An Overview of Vital Tooth Bleaching

Abstract

Bleaching of tooth discolorations became more attractive with the increasing importance of aesthetics. Therefore, in recent years, bleaching treatment has become one of the fastest-growing parts of aesthetic dentistry. Bleaching can generally be carried out with hydrogen peroxide or carbamide peroxide both at-home and in-office. Bleaching systems have been offered to the public as a more conservative and economical approach for improving dental appearance. However, the dental profession should maintain high ethical standards and not recommend cosmetic adjustments to the tooth color to suit the patient's demand. Therefore, in this article, vital tooth whitening applications are discussed.

Full text

115
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Volume 2 No 2 | May 2020, 115-139
Review
An Overview of Vital Tooth Bleaching
Soner Şşmanoğlu1 ORCID: 0000-0002-1272-5581
1Department of Restoratve Dentstry, School of Dentstry, Altınbaş Unversty, Istanbul, Turkey
Submtted: January 21, 2020; Accepted: Aprl 24, 2020
Abstract: Bleaching of tooth discolorations became more attractive with the increasing importance of aesthetics.
Therefore, in recent years, bleaching treatment has become one of the fastest-growing parts of aesthetic dentistry.
Bleaching can generally be carried out with hydrogen peroxide or carbamide peroxide both at-home and in-oce.
Bleaching systems have been oered to the public as a more conservative and economical approach for improving
dental appearance. However, the dental profession should maintain high ethical standards and not recommend
cosmetic adjustments to the tooth color to suit the patient’s demand. Therefore, in this article, vital tooth whitening
applications are discussed.
Keywords: Discoloration; tooth color; bleaching; whitening; vital
Address of Correspondng: Soner Şşmanoğlu-soner.s@hotmal.com Tel.: +90(212)7094528; Fax:
+90(212)5250075. Department of Restoratve Dentstry, Faculty of Dentstry, Altınbaş Unversty, Zuhuratbaba,
İncrl Caddes No: 11-A, 34147 Bakırköy, İstanbul, Turkey
1. Introducton
Cosmetic dentistry is a very important part of dental restorative applications. Nowadays, individuals are
not only content with healthy teeth but also want to have a perfect smile (Joiner, 2004). With the increase
in aesthetic concerns, individuals often apply to dental clinics for a whiter smile. The majority of these
individuals are not satised with the color of their teeth, and whiter teeth are thought to be related to
health and beauty and are preferred. In a study of patient satisfaction with their tooth color, researchers
reported indierence up to 50%, 30% were dissatised, and 10% were very dissatised with their tooth
color (Odioso et al., 2000). Composite resin and porcelain veneers, crowns, composite resin restorations,
mechanical abrasion, and bleaching are among the preferred treatments for tooth discoloration. In a
survey conducted by Clinical Research Associates, 91% of dentists reported that they used bleaching
treatment in their clinics with a success rate of 79% (Christensen and Christensen, 1995). Furthermore, it
has been reported that some of the adolescents aged between 14 and 19 have bleached their teeth and

