2. Dental Bleaching
By Students
Mohammed Sa’ad Al Nuaimi
Abeer Farman Al Dulayme
Dhuha Wael Al Janaby
Duaa’ Sa’ad Al Zubaide
Supervised by
Dr. Zena Tariq Al Ani
BDS. MSC. Conservative Department
3. Acknowledgement
We are honored to dedicate this scientific research to :
His highness minster of the higher education and scientific research
The dean of the college Dr. Ali Za’lan Ne’ma
The Head of the Dentistry Department Dr. Mohammed Al yaserie
The Head of conservative department Dr. Zena Tariq Al ani
The senior of the conservative clinic Dr. Hadeel Kareem Hamza
And our beloved families.
4. Abstract
Personal appearance is important in today’s society. Many products and
procedures, including tooth whitening, are being marketed to the public as a
method for enhancing personal appearance. People frequently ask dental
professionals whether tooth whitening is effective and whether it would be
appropriate treatment for them. In order to field the public’s questions and
promote informed choices, dentist must be knowledgeable about tooth
whitening products and procedures.
A Medline search over a 25-year period was conducted to locate studies about
the efficacy, effects and biological safety of tooth whitening products and
procedures. The search resulted in approximately 60 articles. Additional
articles were obtained through article references. The objective of the
research was to prepare a literature review on tooth whitening.
5. The literature revealed that teeth can be bleached approximately two shades
but a second follow-up treatment is usually required after one to three years.
In-office and at-home bleaching techniques were studied. Bleaching materials
were found to adversely affect dental hard tissues. Some evidence was
provided to support the view that short-terms of tooth whitening on tooth
pulps appear to be reversible Long-term effects of bleaching agents on hard
and soft tissues remain unknown. Evidence shows there is a reduction in
enamel-composite resin bond strength in teeth treated with peroxide agents
though the clinical significance of this bond reduction is not known. Safety
issues concerning the impact of peroxide agents on human oral mucosal
antioxidant defense mechanisms were identified.
The writers’ research found little consensus in much of the research. A
number of significant areas of concern have not yet been thoroughly
investigated. Long-term scientific human studies are recommended to address
the unanswered questions about the efficacy, effects and biological safety of
tooth whitening.
6. List of Subjects
Acknowledgement
Abstract
Introduction
Causes of Tooth Discoloration
The mechanism of action of bleaching
Factors affect tooth bleaching
Types of dental bleaching
Non-vital bleaching
Vital bleaching or home bleaching
Light-accelerated bleaching
Natural methods
Bleaching Materials
Safety Concerns with Tooth Bleaching Materials
Summary
7. List of Figures
Fig 1 A Stained teeth with smocking habit patient
B After bleaching process although the use of ceramic alternative to improve lateral
incisor
C Stained teeth with medications induced tooth discoloration
D After a combination of home and office tooth bleaching the result is brighter teeth.
Fig 2 Common oxidation processes associated with bleaching teeth. The saturation point at
which the optimal amount of bleaching has occurred is located in the middle of the
diagram. 6
Fig 3 pre- and postoperative colour of a darkened nonvital
tooth following trauma. The appearance improved greatly after 2 weeks.
Fig 4 White opaque lesions on the two central incisors
8. List of Tables
Table 1 : Causes of tooth discoloration
List of Abbreviation
OTC Over the counter
FDA U.S. Food and Drug Administration
ADA American Dental Association
MIH melanotropin release-inhibiting hormone
9. Introduction
Over the past two decades, tooth whitening or bleaching has become one of the
most popular esthetic dental treatments (Note: this paper uses the terms
"whitening" and “bleaching," interchangeably). Since the 1800s, the initial focus of
dentists in this area was on in-office bleaching of non-vital teeth that had
discolored as a result of trauma to the tooth or from endodontic treatment. By the
late 1980s, the field of tooth whitening dramatically changed with the
development of dentist-prescribed, home-applied bleaching (tray bleaching) and
other products and techniques for vital tooth bleaching that could be applied both
in the dental office and at home.
The tooth whitening market has evolved into four categories: professionally
applied (in the dental office); dentist-prescribed/dispensed (patient home-use);
consumer-purchased/over-the-counter (OTC) (applied by patients); and other non-
dental options. Additionally, dentist-dispensed bleaching materials are sometimes
used at home after dental office bleaching to maintain or improve whitening
results.
