recent bleaching concepts, materials , cytotoxicity , concentration of bleaching agents

1. Dr.K.Sadasiva , MDS
prof&HOD
Department of conservative dentistry
Chettinad Dental College and Research
Institute
RECENT ADVANCES IN MATERIALS AND
TECHNICAL ASPECTS IN BLEACHING

2. INTRODUCTION
 People with whiter smiles are generally perceived as more
attractive and beautiful.
 And, due to recent advances in bleaching materials and
techniques, tooth whitening or bleaching is more popular
than ever.
 The desire to have brighter smiles has led to increased demand for
the new role of dentists as cosmetic specialists
 It is currently the PREFERRED/ requested cosmetic
procedure.
 Its non-invasive procedure & conserves dental hard tissues,

4. White teeth
Bright teeth
Cutest smile
Aesthetic Dentists
Domain

5. 1864 – Truman - labarraques solution – liquid chloride of soda
1884 – Harlan -used hydrogen peroxide for first time
Early 1900’s – Non vital bleach attempted
1918 – Abbot – in office bleaching
1958 – pearson – Intracoronal bleaching
1961 – Spasser –Walking bleach technique
1965 – Stewart – Thermocatalytic technique – H202 plus external heating
1988 – First commercial bleaching product : white brite
1989 – Haywood and Heymann – nightguard vital bleaching
1989 – Croll- Micro abrasion technique
1994- ADA specifications for safety & efficacy guidelines for bleaching
1996 – Reyto- Laser tooth whitening
FATHER OF MODERN BLEACHING
Dr Van Haywood

7. McInnes solution - The Forgotten Entity for Fluorosis Stains, Case Reports , Sadasiva Kadandale*, Sriram K**, Vijikarthikai Balan , Chettinad Health City Medical Journal
2014; 3(3): 139 - 140

8. Bleaching
• Definition
• The lightening of the color of a tooth through the application of a
chemical agent to oxidize the organic pigmentation in the tooth is
referred to as bleaching.
Sturdevants

9. Ingle classification - Based on etiology
Etiology of Tooth Discoloration
• Patient-related causes
• Pulp necrosis
• Intrapulpal hemorrhage
• Calcific metamorphosis
• Age
• Developmental defects
• Medications
• Dentist-related causes
• Pulp tissue remnants
• Intracanal medicaments
• Endodontic obturation materials
• Restorative materials
Systemic intrinsic causes
• Genetic cause
• Disease related cause
• Metabolic cause
• Drug related cause
Local intrinsic cause
• Pulpal hemorrhage
• Pulp necrosis
• Pulp tissue remnants
• Restorative materials
• Intracanal medicaments and Rootcanal fillings
• Dental caries
• Calcific metamorphosis/ dystrophic calcification
• Root resorption
• Ageing
Extrinsic causes
Cohen classification of discoloration -12th edition

10. Nathoo type 1 (N1) (direct
dental stain)
• Colored material
(chromogen) binds to the
tooth surface.
• Dental stains caused by
tea, coffee, wine,
chromogenic bacteria, and
metals.
• Prevented by oral hygiene
procedures
Nathoo type 2 (N2) (direct
dental stain)
• Colored material changes
color after binding to the
tooth.
• The stains actually are
N1‐type food stains that
darken with time.
• Very difficult to clean and
require professional
cleaning
Nathoo type 3 (N3) ( indirect
dental stain)
• Colorless material or
prechromogen binds to the
tooth and undergoes a
chemical reaction to cause
a stain.
• Discoloration due to redox
reactions.
• Carbohydrate rich foods,
therapeutic agents like
stannous fluoride, and
chlorhexidine.
• Difficult to remove and
require oxygenating layers
to remove.
Nathoo classification and causes (1997)
Nathoo classification based on chemistry of discoloration