116
Vital Tooth Bleaching
have the idea of having bleaching again (Boeira et al., 2016). Vital bleaching procedures for the treatment
of discoloration are a more conservative and cost-eective approach compared to restorative treatments
(Barghi, 1998; Dutra et al., 2004). Bleaching treatment can be carried out by the dentist in-oce or at-
home by the patient under the control of the dentist (Haywood, 1992; Haywood and Heymann, 1989;
Sulieman et al., 2005). High concentrations of hydrogen peroxide or carbamide peroxide are used to
provide fast, safe and very eective bleaching in-oce (Garber, 1997; Haywood, 1992; Lee et al., 1995;
Sulieman et al., 2003).
2. Dscoloraton
Tooth discolorations are categorized as extrinsic and intrinsic discolorations according to their origin (Nathoo,
1997; Watts and Addy, 2001; Zantner et al., 2006). Extrinsic discoloration is caused by the consumption
of chromogenic foods and beverages, tobacco products, medicaments such as chlorhexidine (Haywood
and Heymann, 1989; Watts and Addy, 2001). Acquired pellicle is a formation that is prone to discoloration
(Viscio et al., 2000), and extrinsic discolorations are often observed in areas adjacent to gingival margins
and interdental papillae, which are dicult to reach by insucient brushing (Freedman et al., 2012).
Therefore, while scaling and polishing treatments remove most of the extrinsic discolorations (Walsh,
2000; Yap and Wattanapayungkul, 2002), bleaching treatments are applied to remove stubborn stains
(Duckworth, 2006; Joiner et al., 2002).
Intrinsic discoloration is caused by the passage of chromogenic substances into the enamel and dentin
tissue during odontogenesis or during tooth eruption (Swift and Perdigão, 1998; Watts and Addy, 2001).
Dental uorosis due to the high levels of uoride exposure, the use of tetracycline antibiotics, hereditary
diseases and traumas aecting tooth development are among the main causes. After the eruption, pulp
necrosis, discoloration due to some restorative materials and iatrogenesis are also considered in this
category. Thereby, intrinsic discolorations can occur for many dierent reasons and are also divided into
two according to the formation period: pre-eruptive and post-eruptive intrinsic discolorations.
2.1. Pre-Eruptve Intrnsc Dscoloraton
Dental Fluorosis
Dental uorosis is characterized by a high concentration of uoride exposure to enamel during tooth
development, resulting in decreased mineral content and consequently increased porosity on the enamel
surface. Dental uorosis can be in forms ranging from a white cloudy manifestation to a discolored
perforation. The severity of dental uorosis varies depending on the period of exposure and intensity of
the uoride. Today, Thylstrup and Fejerskov (TF) index is used in the classication and treatment planning
of dental uorosis (Sherwood, 2010; Thylstrup and Fejerskov, 1978). The extent of the dental uorosis is
classied from 1 to 6 according to the TF index. Patients with a TF score of 3 or less may be treated with
bleaching to mask the localized, chalky appearance of uorosis with no cavitation. Thus, the surrounding
healthy enamel is bleached and localized uorosis is rendered relatively vague. However, in cases where
enamel loss is evident, TF score 4 and above, resin inltration or other restorative treatment options
should be considered (Akpata, 2001).

117
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Antibiotics
The most common antibiotic-related tooth discoloration is due to tetracycline. Tetracycline interacts with
the calcium at hydroxyapatite crystals and forms a tetracycline-calcium phosphate complex. The oxidation
of tetracycline molecules in the tetracycline-calcium phosphate complex results in tetracycline-induced
tooth discoloration (Azer et al., 2011). Clinically, teeth with tetracycline discoloration may present light
yellow to dark gray colored bands (Haywood, 1991). These bands indicate the period of tooth development
corresponding to tetracycline exposure. Bluish-grayish bands may be observed in the discoloration of
minocycline, a derivative of tetracycline. Minocycline discoloration can be misdiagnosed with pulpal
hemorrhages in severe discoloration cases (Sánchez et al., 2004).
Tetracycline can cross the placenta barrier and therefore aect both primary and permanent dentition.
Discoloration in permanent teeth is less intense but more common compared to primary teeth. Tetracycline
exposure, even as short as 3 days, may cause tooth discoloration from intrauterine 4th month to 9 years
old (Sánchez et al., 2004). Yellowish-brown discolorations can be treated more successfully than gray-
bluish discolorations in terms of bleaching treatment (Freedman et al., 2012; Haywood, 1991; Haywood,
2000). In addition, selective etching of brown discoloration bands before the bleaching may increase the
eectiveness (Freedman et al., 2012).
Some researchers have reported amoxycillin-clavulanic acid-related tooth discoloration and stated that
this coloration is dose dependent (Garcia-Lopez et al., 2001).
2.2. Post-Eruptve Intrnsc Dscoloraton
Post-traumatic pulpal hemorrhage is the most common cause of post-eruptive intrinsic discoloration.
Blood enters the dentin tubules and decomposes so that the degradation products cause discoloration.
Pulp extirpation or necrosis can also lead to the formation of chromogenic degradation products (Arens,
1989). In addition, the physiological abrasion of the enamel together with the increase in secondary dentin
and dentin sclerosis due to aging, aect the light transmittance of the tooth, thereby the tooth appears
more yellow (Watts and Addy, 2001).
3. Hstory of The Tooth Bleachng
Whiter teeth have been people’s quest for ages. The rst record for tooth bleaching is based on
Assyro-Babylonian (Akkadian) cuneiform tablets (Aschheim, 2014). Since the beginning of the 19th
century, dentists have begun to perform cosmetic procedures such as bleaching and tooth contouring.
However, during these periods, bleaching was controversial among dentists due to its technical
sensitivity and the poor prognosis of the whitening eect. In the second half of the 19th century
oxalic acid was used to whiten vital teeth (Haywood, 1992). From the beginning of the 20th century,
oxalic acid was replaced by pyrozone (ether peroxide) (Atkinson, 1892) and hydrogen peroxide as
an oxidizing agent. Initially, hydrogen peroxide was administered to patients in liquid form (Fisher,
1911). In 1990, hydrogen peroxide was made available to dentists in gel form (Bartlett, 2001) and it