10. Consumer whitening products available today for home use include gels,
rinses, chewing gums, toothpastes, paint-on films and strips. The latest tooth
whitening trend is the availability of whitening treatments or kits in non-
dental retail settings, such as mall kiosks, salons, spas and, more recently,
aboard passenger cruise ships. Non-dental whitening venues have come under
scrutiny in several states and jurisdictions, resulting in actions to reserve the
delivery of this service to dentists or appropriately supervised allied dental
personnel.
Current tooth bleaching materials are based primarily on either hydrogen
peroxide or carbamide peroxide. Both may change the inherent color of the
teeth, but have different considerations for safety and efficacy. In general,
most in-office and dentist-prescribed, at-home bleaching techniques have
been shown to be effective, although results may vary depending on such
factors as type of stain, age of patient, concentration of the active agent,
and treatment time and frequency. However, concerns have remained about
the long-term safety of unsupervised bleaching procedures, due to abuse and
possible undiagnosed or underlying oral health problems.
11. Although published studies tend to suggest that bleaching is a relatively safe
procedure, investigators continue to report adverse effects on hard tissue,
soft tissue, and restorative materials.1-3 The rate of adverse events from use
or abuse of home-use OTC products is also unclear because consumers rarely
report problems through the U.S. Food and Drug Administration (FDA)
Medwatch system. Based on these factors, the American Dental Association
(ADA) has advised patients to consult with their dentists to determine the
most appropriate whitening treatment, particularly for those with tooth
sensitivity, dental restorations, extremely dark stains, and single dark teeth.4
Additionally, a patient’s tooth discoloration may be caused by a specific
problem that either will not be affected by whitening agents and/or may be a
sign of a disease or condition that requires dental therapy.
12. Causes of Tooth Discoloration
A child's deciduous teeth are generally whiter than the adult teeth that
follow. As a person ages the adult teeth often become darker due to changes
in the mineral structure of the tooth, as the enamel becomes less porous and
phosphate-deficient. Teeth can become stained by bacterial pigments,
smoking, food-goods and vegetables rich with carotenoids or xanthonoids.
Certain antibacterial medications (like tetracycline) can cause teeth stains or
a reduction in the brilliance of the enamel. Ingesting colored liquids like
coffee, tea, and red wine can discolor teeth.
13.
14.
15. The mechanism of action of bleaching
It is also unclear. Bleaching is an oxidation reaction. The enamel to be
bleached donates electrons to the bleaching agent.2 Ten per cent carbamide
peroxide breaks down to 3% hydrogen peroxide and 7% urea. The hydrogen
peroxide metabolizes into water and free radicals of oxygen. These free
radicals possess a single electron, which is thought to combine with the
chromagens to decolourize or solubize them. 5
18. Types of dental bleaching
There are two types of bleaching:
vital
Non-vital
Both clinical techniques rely upon the action of hydrogen peroxide to change the
appearance of the teeth.
19. NON-VITAL BLEACHING
Case Selection
Non-vital teeth that have discoloured as a result of trauma can be successfully
bleached, but those with other intrinsic stains such as amalgam or remineralized
lesions will be more resistant to colour change. Teeth with minor restorations on
the buccal surface – or, ideally, those with only an access cavity present – are the
most successfully bleached. Teeth with extensive restorations are usually more
effectively treated with crowns .Ideally, the shade of the unbleached tooth
should be recorded using a shade guide or clinical photographs before attempting
to bleach it.
20. Clinical Technique
Nutting and Poe8 advocated placing a slurry of sodium perborate and hydrogen peroxide in
the access chamber of nonvital teeth, provided that an adequate seal is present both
apically and coronally.
They called this the .walking bleach. technique. It is essential (in the view of the author) to
ensure that the root treatment is asymptomatic, free from periapical changes and has a
good obturation with gutta-percha. Once the root treatment has been completed all the
remaining gutta-percha should be removed to below the level of the gingival margin within
the radicular canals. It is also important to ensure that the buccal surface of the access
cavity is free of restorative material such as composite; although theoretically the
bleaching agent can permeate around or through the material, it is more convenient to
ensure that the material has been removed at the start. A glass ionomer, zinc phosphate or
composite lining should be placed in the radicular part of the root canal below the gingival
margin to seal the canal from the bleaching agent. Some practitioners have advocated
etching the internal surface of the cavity with a proprietary etchant.