11. Extrinsic discoloration
• Direct staining ( daily acquired )
• Chromogenic bacteria, diet - colour in food
• Indirect extrinsic staining ( chemicals)
• Chlorhexidine and metallic stains
• Beverages – coffee, tea,
• Iron supplements
• Tobacco related
Pre eruptive cause
• Metabolic causes:
• Erythroblastosis fetalis, Congenital porphyria, Congenital
hyperbiliruinaemia
• Inherited causes of discoloration:
• Amelogenesis Imperfecta, Dentinogenesis Imperfecta,
Dentinal dysplasia
• Fluorosis
Intrinsic discoloration
Intra-endodontic procedures
• Irrigants
• Chlorhexidine, Tetracycline, & MTAD
• Intracanal medicament
• Triple antibiotic paste
• Endodontic filling materials
• Silver points
• Gutta percha & Resilon
• Endodontic sealers
• Mineral trioxide aggregate (MTA) - grey MTA
• Metal posts

13. An ideal bleaching material should
• 1. Be safe to use
• 2. Not irritate the gingiva and other oral soft tissues
• 3. Not cause enamel loss, postoperative sensitivity,
or cervical resorption
• 4. Produce the effect faster in a short duration of
time
• 5. Be easily removed from the tooth surface after
producing the desired effect and
• 6. Be stable on storage.
• Hydrogen peroxide
• Carbamide peroxide
• Sodium perborate
• McInnes solution & Modified McInnes
solution
• Over-the-counter (OTC) agents
Commonly
used:
BLEACHING AGENTS
Peroxides
Surfactants
Abrasives- RDA values
Anti Redeposition agents
Proteases
•RECENT ADVANCES ON CONCEPTS OF TOOTH WHITENING - A REVIEW Miloni Suresh Shah , Dhanraj Ganapathy, International Journal
of Scientific Development and Research May 2021 IJSDR | Volume 6, Issue 5.

14. Patient safety
I GENERATION
Liquid form
II GENERATION
Gel form
III GENERATION
Differ in vehicle
and colour
INTRODUCTION
Greenwall L. Bleaching Techniques in Restorative Dentistry. London: Martin Dunitz, 2001

15. OVER THE COUNTER PRODUCTS
Kugel G. Over-the-counter tooth-whitening systems. Compend Contin Educ Dent. 2003 Apr;24(4A):376-82.

16. Mechanism of Action
• H2O2 - low molecular weight – easily penetrate enamel and dentinal tubules
• Breaks down into water and release perhydroxyl ion and nascent oxygen
• Release oxygen breaks down the double bond of inorganic and organic compounds inside the tubule.
• Perhydroxyl free radicals - degrade highly pigmented carbon rings in the stains to carbon chains
• Free oxygen opens carbon ring of pigment molecule & convert it to colourless hydroxyl compounds
• Thus large macromolecular stain converted to small micromolecular stain molecule.
Hydrogen Peroxide o Concentration between 5 and 35% (30-35% - superoxol)

17. Main Constituents - Carbamide peroxide, Hydrogen peroxide, Sodium hydroxide, Sodium perborate
Thickening agents
• Carbopol (carboxypolymethylene)
• Slow release of oxygen
• Increases viscosity of bleaching agent
• Delays oxygen release rate and has longer time to act
Urea
• Stabilise H2o2, elevate pH of solution
• Anticariogenic effects - minimal
Vehicle – glycerin, glycol, dentifrice
Surfactant and pigments dispertants
Preservatives and flavours
Flouride and potassium nitrate
Composition of commercial Bleaching gels

18. • Pola Office is a hydrogen peroxide based in-office tooth
brightening system
• Neutral pH gel and contains desensitizers to maximize
patient comfort.
• Pola Night – 22% carbamide peroxide gel – syringes –
night tray home bleaching
COMPOSITION:
• Pola Office Liquid
• 35% Hydrogen peroxide
• 65% Water
• Pola Office Powder
• 73.26% Thickeners
• 26.2% Catalysts
• 0.04% Dye
• 0.5% Desensitizing agents
SDI Polaoffice Advanced tooth brightening system