118
Vital Tooth Bleaching
was applied in a much safer way. Nowadays, hydrogen peroxide used for in-oce bleaching approach
is presents in gel and powder-liquid forms with concentrations ranging from 25% to 40% (Haywood,
2000; Ontiveros, 2011).
4. Mechansm of Bleachng
In recent years, hydrogen peroxide and carbamide peroxide have been used as bleaching agents.
Carbamide peroxide can be used in dierent concentrations. Bleaching with carbamide peroxide
is dierent from hydrogen peroxide bleaching. First, the carbamide peroxide disintegrates into
hydrogen peroxide and urea (Joiner, 2004). Carbamide peroxide with the concentration of 10%
disintegrates into 6.6% urea and 3.4% hydrogen peroxide. Then, urea is broken down into carbon
dioxide and ammonia.
Hydrogen peroxide can be used in dierent concentrations. Although it is known that hydrogen peroxide
is easily diused through enamel due to its lower molecular weight, it is not known exactly how it whitens
teeth (Bowles and Ugwuneri, 1987). According to the chemical theory explaining the bleaching reaction
of hydrogen peroxide, active hydrogen peroxide disintegrates into water (H
2
O) and oxygen (O
2
) and
perhydroxyl radicals (HO2). Bleaching is also known as an oxidation-reduction reaction. Peroxides are
converted to unstable free radicals (Hannig et al., 2003; Kashima-Tanaka et al., 2003). The free radicals
formed as a result of the decomposition of hydrogen peroxide, diuse into the interprismatic regions of
the enamel and carry the small molecules that it detaches from large organic molecules to the surface
due to its foaming properties. These free radicals react with organic molecules causing discoloration and
result in simple molecules that reect less light (Sulieman, 2004).
Another theory for the mechanism of the peroxide reaction is carbon-carbon bond cleavage causing
the ring-opening of the chromophores. Yellow double-bonded carbon compounds are converted to
almost colorless hydroxyl compounds (Haywood, 2001). Studies have shown that hydrogen peroxide
modies these long-chained chromophores to more translucent molecules and provides bleaching in
tooth discoloration. Chromophores are divided into two: long-chain organic compounds with double
bonds and metal-containing compounds. Bleaching of organic compounds with hydrogen peroxide
involves oxidation of double bonds. This causes the simpler molecules to reect less light, making the
darker regions lighter. Bleaching of the metallic compounds is more dicult, hence invasive restorative
treatments may be a better treatment option for such teeth (Carey, 2014).
As the bleaching process continues, a point is reached where only hydrophilic colorless structures remain.
This point is called the saturation point and bleaching slows down at this point. If the bleaching is further
continued, the carbon-containing dental tissues and the carbon bonds of the proteins are destroyed.
At this stage, excessive bleaching disrupts tooth enamel without whitening and results in irreversible
alterations on the enamel structure and mineral loss (Vilhena et al., 2019).