However, Casey and co-workers reported that etching made no difference to the success of
bleaching.19 Once the access cavity is clear, 100- volume hydrogen peroxide (obtainable
from chemists or hospital pharmacists) is mixed with powdered sodium perborate to
produce a damp slurry. The slurry is carried to the tooth, surrounded by a rubber dam, and
placed so that it partially fills the pulpal chamber. A cotton wool pellet is then placed on
top of the slurry and the access cavity sealed with temporary cement (this can be zinc
oxide eugenol, polycarbonate cement, glass ionomer or composite). The patient is reviewed
within 2 weeks and the process repeated until the colour is improved to the patient.s
satisfaction. Often the site that is most resistant to bleaching is around the cervical margin
and onto the root surface. Figure 3 shows the pre- and postoperative colour of a darkened
nonvital tooth following trauma. The appearance improved greatly after 2 weeks.
21.
22. VITAL BLEACHING OR HOME BLEACHING
Case Selection
Unlike non-vital bleaching, most cases of vital bleaching involve more than one tooth. Darkening of teeth
caused by ageing is possibly one of the more common forms of discoloration of teeth and is successfully
treated with vital bleaching. Tetracycline-stained teeth are not as common as they were 10-15 years ago
as the medical and dental profession are now fully aware of the implications of prescribing drugs that
cause staining during tooth development. However ,tetracycline stain can be found in people
born outside the UK. The severity of tetracycline stains can vary from a brown-yellow coloration, which
can respond to bleaching, to a blue-black ,which traditionally is more resistant .Fluorosis is more
commonly found within the UK and can present as white or brown speckles or patches on teeth ( Figure 4).
The brown discoloration can be removed by bleaching but the white opacities are more resistant, although
bleaching can in some situations reduce the brilliance of the white by merging the colour with the
surrounding teeth. More localized discoloration on teeth can occur in any severe childhood illness and may
also cause changes in the shape of the teeth due to disruption in the tooth development .For successful
bleaching, case selection is extremely important. People perceive colour differently and what appears
acceptable to one person may not be to someone else. It is also important to attempt to distinguish with
what aspect of
a tooth a patient is dissatisfied. It may be that the relatively darker area around the cervical-gingival
margin of a canine is unacceptable to a patient, but once this is explained as a natural phenomenon their
concern may be alleviated and treatment becomes unnecessary. Incidentally, this area is also more
resistant to changes in
tooth colour by bleaching.
23. Fig. 4 : White opaque lesions on the two
central incisors. These could be treated by
bleaching but may be more responsive to acid
abrasion or enamel biopsy techniques followed
by localized composite restorations
24. Clinical Technique
The most commonly referenced vital bleaching products are those containing a 10%
solution of carbamide peroxide .This material breaks down to form a 3% solution of
hydrogen peroxide and urea .The carbamide peroxide is usually delivered in a viscous
gel, which is applied closely to teeth via a custommade vacuum-formed appliance. The
appliance should be well contoured to the gingival margins to reduce the potential for
irritation of the gingival tissues and spaced over the teeth that are to be bleached. This
spacer is applied to the working model on the teeth that will be bleached and can be a
proprietary material or common laboratory product such as die relief or nail varnish.
The
thickness of the appliance should be around 2 mm – not so thick that it causes
discomfort .In a study by Frazier and Haywood,7 81% of dental schools taught the use
of reservoirs and scallops around the gingival margin in the design of the bleaching
appliance, whilst only 13% used trays without reservoirs, indicating the popularity of
the former technique .Home bleaching products are most successful if the patient
applies the
material into the trays for 6-8 hours a day (often overnight) and usually over a period of
3-4 weeks, but different products vary. Frazier and Haywood reported that bleaching
was most commonly successful after 2-4 weeks.7 For more intense stains, such as that
found with tetracycline, it may take between 3 and 6 months to reach a successful
result. If patients do not add the bleaching agent regularly to the tray there is
insufficient time for the hydrogen peroxide to work and they become disappointed,
which becomes a
vicious circle and success is unlikely
25. Light-accelerated bleaching
Power or light-accelerated bleaching, sometimes colloquially referred to as laser
bleaching (a common misconception since lasers are an older technology that was
used before current technologies were developed), uses light energy to accelerate
the process of bleaching in a dental office. Different types of energy can be used
in this procedure, with the most common being halogen, LED, or plasma arc.