19. CHEMISTRY OF BLEACHING
• The oxidation-reduction reaction that takes place in the bleaching process is called the
REDOX REACTION.
• In the process of bleaching, tooth is considered as the reducing agent and bleaching
material is the oxidizing agent.
• After bleaching, tooth is oxidized i.e. organic pigment of tooth is oxidized and the
bleaching material is reduced.
low molecular weight bleaching agent diffuse through the enamel matrix.
Bleaching agents break the pigmented carbon rings and convert them to carbon chains.
Carbon chains are further broken down to hydroxyl group, amount of light absorbed in reduced.
Hence tooth appears light in color.
Changes in their optical properties causes the perception of a lighter color by human eyes.
• Grossman’s, 14th edition
MECHANISM OF BLEACHING

20. SATURATION POINT
As bleaching proceeds, a point is reached at which only hydrophilic colorless tooth structure exists.
This is the material’s SATURATION POINT.
Clinical significance
• Optimal bleaching achieves maximum whitening, the dentist should know that bleaching must be
stopped at or before the saturation point while over bleaching degrades tooth enamel without
further whitening.
• Bleaching beyond saturation point results in weakening of the enamel, material loss due to tooth
brittleness and increased surface porosity resulting in postoperative sensitivity.

21. FACTORS THAT AFFECT BLEACHING
• Moisture & surface debris
• Hydrogen peroxide concentration
• Shelf life
• Temperature
• pH
• Time
• Sealed environment
• Additives
• Others –age, gender
Grossman’s 14th edition

22. NANO MATERIALS FOR TOOTH BLEACHING
Various nanomaterials and agents of mineralization to reinforce the dental hard tissues (Chieruzzietal,2016,Foong etal
2020,Rokaya 2018)
Hydroxyapatite (HA) ,Bioactive Glass(BG),Amorphous calcim phosphate (ACP) –Skallevoldetal2019
Nanodiamonds –Potential for remineralization ( Najeeb etal 2016
These materials may induce remineralization of enamel surfaces by repairing the microscopic pores and early carious
lesions- Microfractures may heal and make the teeth appear brighter (Browning etal 2012,Pedreira De Freitas 2011)
White spot lesions – ACP
hydrolyzing in to apatite and
sealing the defects ( Khoroushi et
al 2016 )
Combinations of Nano /BG
with nano –HA with Nano ACP.
Increased the elastic modulus
,VHN and fracture toughness.

23. Reactive Oxygen Species (ROS)-Based Nanomaterials
Reaction oxide species (ROS) are also called oxygen free radicals,
Which are byproducts of sites on the mitochondrial complexes I and III of the electron
transmitter chain.
ROS normally include hydroxyl radicals (•OH), hydrogen peroxides (H2O2), and superoxides (O2
•− )
In clinical bleaching, the solution of 30% H2O2 or H2O2/TiO2 combination is commonly used.
Makiko used TiO2 coated with hydroxyapatite and produced a high level of ROS and showed
superior bleaching effects without any change of temperature and pH
• Saita, M.; Kobatashi, K.; Yoshino, F.; Hase, H.; Nonami, T.; Kimoto, K.; Masaichi, C.I. ESR investigation of ROS generated
by H2O2 bleaching with TiO2 coated Hap. Dent. Mater. J. 2012, 31, 458–464.

24. Non Peroxide systems
Mazilu etal 2019 - three unique bleaching gel formulations free of peroxides and
based exclusively on plant extracts
In addition to plant extracts gel also contained HA –oxides and HA-flourine ,Ha –Tio2
. The formulated gel exhibited lower cytotoxicity than the commercial formulation

25. DIA (Digital image analysis –Joiner 2006)
Standard shade guides – Commonly used
• Several draw backs – Subjective
Colorimeters can be used –CIE lab value (Commission Internationale
de I Eclairage )
Analysis systems and digital imagingwith non contact cameras can be
used (Guan etal 2005;Jarad etal 2005)
• By taking pre and post bleaching photos one may measure the CIE
Lab values before and after treatment (Gerlachet al 2000)

26. (1) Vital tooth bleaching
A. Dentist prescribed home bleaching ( Night guard bleach)
B. In-Office bleaching
• Thermocatalytic vital tooth bleaching
• Power Bleaching
• Non thermo catalytic vital tooth bleaching
• Micro-abrasion assisted bleaching
• Laser assisted tooth bleaching
(2) Non-vital tooth bleaching
• Thermo catalytic in office technique
• Walking Bleach Technique
• Modified Walking Bleach (closed chamber)
• Combination Technique/ inside outside bleaching
(3)Over the counter products
TYPES OF BLEACHING