119
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
5. Composton of Bleachng Agents
The current bleaching materials contain hydrogen peroxide or carbamide peroxide as the active ingredient
(Joiner, 2004; Joiner and Thakker, 2004). Along with the active ingredient, inactive ingredients, such as
thickening agents, carriers, surfactants and pigment dispersants, preservatives, and avorings are also
present in bleaching materials (Gokay, 2005; Greenwall, 2001; Hannig et al., 2003; Joiner and Thakker,
2004; Kashima-Tanaka et al., 2003).
Thckenng Agents
The most commonly used thickening agent in bleaching gels is carbopol (carboxypolymethylene), which
is a high molecular weight polyacrylic acid polymer (Joshi, 2016). Thickening agents increase the viscosity
of the bleaching material and increase its retention to the applied surface. On the other hand, it slows
the release of active oxygen in hydrogen peroxide up to four times (Rodrigues et al., 2007), reducing the
need for replacement of the bleaching material during the process (Gokay et al., 2005; Greenwall, 2001;
Joiner and Thakker, 2004).
Carrers
Glycerin and propylene glycol are generally used in bleaching gels (Joshi, 2016). Glycerin increases the
viscosity of the bleaching material and provides ease of use, but causes dehydration (Greenwall, 2001).
Dehydration results in a temporary loss of tooth translucency. Propylene glycol does not cause dehydration
and retains moisture. It also contributes to the dissolution of other ingredients in the bleaching material
(Joiner and Thakker, 2004).
Surfactants and Pgment Dspersants
Surfactants as surface wetting agents provide a much better spread of bleaching material to the tooth
surface (Feinman et al., 1991). Therefore, surfactant agents increase the eectiveness of the bleaching
material (Gerlach et al., 2002). Pigment dispersants also keep pigments to remain in the bleaching gel
(Alqahtani, 2014).
Preservatves
Various preservatives are used in the composition of bleaching materials. Sodium benzoate and methyl
propyl paraben are added to prevent bacterial growth in the bleaching gel (Joiner and Thakker, 2004).
On the other hand, preservatives such as citric acid, citroxain, phosphoric acids or sodium stannate also
prevent the breakdown of hydrogen peroxide, until its use. These preservatives increase the stability and
durability of the bleaching gel while keeping the pH of the gel mildly acidic (Joshi, 2016).
Flavorngs
Flavorings such as banana, melon, peppermint are added to increase patient acceptance of the bleaching
material (Alqahtani, 2014; Joiner and Thakker, 2004).

120
Vital Tooth Bleaching
Addtves
Various substances are added to the bleaching materials to eliminate the side eects of the bleaching
treatment (Sulieman, 2008).
Amorphous Calcum Phosphate-Casen Phosphopeptde
Amorphous calcium phosphate-casein phosphopeptide (ACP-CPP) provides rapid desensitization by
causing depletion of phosphate and calcium ions to exposed dentin tubules (Giniger et al., 2005). It has
been reported that the incorporation of ACP-CPP into the bleaching gel signicantly reduces sensitivity
and increases bleaching eciency (Joshi, 2016).
Fluorde
It is known that uoride blocks the dentin tubules and relieves sensitivity by decelerating the dentinal uid
ow (Petersson, 2013). Fluoride also enhances the microhardness of enamel (Attin et al., 2007; Basting et
al., 2003) and hence uoride-containing bleaching gels have been reported to cause less demineralization
without aecting the bleaching eciency (Chen et al., 2008). Furthermore, in 2013, the present author
reported that uoride pretreatment before 35% hydrogen peroxide bleaching resulted in lower surface
roughness compared to no uoride-treated controls (Sismanoglu et al., 2013). It has also been reported
that the uoride incorporated into the bleaching gel positively contributes to the consequent restorative
treatments regarding the bond strength (Chuang et al., 2009).
Potassum Ntrate
Potassium nitrate shows an anesthetic-like eect by preventing the repolarization of the depolarized
nerve (Poulsen et al., 2006; Tarbet et al., 1981). This reduces post-operative sensitivity without altering
the bleaching eect. Matis et al., (2007) stated that ACP-CPP-containing bleaching gel provides similar
sensitivity reduction with potassium nitrate-containing bleaching gel, but showed less bleaching eect.
It has been reported to be eective even in light-activated bleaching (Browning et al., 2008; Haywood
et al., 2001; Tam, 2001).
6. Patent Selecton
Almost every patient may desire whiter teeth, but in each case, the aesthetic expectations of the patient
may not be adequately met or there is no guarantee that successful results would be achieved (Joshi,
2016). The indications for bleaching at-home and in-oce are basically the same, but the clinician should
decide the appropriate approach by the patient’s needs (Sulieman, 2008). The patient’s expectations,
lifestyle, the amount of time can be allocated for bleaching treatment, dental sensitivity, baseline shade,
and etiology of the discoloration are important factors in choosing the appropriate bleaching approach
for the patient (Sulieman, 2005). In the presence of caries, periapical lesion or hypersensitivity, priority
should be given to remedy these problems rather than bleaching (Sulieman, 2004). Furthermore, bleaching