Clinical trials have demonstrated that among these three options, halogen light is
the best source for producing optimal treatment results.[9] The ideal source of
energy should be high energy to excite the peroxide molecules without
overheating the pulp of the tooth.[10] Lights are typically within the blue light
spectrum as this has been found to contain the most effective wavelengths for
initiating the hydrogen peroxide reaction. A power bleaching treatment typically
involves isolation of soft tissue with a resin-based, light-curable barrier,
application of a professional dental-grade hydrogen peroxide whitening gel (25-
38% hydrogen peroxide), and exposure to the light source for 6–15 minutes. Recent
technical advances have minimized heat and ultraviolet emissions, allowing for a
shorter patient preparation procedure. Most power teeth whitening treatments
can be done in approximately 30 minutes to one hour, in a single visit to a dental
physician.
26. Natural methods
There are many popular natural ways to whiten one's teeth. Some natural teeth
whitening methods can be very gentle on the teeth, while others can lead to
enamel damage. One efficient type of natural teeth bleaching is through the use
of malic acid.[11][12] One simple way of natural tooth bleaching is by applying the
pulp of crushed strawberries (which contains malic acid) to the teeth and leaving
it there for five minutes. Remains of strawberry pulp can be removed by flossing
the teeth. Another way is by 'gently and circularly' brushing one's teeth with some
baking soda (an 'abrasive' teeth whitener) using a soft toothbrush. Malic acid and
sodium bicarbonate are effective whitening treatments but should be used
sparingly as both methods are not too gentle on the teeth. They could lead to
enamel damage if used indiscriminately (i.e., more than a couple of times a week
or so).
Apples, celery and carrots support and help whitening teeth,[13] as they act like
natural stain removers by increasing saliva production (the mouth's self-cleaning
agent) and scrub the teeth clean. They help maintain a fresh breath by killing
bacteria that produces halitosis. The juice of apples, especially green apples,
contains malic acid.
A whitening toothpaste can be made by mixing one part baking soda with two
parts of hydrogen peroxide. While some cheaper commercial whitening
toothpastes have baking soda (sodium bicarbonate) as the whitening ingredient, it
is not recommended to use a baking soda-based toothpaste daily for long periods
Typical whitening gels use some form of peroxide as their active ingredient, and
peroxides have no ability to dissolve the proteins that stain the porous surfaces of
teeth.
27. Bleaching Materials
The active ingredient in tooth bleaching materials is per- oxide compounds.
While currently a variety of bleaching
materialsareavailable,themostcommonlyusedperoxide compounds are
hydrogen peroxide, sodium perborate, and carbamide peroxide. Bleaching
materials for extra- coronalbleachingmainlycontainhydrogenperoxideand
carbamide peroxide, whereas sodium perborate is used for intracoronal
bleaching. Both sodium perborate and carbamide peroxide decompose to
release hydrogen peroxide in an aqueous medium.
28. Hydrogen Peroxide
Hydrogen peroxide (H2O2) is used in both in-office and at-home bleaching
materials. In-office bleaching materials contain high concentrations of H2O2
(typically 25% to 38%), while the H2O2 concentration in at-home bleaching
products usually range from 3% to 7.5%; however, there have been products
containing up to 14% H2O2 for home use by patients. H2O2 at high
concentration, such as those in the inoffice bleaching materials, is caustic
and burns tissues on contact. These materials must be handled with care to
avoid their contact with tissues during the handling and bleaching treatment.
29. Sodium Perborate
Sodium perborate (NaBO3) is available in powdered form or as various
commercial preparations. When fresh, it contains about 95% perborate,
corresponding to 9.9% of the available oxygen. Sodium perborate is stable
when dry. In the presence of acid, warm air, or water, however, it decomposes
to form sodium metaborate, H2O2, and nascent oxygen. Three types of
sodium perborate preparations are available: monohydrate, trihydrate, and
tetrahydrate. They differ in oxygen content that determines their bleaching
efficacy. Commonly used sodium perborate preparations are alkaline, and
their pH depends on the amount of H2O2 released and the residual sodium
metaborate.
Sodium perborate is more easily controlled and is safer than concentrated
H2O2. Therefore, it is the material of choice in most intracoronal bleaching
procedures.