27. The source of heat can be:
• Photoflood lamp
• Polymerization light
• Spirit lamp
• Commercial bleaching units
• Light-heat lamp
• Lasers (Argon and Diode)
Thermocatalytic techniques using heat
Duration of bleaching
• The heat/ light activation should be activated for 20-30 mins
• The treatment time should not exceed 30 minutes of
treatment in each appointment, even if the result is not
satisfactory. (saturation point)
• After removing the heat source, tooth is allowed to cool to
avoid sudden temperature change that can be deleterious to
the pulp (allow the teeth to cool down for at least 5
minutes).
POWER
BLEACHING

28. ACTIVATING LIGHT SOURCES
Non-Laser Light Sources
• conventional ultraviolet (UV) bleaching lights,
• QTH (quartz-tungsten-halogen) lamps,
• Xe-halogen lights,
• LED’s (light emitting diodes),
• PAC (plasma arc) lamps,
• MH (metal halide) lamps
Sulieman M. An overview of bleaching techniques: 3. In-surgery or power bleaching. Dental update. 2005 Mar 2;32(2):101-8.
Rembrandt tooth whitening system
• Plasma arc light ( rembrandt sapphire)
Zoom! Teeth whitening system (Discus Dental)
• Mercury metal halide light - 300-450nm (violet coloration)
Curing lights
• Halogen curing light

29. Laser teeth bleaching
Generation of hydroxyl radicals can be improved with lasers
Dyes used – Rhodamine B, other food grade dyes(violet, blue)
Radicals and anions enter the small pores of enamel surface and
react with long chain of chromophores
(Dahi&Pallesen,2003;Joiner,2006;Minoux and Serfaty ,2008)
Chromophore molecular chain geometry changed by double –bond
conjugation
Resulting shortening of the chains and smaller and capable of
diffusion
This change causes chromophores absortion spectrum to shift
accordingly
Finally the eye perceives this change as the whitening of the tooth
(Joiner 2006 )
Three dental laser wavelengths have been
cleared by the Food and Drug Administration
(FDA) for tooth whitening.
i. Argon Laser – 488 nm
ii. CO2 – 10,600 nm
iii. GaAlAs diode laser – 980 nm (Gallium-
Aluminium-Arsenide)
iv. Photochemical laser whitening – smart
bleach
1996 - Argon and CO2 laser first FDA
approved laser for tooth bleaching

30. KTP Laser (Potassium-Titanyl-Phosphate) is derived from Nd:YAG laser (1064nm) by frequency doubling,
and hence half the wavelength (532nm), which gives the distinctive green color.
Used in the treatment of the toughest tooth
discolorations - tetracycline staining.
KTP laser - complete and irreversible bleaching
of red quinone.
Application of 2 Watts for 30 second increases
the temperature by only 2.2°C
Mechanism
• KTP laser energy absorbed into the Rhodamine B dye
is transferred from the excited molecule into
bleaching gel in form of thermal energy.
• Has less penetration
• KTP laser has all three mechanisms of HP activation
• Photo-thermal + Photo-chemical + Photo-dynamic
Klaric E, Rakic M, Marcius M, Ristic M, Sever I, Tarle Z. Optical effects of experimental light-activated bleaching procedures. Photomed Laser Surg 2014;32:160–16

31. ALTERNATIVES TO LIGHT SOURCES - PLASMA
NAPP –Non thermal atmospheric pressure plasma
The combinational treatment of plasma had not indicated
inflammatory responses as well as thermal damages. NAPP did
not cause histological damage in oral soft tissues during tooth
bleaching.