121
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
is contraindicated in pregnancy, since the eects of bleaching materials on the fetus are still unknown
(Sulieman, 2005). The indications and contraindications of vital tooth bleaching are presented in Table 1.
Clinical trials, case reports, systematic reviews, and clinical experience provide the clinician with information
on which discoloration would respond to bleaching treatment (Joiner and Thakker, 2004; Sulieman, 2004,
2005). Yellow-toned teeth, which generally do not have developmental pathology, can be eectively
bleached, whereas brown stains may be more stubborn. For instance, brown stains caused by tobacco
consumption generally respond to longer bleaching regimes (Kugel et al., 2002). In addition, there is also
a relationship between sclera and shade of teeth. If the teeth to be bleached are lighter than the sclera,
bleaching success would be less (Greenwall, 2001). It has not been established that gender aects the
bleaching outcome (Gerlach and Zhou, 2001), but eective bleaching is achieved for younger individuals
compared to older ones (Joshi, 2016). Although white uorosis spots are not suitable for bleaching, they
become less pronounced as a result of bleaching the surrounding enamel (Haywood, 2000; Sulieman, 2004).
More interventional restorative or resin inltration treatments should be considered for individuals with
moderate to severe uorosis. Moreover, bleaching of extensive tetracycline discoloration is quite dicult
and may require the application of months-long bleaching regimens (Haywood, 2000; Sulieman, 2004).
Therefore, direct or indirect restorative treatments are preferred to cover tetracycline discoloration bands.
7. Types of Vtal Teeth Bleachng
Treatment of discolorations begins with the removal of extrinsic stains by polishing until then the bleaching
can be performed. There are basically three dierent bleaching approaches: in-oce or power bleaching
(Feinman et al., 1987), at-home or dentist-supervised nightguard vital tooth bleaching (Haywood and
Heymann, 1989), and bleaching with the over-the-counter (OTC) products (Kihn, 2007; Sagel et al., 2000).
Bleaching systems and materials can be classied according to the active ingredient, and the application/
delivery method. The American Academy of Cosmetic Dentistry classies bleaching systems according
to their application/delivery methods (Joshi, 2016).
Whtenng Toothpaste
These toothpastes contain higher amounts of abrasive particles and detergents than whitening agents
compared to the standard toothpastes and remove extrinsic stains on the tooth surface (Lima et al., 2008).
The enzymes contained in their chemical formulae cause the decomposition of organic molecules in the
pellicle. It should not be ignored that abrasive particles can cause a permanent loss of enamel on tooth
surfaces (Joiner et al., 2008). Some toothpastes may contain relatively low concentrations of carbamide
peroxide or hydrogen peroxide as a whitening agents instead of abrasive particles. The whitening agent
must be kept separate from dentifrice until its use to keep the agent stable. Dual-chambered tube
technology enables this separation. It is stated that tooth color can be bleached one to two shades
with whitening toothpastes. In addition, a silica toothpaste containing blue covarine has attracted great
attention in recent years. With this toothpaste, which is a good example of the adaptation of metamerism
to dentistry, teeth are perceived as whiter.

