANTAGES
 Caustic nature of 35-50% HP
 Increased in office time
 Dehydration of teeth resulting in false light
shade
 expensive

67. Conventional bleaching light:
- Enhance the bleaching action of H2O2 simply by
adding heat
- Slow and uncomfortable for the patient
Metal halide lamps
Requires 20 mins passes provides heat
Tungsten-Halogen curing light:
- Curing light provides heat
-Time consuming process(40-60sec/tooth)
Xenon Plasma arc light(power bleaching)
- Non laser, high-intensity light produces a great deal
of heat.
Adv:Very fast 3sec/tooth
Dis adv:Thermal trauma to the pulp and surrounding
soft tissues

68. LASER ASSISTED BLEACHING
1. All kinds of stains including
tetracycline and non-vital teeth.
2. Photochemical, not photothermal
3. Unique alkaline gel – no enamel
etching
4. No home bleaching trays
5. Takes approximately one hour
6. Liquid rubber dam

69. Argon laser:
 A true laser is delivered to
chemical agent
 488nm WL, Blue light, absorbed
by dark colour
 Action is to stimulate the catalyst
in the chemical.
Adv: No thermal effect, Less
dehydration of enamel,
Less time(10sec/tooth)
TYPES OF LASERS IN BLEACHING

70. Carbon dioxide laser:(10,600nm)
• Invisible infrared light, energy is emitted in
the form of heat
• Directly interacts with catalyst/peroxide and
• with argon laser removes the stain
regardless of the tooth colour
Diode laser light (power bleaching)
- True laser produced from a solid state
source
- It is ultra fast 3-5 sec to activate the
bleaching agent
Adv: Produce no heat

71. BEFORE AFTER

72. Other techniques
Waiting room bleaching (35% CP)
 Uses custom made tray
 gel injected from syringe under hot
water
 Placed in mouth, excess wiped
 Asked to sit in waiting room for 30
mins
 Gel suctioned ,rinsed and dried.

73. Compressive Bleaching technique
 Power bleaching technique reported by Miara
 35% HP gel
 Custom made tray is sealed using light cured
resin material
 Light activated for 30 mins
Ultrasonic technology(Soni white)
•Uses ultrasonic technology with 6-7.5% HP
gel
•Two cycles of 5 mins each

74. Effects on restorative materials
 Haywood and Heymann (1991) have noted no significant color
changes other than the removal of extrinsic stains around existing
restorations.
 Bleaching has been shown to increase the micro leakage of existing
restorations. Restorations may need to be replaced after bleaching
 Amalgam restorations when treated with bleaching agents may cause
micro structural changes
 Fired porcelain showed a slight change after being immersed in the
bleaching gel for three 2- hour periods a day for 5 weeks.
 Provisional restorations such as those using intermediate restorative
material (IRM) may be affected by hydrogen peroxide.

75. Effects on bonding
 Reduces the bond strength between restoration and enamel
 More effect with acetone based bonding agents
 Inhibition of polymerization of resins.
Effect of heat and light
 10 degree rise can double the rate of
reaction.
 Light accelerating the rate of chemical
bleaching of teeth was reported in
1918 by Abbot

76. Complications
1. Gingival irritation
2. Tooth sensitivity
3. Cervical resorption
4. Spillage of bleaching agents
5. Failure to bleach
6. Over bleaching
7. Brittleness of tooth structure/ Microhardness of enamel
8. Delay Composite Restorations

77. ADVANTAGES OF BLEACHING
 Low cost
 Least invasive i.e. no tooth structure is reduced
 No need for continuous replacement, as with
restorative alternatives
 No chipping or fracturing of the natural
bleached teeth, as tends to occur with
restorative modalities (especially bonding, but
also with laminating or crowning).
 Minimal office time made possible by
combining an initial in-office procedure

78. DISADVANTAGES OF BLEACHING
 The effect of bleaching on natural teeth is not permanent.
 significant when the staining is caused by behaviors the patient is unwilling to
give up, such as smoking or drinking coffee and tea.
 It requires more than one or two sessions.
 It is not effective for all forms of discoloration, such as the banding seen in
severe tetracycline staining.The banding effect will remain, albeit somewhat
lighter in color.
 cannot totally correct opacity or white spots frequently seen in fluorosis.
 bleaching cannot alter the shape or form or position of a tooth, as can be done
with bonding, laminating, or crowns.
 Bleaching is inappropriate and even dangerous for some problems. For example,
bleaching is contraindicated when the surface, thickness, and health of the
enamel has been compromised for any reason, ranging from microcracks that
have allowed the stain to permeate the tooth or thinned enamel seen in many
systemic diseases or in some older persons.

79. CONCLUSION