32.  This technique, reported by Miara in 2000, suggests that the Power bleaching technique can be made more
effective by compressing the gel against the teeth.
COMPRESSIVE BLEACHING TECHNIQUE
Sealing the margin of
the tray with
composite resin.
Ultrasonic technology
• Ultrasonic energy is used to enhance bleaching by placing 6 – 7.5%
hydrogen peroxide gel in upper and lower trays for approximately two
cycles of 5 min each.
• the use of the ultrasonic energy indirectly encourages the production of
more oxygen-free radicals to produce the whitening effect.
• SoniWhite Whitening System (DMDS UK, Canterbury, UK).
Sulieman M. An overview of bleaching techniques: 3. In-surgery or power bleaching. Dent Update 2005;32:101-4, 107-8

33. Micro & macro abrasion
MICRO-ABRASION MACRO-ABRASION
Indicated for extrinsic stains to a
depth of no more than 0.2-0.3mm.
Indicated in deeper stains and
defects which extend beyond
0.4mm of enamel.
It involves both chemical erosion
and physical abrasion of the tooth
surface.
Unlike micro abrasion dissolution of
enamel before physical abrasion is
not the initial step.
Traditionally, this technique involves
the use of 18% HCl and a pumice
paste in a slow speed handpiece
with light pressure.
A 12-fluted round diamond fissure
bur in high speed handpiece with
copious water irrigation is used.

34. Types of Nonvital bleaching
 “walking bleach”
 Thermo catalytic technique
 Inside / outside bleaching
 Combined bleaching
Inside/Outside Bleaching Technique
 Shape from facial view is bobsled tunnel shaped
 Shape from proximal view is ski slope shaped
COMPLETE DENTAL BLEACHING by Ronald E. Goldstein & David A. Garber
Barrier transfer technique
• Internal level of barrier – 1mm incisal to external probing of epithelial
attachment - verified radiographically.

35. Whiteness HP Maxx
• Hydrogen peroxide at 35%
• Special dyes - absorbent barrier - intense red to green
Opalescence Boost PF 40%
 The first syringe - contains 40 % hydrogen peroxide
 The second syringe - contains fluoride and potassium nitrate
(PF)
Opalescence Xtra (Ultradent)
 Carotene mixed within the bleaching agent - conversion of light
into heat
LASE PEROXIDE SENSY
LASE PEROXIDE LITE
Nanotechnology and the lowest H2O2 conc: 15% with neutral Ph
NITE WHITE ACP
• Amorphous calcium phosphate (ACP) - remineralize teeth

36. SIDE EFFECTS OF BLEACHING
Transient tooth sensitivity and irritation to soft tissues (Federation 2013)
occurs in 15% -78% of patients ,clinical studies assessing risks is lacking
•Dahl JE, Pallesen U. Tooth Bleaching—a Critical Review of the Biological Aspects. Critical
Reviews in Oral Biology & Medicine. 2003;14(4):292-304.
They may compromise the structure of enamel by altering it at a microlevel
(Mairaet al 2008)
Intrinsic bleaching – weakening the remaining tooth structure
Increased risk of tooth fracture
Increased risk of external cervical root resorption (Tredwin etal 2006 )
Allergy and cytotoxicity -

37. HP leads to genotoxic changes among cells in culture
and these unwanted effects are reduced when
metabolizing enzymes were present –Dahl 2003
Possible role of HP as tumour promoter in animal
studies – local contact adverse effects
10% Hp showed least infiltration and other tissue
changes
Decreased time of exposure , protecting the soft tissues
by liquid dam and increased use of remineralizing
agents may help to reduce the tissue damages

38. CONCENTRATION OF PEROXIDES
When the concentration of HP exceeds 30% (Dahl and Pallessen 2003
Reduces the microhardness of dental hard tissue,weakens the
mechanical strength of dentin(Chng et al 2002)
Heat (Thermo catalytic technique ) increases the risk of cervical root
resorption -Friedman etal 1998
Addition of flouride or HA has been reported to reduce or even prevent
the mineral loss from enamel during bleaching ( Najeebetal 2019,
Khurshid etal( 2015)

39. Regulations and recommendations for bleaching products
Classified as cosmetic
substances ,strictly
regulated in European
union –EU
Dental bleaching is considered to
be the treatment of cosmetic
character rather than therapeutic
(European commission , manual
on Border line and classification
in the community regulatory
frame work for medical Devices .
2017)
Dec 1 ,2010 ,Sodium
perborate in all cosmetic
products was banned –
Classified as carcinogenic
,mutagenic ,or toxic for
reproduction