30. Carbamide Peroxide
Carbamide peroxide (CH6N2O3), also known as urea hydrogen peroxide, exists
in the form of white crystals or as a crystallized powder containing
approximately 35% H2O2. It forms H2O2 and urea in aqueous solution. It is
mostly used in home-use bleaching materials with concentrations ranging
from 10 to 30% (equivalent to approximately 3.5% to 8.6% H2O2); however,
those containing 10% carbamide peroxide appear to be the most common.
Bleaching preparations containing carbamide peroxide usually also include
glycerine or propylene glycol, sodium stannate, phosphoric or citric acid, and
flavor additives. In some preparations, carbopol, a watersoluble polyacrylic
acid polymer, is added as a thickening agent. Carbopol also prolongs the
release of active peroxide and improves shelf life.
31. Safety Concerns with Tooth Bleaching
Materials
Concerns regarding the safety of all bleaching treatments and products have long existed, but were
heightened since the introduction of at-home bleaching.14-15 Discussions in this section focus on
peroxides and their use as active ingredients in tooth bleaching materials. Important concerns
related to patient examination and diagnoses are addressed elsewhere in this report.
A variety of peroxide compounds, including carbamide peroxide, hydrogen peroxide, sodium
perborate and calcium peroxide, have been used as active ingredients for bleaching materials;
however, essentially all extracoronal bleaching materials currently available for whitening of vital
teeth in the United States contain carbamide peroxide and/or hydrogen peroxide. Recently,
products containing chlorine dioxide were introduced in the United Kingdom, but there is no
evidence that tooth bleaching products using chlorine dioxide as the active ingredient are safer than
peroxide-based materials. In fact, safety concerns have been documented with chlorine dioxide and
its use for tooth bleaching treatment due to the low pH of the material and resultant tooth
etching.16
Most OTC bleaching products are hydrogen peroxide-based, although some contain carbamide
peroxide. Carbamide peroxide decomposes to release hydrogen peroxide in an aqueous medium: ten
percent carbamide peroxide yields roughly 3.5% hydrogen peroxide. In-office bleaching materials
contain high hydrogen peroxide concentrations (typically 15-38%), while the hydrogen peroxide
content in at-home bleaching products usually ranges from 3% to 10%; however, there have been
home-use products containing up to 15% hydrogen peroxide.
32. Safety issues have been raised regarding the effects of bleaching on the tooth
structure, pulp tissues, and the mucosal tissues of the mouth, as well as systemic
ingestion. Regarding mucosal tissues, safety concerns relate to the potential
toxicological effects of free radicals produced by the peroxides used in bleaching
products. Free radicals are known to be capable of reacting with proteins, lipids
and nucleic acids, causing cellular damage. Because of the potential of hydrogen
peroxide to interact with DNA, concerns with carcinogenicity and co-
carcinogenicity of hydrogen peroxide have been raised, although these concerns so
far have not been substantiated through research.14,17,18 However, studies have
shown that hydrogen peroxide is an irritant and also cytotoxic. It is known that at
concentrations of 10% hydrogen peroxide or higher,
the chemical is potentially corrosive to mucous membranes or skin, and can cause
a burning sensation and tissue damage.14,19,20 The amount of products applied
during office bleaching treatment and other formulation variables can change the
potential to cause damage. However, severe mucosal damage can occur if gingival
protection is inadequate with high strength tooth whitening products. Clinical
studies have also observed a higher prevalence of gingival irritation in patients
using bleaching materials with higher peroxide concentrations.21,22
33. Data accumulated over the last 20 years, including some long-term clinical study follow up23, 24; indicate
no significant, long-term oral or systemic health risks associated with professional at-home tooth bleaching
materials containing 10% carbamide peroxide (3.5% hydrogen peroxide). However, these data were
collected from studies which include examinations by dental professionals, and there is no safety evidence
on bleaching materials that do not involve such examinations by dental professionals, regardless of
hydrogen peroxide concentration or application venue. Additionally, consumers are not generally aware of
how to report adverse events through FDA’s Medwatch system. If a licensed dental professional is not
consulted when patients use OTC bleaching products, adverse effects due to product abuse may go
unreported.