122
Vital Tooth Bleaching
Whtenng Mouthwashes
The whitening mouthwashes contain a low concentration of hydrogen peroxide (2%) and sodium
hexametaphosphate to prevent tooth discoloration. Prolonged use may irritate the oral mucosa and
tooth sensitivity (Carey, 2014).
Whtenng Strps
Recently, whitening strips are developed to make the bleaching gel easier to apply as an alternative to
other bleaching systems (Alqahtani, 2014; Sagel et al., 2000). These bleaching strips contain 150-200
mg of bleaching gel homogeneously distributed on the surface of exible polyethylene material. The
concentration of hydrogen peroxide ranges from 5.3% to 6.5% (Donly et al., 2007), and patients are
advised to use this system for 30 minutes twice a day for 14 days long. Bleaching strips are very popular
because they are easy to apply, cost-eective and have a considerable bleaching eect (Alqahtani, 2014;
Gerlach and Barker, 2004).
Pant-on Systems
These products are based on the application of a suspension containing hydrogen peroxide or carbamide
peroxide to the tooth surface with a brush (Kishta-Derani et al., 2007). However, their bleaching activity is
considerably low. This is most likely due to the short contact time of the bleaching agent (Lo et al., 2007).
Tray-Based Tooth Whteners
These whitening products are oered directly to the consumer without any control of the dentist, such as
other cosmetic products. OCT products appeared in the United States in the early 2000s. These products
whiten teeth at lower costs than professional treatments (Demarco et al., 2009). However, these products
are generally dispersed by standard/uniform trays and can cause gingival irritation because they are
applied without custom tting trays (Demarco et al., 2009).
At-Home Bleachng (Nghtguard Vtal Tooth Bleachng)
Although the bleaching eect of carbamide peroxide was discovered randomly in the late 1960s by B.
Klusemeir, an orthodontist (Joshi, 2016), the nightguard vital tooth bleaching approach at home was
rst described in 1989 by Haywood and Heymann (1989). Although this method has undergone many
changes to date, it is essential that bleaching agents containing carbamide peroxide are used for 2 to 6
weeks in custom tting trays for a period of 6 to 8 hours a day.
Usually, 10-15% carbamide peroxide is recommended for this bleaching technique. The bleaching materials
are in the form of a transparent gel or white pat. Carbopol-containing bleaching materials are preferred
because carbopol increases viscosity and prolongs the oxidation process (Gokay et al., 2005; Greenwall,
2001; Joiner and Thakker, 2004; Rodrigues et al., 2007). The 10% carbamide peroxide agent is composed

123
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
of 3.5% hydrogen peroxide and 6.5% urea. The presence of urea gives the agent a longer shelf life and
slows the release of hydrogen peroxide. Many studies have shown that it is safe and eective to perform
bleaching agents containing carbamide peroxide in accordance with dentist recommendations (Haywood
and Heymann, 1991). However, patients’ cooperation on long-term tray usage is poor.
In-Offce Bleachng
For in-oce bleaching, hydrogen peroxide is generally used in concentrations ranging from 25% to
40%. The bleaching process is completely under the control of the dentist and can be stopped when the
desired shade is reached. Hydrogen peroxide is a material with caustic eects and therefore protective
measures such as rubber-dam or gingival barrier should be taken during its application (Sulieman, 2008).
Penetration of hydrogen peroxide to the pulp chamber is also possible, but considering its long-term
eect, it does not cause any adverse eects on the pulp (McEvoy, 1995).
The in-oce bleaching approach can be used in patients who do not have enough time for the at-
home bleaching approach, who have gag reexes or who do not like the taste of home bleaching gels.
Another advantage is that the immediate results obtained for the in-oce bleaching motivate the patient
to continue with bleaching at-home to maximize the outcome. Therefore, the in-oce bleaching was
frequently combined with at-home bleaching.
The bleaching process can be activated with the help of heat and light to increase the speed and
eectiveness of the bleaching treatment. Hence, in-oce bleaching approach is also called as “power
bleaching”. Nowadays, heat application has been abandoned due to possible harmful eects on pulp.
Manufacturers produce many light devices specic to tooth bleaching. With the help of these devices, the
disintegration ratio of hydrogen peroxide increases and the decomposition of chromophore molecules
through oxidation is accelerated, thereby the time required for bleaching is decreased. One of the uses
of lasers in dentistry is tooth bleaching. The most commonly used lasers in this eld are diode, CO2 and
argon lasers. Using photons of a specic wavelength close to the absorption spectrum of the bleaching
agent (480 nm and 520 nm) would increase the chemical reaction rate and reduce the bleaching time
(Downs et al., 2011). Torres et al. (2009) reported that the laser activates highly reactive hydrogen peroxide
molecules, enabling them to rapidly ionize.
The most used power bleaching sets include hydrogen peroxide gel, light-cured gingival barrier material,
neutralizing gel and/or neutral uoride gel. Although the use of rubber-dam is recommended for the
isolation of soft tissues, gingival barriers are frequently used in the power bleaching process as the rubber-
dam may cause application problems at the gingival third of the teeth. Following the application of the
gingival barrier, the hydrogen peroxide gel is applied to the surfaces to be bleached according to the
manufacturer’s instructions forming approximately 3-mm thick layer (Figure 1). Although the process varies
from brand to brand, it is usually repeated 3 times in about 10-15 minutes. Each repetition is termed as
“passes” (Joshi, 2016). After each passes, the whitening gel is cleaned over the teeth with suctioning and
wiping using clean gauze. If the bleaching gel leaks despite the gingival barrier and comes into contact
with soft tissues during bleaching, it may cause blanching and irritation. If this happens, the irritated area