40. REGULATIONS
Concentrations higher than 6% HP has been banned
Bleaching concentrations between 0.1 % and 6% HP can be
sold to dentists only
OTC PRODUCTS ARE NOT ALLOWED TO EXCEED 0.1% CONC
.OF HP ( Eurpean commission of regulation on 30th Nov 2019)
FDA has highlighted clinical issues regarding the use of
bleaching agents (2013)

41. • Rehydration and application of an antiseptic ointment (Barghi, 1998)
• Vitamin E capsules - a powerful antioxidant
• Effective protection of gingiva and mucosa with good isolation
mucosal ulcers or
chemical burns
Mohammed Q. Alqahtani. Tooth-bleaching procedures and their controversial effects: A literature review. The Saudi Dental Journal
(2014) 26, 33–46
MUCOSAL DAMAGE

42. TOOTH SENSITIVITY
Desensitization with neutral
sodium fluoride
3% potassium nitrate gel
(ULTRADENT)
Paste containing amorphous
calcium phosphate
(Recaldent)
Kwon SR, Ko SH, Greenwall L. Tooth Whitening in Esthetic Dentistry, Principles and Techniques. Quintessence Publishing Co. Ltd.2008.

43. BLEACHING EFFECT ON TOOTH SURFACE MORPHOLOGY
Little changes in enamel surface
texture (McGukin et al 1992)
Shallow depressions, increased
porosity, slight erosions- normalize
through salivary remineralisation
Untreated enamel
Acid etched
10% carbamide peroxide

44. Increased surface hardness (Alqahtani. 2013), Increased surface
roughening & etching (Mor et al. 1998).
Softening of composite resins Lima et al. 2008).
Affects marginal seal Thomas Attin et al 2004
Increased micro leakage (Polydorou et al. 2009; White et al. 2008)
Colour change in composites
• More changes in microfilled composite resin (Hubbezoglu et al., 2008).
• Bleached composite resins stain more easily (Yu et al. 2009).
Mohammed Q. Alqahtani. Tooth-bleaching procedures and their controversial effects: A literature review. The Saudi Dental Journal (2014) 26, 33–46
BLEACHING EFFECT ON COMPOSITE RESTORATION

45. Antioxidant therapy
• Ascorbic acid and proanthocyanidin
• Lai et al. (2002) - sodium ascorbate can immediately reverse the compromised bond strength
• powerful antioxidant used for removal of residual oxygen after bleaching.
• Application of 10% sodium ascorbate solution for 10 mins - alternative to the delayed bonding procedure after
bleaching.
• Kaya and Turkun, 2003; Kimyai and Valizadeh, 2006, 2008; Turkun et al., 2009, Feiz et al. (2011), Dabas et al. (2011)
Mohammed Q. Alqahtani. Tooth-bleaching procedures and their controversial effects: A literature review. The Saudi Dental Journal (2014) 26, 33–46
Techniques to solve this clinical problem
•Delay upto one week postbleaching
•Remove the superficial layer of enamel
•Kalili et al. and Sung et al. - use of adhesives containing organic solvents.
•Use of acetone based adhesive system - Niat et al. (2012)
Decrease in bond strength
immediately after bleaching
(Titley 1988, stokes et al. 1992, Garcia-
Godoy 1993, Dishman et al. 1994, Ben-
amar et al. 1995)

46. RESIN INFILTRATION
47
Torres CR, Borges AB. Color masking of developmental enamel defects: a case series. Operative dentistry. 2015 Jan;40(1):25-33.
Horuztepe SA, Baseren M. Effect of resin infiltration on the color and microhardness of bleached white‐spot lesions in bovine enamel (an in vitro study). Journal of Esthetic
and Restorative Dentistry. 2017 Sep;29(5):378-85.
ICON Etch- 2min
ICON infiltrant- 3 min, light cure 40 sec
ICON Dry- 30 sec
Bleaching treatment before resin
infiltration -significant
color alteration
Increases the microhardness of
bleached and unbleached WSLs
Bleaching treatments negatively
influence the penetration of
infiltrants