Regarding hard tissues, transient mild to moderate tooth sensitivity can occur in up to two-thirds of users
during early stages of bleaching treatment.25 Sensitivity is generally related to the peroxide concentration
of the material and the contact time; it is most likely the result of the easy passage of the peroxide
through intact enamel and dentin to the pulp during a five- to 15-minute exposure interval. However, there
have been no reported long-term adverse pulpal sequellae when proper techniques are employed. The
incidence and severity of tooth sensitivity may depend on the quality of the bleaching material, the
techniques used, and an individual’s response to the bleaching treatment methods and materials. To date,
there is little published evidence documenting adverse effects of dentist-monitored, at-home whiteners on
enamel, but two clinical cases of significant enamel damage have been reported, apparently associated
with the use of OTC whitening products.26,27 This damage may be related to the low pH of the products
and/or overuse.
In vitro studies suggest that dental restorative materials may be affected by tooth bleaching agents.28
These findings relate to possible physical and/or chemical changes in the materials, such as increased
surface roughness, crack development, marginal breakdown, release of metallic ions, and decreases in
tooth-to-restoration bond strength. Such findings have not appeared in clinical reports or studies.
To address the safety of bleaching materials, the ADA convened a panel of experts in 1993. The ADA
subsequently published its first set of guidelines for evaluating peroxide-containing tooth whiteners.29
These guidelines have been revised periodically.
In March 2005, the European Scientific Committee on Consumer Products (SCCP) concluded the following:
―The proper use of tooth whitening products containing >0.1 to 6.0% hydrogen peroxide (or equivalent for
hydrogen peroxide-releasing substances) is considered safe after consultation with and approval of the
consumer's dentist.
34. SCCP, in January 2008, again recommended that up to 6% hydrogen peroxide is a safe limit to
use for at-home tooth bleaching; however, it did not recommend use of such products without
dental consultation.30
In summary, available data indicate that extracoronal bleaching treatment in the dental office
or at home may cause short-term tooth sensitivity and/or gingival irritation. More severe
mucosal damage is possible with high hydrogen peroxide concentrations. While available
evidence supports the safety of using bleaching materials of 10% carbamide peroxide (3.5%
hydrogen peroxide) by dental professionals, there are concerns with the use of at-home
bleaching materials with high hydrogen peroxide concentrations. Studies designed specifically
to assess the long-term safety of high hydrogen peroxide concentration in at-home bleaching
materials are needed, especially for repeated use of these products. There appears to be
insufficient evidence to support unsupervised use of peroxide-based bleaching materials.
Similar to other dental and medical interventions, questions have been raised about the safety
of tooth whitening treatments during pregnancy. In the absence of such evidence, clinicians
may consider recommending that tooth whitening be deferred during pregnancy.
The safety of tooth bleaching for children and adolescents is also a consideration. More
research is needed to establish appropriate use and limitations for these patients. However,
bleaching is a conservative approach compared with restorative options when tooth
discoloration causes significant concern. If possible, delaying treatment until after permanent
teeth have erupted is recommended, as is use of a custom-fabricated bleaching tray to limit
the amount of bleaching gel.31 Close professional and parental/guardian supervision are
needed to maximize benefits and minimize adverse effects and overuse.
35. Summary
Tooth bleaching is one of the most conservative and cost-effective dental
treatments to improve or enhance a person’s smile. However, tooth bleaching
is not risk-free and only limited long-term clinical data are available on the
side effects of tooth bleaching. Accordingly, tooth bleaching is best performed
under professional supervision and following a pre-treatment dental
examination and diagnosis.
In consultation with the patient, the most appropriate bleaching treatment
option(s) may be selected and recommended based on the patient’s lifestyle,
financial considerations, and oral health. Patients considering OTC products
should have a dental examination, and should be reminded that they may
unknowingly purchase products that may have little or no beneficial effect on
the color of their teeth and may also have the potential to cause harm.
36. References
1- 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.
2- Goldstein, R.E.: Esthetic dentistry — a health service. J Dent Res 3: pp. 641–642, 1993
3- Goldberg M, Grootveld M, Lynch E. Undesirable and adverse effects of tooth-whitening products: a review.
Clin Oral Invest 2010;14:1-10.
4- American Dental Association Council on Scientific Affairs. Statement on the effectiveness of tooth whitening
products. February 2008. Retrieved August 14, 2009, from http://www.ada.org/1902.aspx
5- Nathoo, S.A.: The chemistry and mechanisms of extrinsic and intrinsic discoloration. JADA 128: pp. 6S–9S,
1997.