124
Vital Tooth Bleaching
should be washed with plenty of water and the neutralizing agent supplied with the bleaching kit should
be applied. Generally, these neutralizing agents include vitamin E, which is an antioxidant. The bleaching
process can be resumed after the reapplication of the gingival barrier.
All bleaching agents that are not at neutral pH reduce the microhardness and modulus of elasticity and
increase the surface roughness of the enamel. This increase in roughness creates a favorable environment
for extrinsic discoloration (Azer et al., 2009; Pinto et al., 2004). Therefore, bleached enamel surfaces should
be polished. Subsequent to bleaching, a neutral uoride gel can be applied to teeth. It is noteworthy,
the teeth appear lighter than it is due to the postbleaching dehydration, and slight rebound occurs on
rehydration. This should be considered by the clinician, and color evaluation should be better after 1-2
days (Haywood, 1996).
Combnaton Treatments
The combined use of both in-oce bleaching and at-home bleaching approaches is often preferred by
dentists. Especially in the treatment of tetracycline discolorations or cases of discoloration with dierent
etiology, such an application provides successful results. Patient cooperation is another important factor
in the success of bleaching treatment (Odioso et al., 2000). In particular, for the patients with weak
motivation, initiating the bleaching treatment with in-oce bleaching before at-home bleaching would
increase the motivation towards treatment and aect their cooperation positively.
Another combination is the use of whitening toothpaste after bleaching treatments. Such a combination
would be useful to prevent as much of the rebounds as possible after bleaching to maintain color stability.
8. Adverse Effects of The Bleachng
The most common side eects of tooth bleaching are recurrence of the discoloration, hypersensitivity,
irritation of gingival tissue and oral tissues, alterations on enamel and restorative material surfaces (Li
and Greenwall, 2013). Apart from these, tray-based tooth whiteners without dentist orientation may also
cause temporomandibular joint problems (Gerlach et al., 2009).
8.1. Recurrence of The Dscoloraton
To assess and understand the reversal of the whitening eect, patients’ tooth shade should be recorded
before the bleaching process. According to all clinical and laboratory research results, tooth bleaching is
eective and safe with the latest generation of vital whitening products (Li, 2003; Luk et al., 2004). Reversal
after in-oce bleaching has been reported at a rate of 41% per year according to Clinical Research Associates
(2004). For at-home bleaching, a return of 26% in 18 months and stated that the original concentration
of bleaching agent is not relevant to the reversal rate (Meireles et al., 2009).
After the completion of in-oce bleaching or after the removal of the tray at at-home bleaching,
patients often notice a large bleaching eect due to the eect of dehydration. It is better to perform
the nal color evaluation 1-2 days after bleaching (Haywood, 1996). To prevent reversal, it may be