47. There is such a wide range of whitening options, the average teeth bleaching results can last anywhere from
six months to three years. In most cases, however, people tend to have results that last about one year.
(Dr Quartano,Magnolia Dental , Feb. 12 ,2020)
Regression of color change is a common problem both in vital and nonvital bleaching, Retreatment is
necessary in many cases, usually after 1–3 years,
Stephen Burrows, Dental Update VOL. 36, NO. 9, Prosthodontics ,2009. A Review of the Efficacy of
Tooth Bleaching
Leonard et al 1999 evaluated the color stability after 54
months of tetracycline stained teeth treated with 10%
carbamide peroxide – Remained stable for 54 months
Longest post treatment clinical study published
• Leonard RH ,HaywoodVB ,etal , Eagle JC 1999- Night guard Vital
bleaching of tetracycline stained teeth ; 54 months post treatment .J
Esthet Dent 11(5);265-77

48. Proper Diagnosis and treatment planning for various type of discolorations
Use 6% and below concentration HP gels for bleaching to minimize tissue damage
Use Remineralizing agents for repair to occur and the bleaching results are sustained
Nano materials based bleaching agents are more useful in sustaining the results.
Please keep in mind bleaching is a cosmetic procedure –According to EU and our Govt also attracts GST of 18%
Encourage Non HP bleaching agents ,Herbal plant extracts may be of use

49. 1. A. Watts and M. Addy, Tooth discolouration and staining: a review of the literature. British Dental Journal
Volume 190 No.6 March 24 2001
2. Ronald E. Goldstein’s Esthetics in Dentistry. Third edition
3. Cohen’s Pathways of the Pulp. Twelfth edition
4. Joshi SB. An overview of vital teeth bleaching. J Interdiscip Dentistry 2016;6:3-13.
5. Overview of in-office bleaching of vital teeth, Hegde Mithra N et al, IRJP 2012, 3 (11)
6. Mohammed Q. Alqahtani. Tooth-bleaching procedures and their controversial effects: A literature review.
The Saudi Dental Journal (2014) 26, 33–46
7. Croll T. Enamel Microabrasion. Chicago: Quin- tessence, 1991:27-60.
8. Grossman’s Endodontic Practice 14th Edition
9. Sulieman M. An overview of bleaching techniques: 1. History, chemistry, safety and legal aspects. Dental
update. 2004 Dec 2;31(10):608-16.
10. Sulieman M. An overview of bleaching techniques: 2. Night Guard Vital Bleaching and non-vital bleaching.
Dental update. 2005 Jan 2;32(1):39-46.

50. 11. Sulieman M. An overview of bleaching techniques: 3. In-surgery or power bleaching. Dental update.
2005 Mar 2;32(2):101-8.
12. Kihn PW. Vital tooth whitening. Dental Clinics of North America. 2007 Apr 1;51(2):319-31.
13. Kugel G. Over-the-counter tooth-whitening systems. Compend Contin Educ Dent. 2003
Apr;24(4A):376-82.
14. Buchalla W, Attin T. External bleaching therapy with activation by heat, light or laser--a systematic
review. Dent Mater. 2007 May;23(5):586-96.
14. Torres CR, Borges AB. Color masking of developmental enamel defects: a case series. Operative
dentistry. 2015 Jan;40(1):25-33.
15. Horuztepe SA, Baseren M. Effect of resin infiltration on the color and microhardness of bleached
white‐spot lesions in bovine enamel (an in vitro study). Journal of Esthetic and Restorative Dentistry.
2017 Sep;29(5):378-85.
16. Attin T, Hannig C, Wiegand A, Attin R. Effect of bleaching on restorative materials and restorations-
a systematic review. Dent Mater 2004. 20:852-61.
17. Dahl JE, Pallesen U. Tooth bleaching- a critical review of the biological aspects. Crit Rev Oral Bio
Med 2003;14:292-304
18. Zimmerli B, Jeger F, Lussi A. Bleaching of nonvital teeth. A clinically relevant literature review.
Schweiz Monatsschr Zahnmed. 2010;120(4):306-20.

51. drsadasiva2@gmail.com

52. 9791096355
Chettinad Dental College
and Research institute
Chennai
drsadasiva2@gmail.com