6- Tooth lighting ADEPT Robert 1991:2(1):1-24.)
7- Frazier KB, Haywood VB. Teaching nightguard bleaching and other tooth-whitening procedures in North
American Dental Schools. J Dent Educ 2000; 64: 356-357.
8- Nutting EB, Poe GS. Chemical bleaching of discolored endodontically treated teeth. Dent Clin North Am 1967;
Nov: 655-662.
9- Patel, A; Luca, C; Millar, BJ (2008). "An in vitro comparison of tooth whitening techniques on natural tooth
colour". British dental journal 204 (9): E15; discussion 516–7. doi:10.1038/sj.bdj.2008.291. PMID 18408707.
10- "Accepted Over-the-Counter Products". Retrieved 2010-07-05.
11- "How to Whiten Your Teeth Naturally". February 21, 2008. Retrieved 12-02-2012.
12- "Foods That Whiten Teeth Naturally". Retrieved 12-02-2012.
13- "How to Whiten Your Teeth Naturally #2". May 20, 2011. Retrieved 12-02-2012.
14- Li Y. Biological properties of peroxide-containing tooth whiteners. Food and Chem Toxicology 1996; 34:887-
904.
15- Sulieman MA. An overview of tooth-bleaching techniques: chemistry, safety and efficacy. Periodontol 2000.
2008; 48:148-69.
37. 16- Greenwall L. The dangers of chlorine dioxide tooth bleaching. Aesthetic Dentistry Today 2008; 2:20-22.
17- Munro IC, Williams GA, Heymann HO, Kroes R. Tooth whitening products and the risk of oral cancer. Food
Chem Toxicol 2006; 44: 301-315.
18- Munro IC, Williams GA, Heymann HO, Kroes R. Use of hydrogen peroxide-based tooth whitening products
and the relationship to oral cancer. J Esthet and Rest Dent 2006; 18:119-125.
19- 12 Agency for Toxic Substances and Disease Registry. Medical Management Guidelines for Hydrogen
Peroxide (H2O2). September 2007. Retrieved August 26, 2009, from
http://www.atsdr.cdc.gov/MHMI/mmg174.html.
20- Scientific Committee on Consumer Products (European Commission). Opinion on hydrogen peroxide in
tooth whitening products. SCCP/0844/04, March 15, 2005.
21- Gerlach RW, Zhou X. Comparative clinical efficacy of two professional bleaching systems. Compend
Contin Educ Dent 2002; 23: 35-41.
22- Kugel G, Aboushala A, Zhou X, Gerlach RW. Daily use of whitening strips on tetracycline-stained teeth:
comparative results after 2 months. Compend Contin Educ Dent 2002; 23:29-34.
23- Ritter AV, Leonard RH, St. Georges AJ, Caplan DJ, Haywood VB. Safety and stability of nightguard vital
bleaching: 9-12 years post-treatment. J Esthet Restor Dent 2002; 14275-285.
24- Leonard RH Jr, Bentley C, Eable JC, Garland GE, Knight MC, Phillips C. Nightguard vital bleaching: a
long-term study on efficacy, shade retention, side effects, and patients’ perceptions. J Esthet Restor Dent
2001; 13:357-369
25- Hasson H, Ismail AI, Neiva G. Home-based chemically-induced whitening of teeth in adults. Cochrane
Database of Systematic Reviews 2006, Issue 4.
26- Cubbon T, Ore D. Hard tissue and home tooth whiteners. CDS Review 1991;June:32-35.
27- Hammel S. Do-it-yourself tooth whitening is risky. US News and World Report 1998; April 2:66.
28- Al-Salehi SK. Effects of bleaching on mercury ion release from dental amalgam. J Dent Res 2009; 88:239-
43.
29- American Dental Association. Guidelines for the acceptance of peroxide-containing oral hygiene
products. J Am Dent Assoc 1994; 125:1140-1142.
38. 30- Scientific Committee on Consumer Products (European Commission).
Opinion on hydrogen peroxide, in its free form or when released, in oral
hygiene products and tooth whitening products. SCCP/1129/07, December 18,
2007.
31- Lee SS, Zhang W, Lee DH, Li Y. Tooth whitening in children and
adolescents: a literature review. Pediatric Dentistry 2005;27:362-368.