125
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
advisable to use whitening toothpastes, and it may be recommended for patients to undergo annual
at-home bleaching.
All bleaching agents result in a reduction in enamel microhardness and modulus of elasticity after
bleaching and result in surface roughness. This increase in roughness creates an environment conducive
to extrinsic coloration (Azer et al., 2009; Pinto et al., 2004). Therefore, after whitening, tooth surfaces
should be polished.
8.2. Hypersenstvty
Hypersensitivity is the most commonly reported adverse eect of bleaching. The frequency of
hypersensitivity observed in patients using 10% carbamide peroxide is ranging between 11 to 93%
(Leonard et al., 2002) and the average initial reporting time of hypersensitivity is after 5 days (Tam,
1999). This side eect is usually mild and temporary pain; often causes signicant discomfort in
the patient (Rosenstiel et al., 1996). The cause of sensitivity after bleaching is explained by dierent
mechanisms such as hydrodynamic theory or morphological changes in enamel (increased surface
porosity, precipitation, supercial irregularities). However, recent studies have indicated that direct
activation of neuronal receptors may be the main reason for the occurrence of this sensitivity. It has
been reported that with the addition of agents, which inhibit the activation of neuronal receptors such
as potassium nitrate to the bleaching materials, it is possible to reduce the severity of this sensitivity
without resulting in a decrease in bleaching eciency (Markowitz, 2010). Potassium nitrate, sodium
uoride or ACP-CPP can be incorporated into bleaching materials as desensitizing agents or applied
to the tooth surface prior to bleaching (Tay et al., 2009).
8.3. Alteraton on The Enamel Surface
Micro- and nano-mechanical investigations have shown that bleaching agents reduce enamel hardness,
modulus of elasticity and fracture resistance. This decrease occurs regardless of peroxide concentration,
pH or exposure time (De Abreu et al., 2011). Therefore, the decrease in stiness and modulus of elasticity
is thought to be due to the protein denaturation (Ushigome et al., 2009). In a study, it was stated that
carbamide peroxide causes more protein denaturation compared to hydrogen peroxide and urea content
in carbamide peroxide may cause this situation (Elfallah et al., 2015). Besides, it is reported that the mineral
loss as a result of bleaching does not cause harm to the tooth (Goo et al., 2004). Furthermore, mineral
loss due to 12-hour bleaching treatment is similar to mineral loss caused by a few minutes of soft drink
or juice exposure (Lee et al., 2006). When these studies are taken into consideration, alterations caused
by bleaching in the enamel can be considered insignicant (Alqahtani, 2014).
Each tooth has its nal level of lightness, which is called “inherent lightness potential” (Matis et al., 2000).
This point represents the endpoint of the bleaching process for that tooth. If bleaching is continued
after this point, no more whiteness can be achieved, besides irreversible damage to the enamel may
occur. Studies have reported that this endpoint can be reached regardless of the active ingredient and
concentration used for bleaching over 6 weeks.

126
Vital Tooth Bleaching
In some studies, whitening products have been reported to increase surface alterations in enamel. When
compared with untreated control groups, the bleached enamel surface undergoes morphological changes
(Alqahtani, 2014). However, these changes have been reported to be reversible (Demarco et al., 2011). After
bleaching, dentists advise their patients, especially against smoking and some chromogenic beverages
(Cavalli et al., 2004; McGuckin et al., 1992; Titley et al., 1988). Coee, tea, fruit juices, red wine, and sodas
are chromogen beverages that have the potential to stain or discolor the bleached enamel surface. The
bleached enamel surface may be very sensitive to discoloration, especially in acidic solutions (Berger
et al., 2008). Mouth rinsing or brushing can be performed immediately after the consumption of foods
and beverages to prevent discoloration. Patients can use straws while consuming beverages. In patients
who smoke and drink beverages that cause the excessive coloration, it may be necessary to repeat the
whitening process very often.
8.4. Effects on Pulp Tssue
The risk of dentin pulp complex being aected by dental materials depends on the permeability of the
components of these products through enamel and dentin (Hanks et al., 1993). The diusion of H2O2
has been shown to increase with increasing concentration and duration of administration (Matis et al.,
2000). H2O2-induced free radicals cause oxidative stress in pulp cells. As a result, further tissue damage is
prevented by releasing endogenous antioxidant agents such as peroxidase and catalase from pulp cells
(de Souza Costa et al., 2010). Although the cytotoxic eect of H2O2 on the pulp is proven, pulpal cells are
sucient to eliminate this eect and initiate odontoblastic dierentiation (Soares et al., 2015; de Souza
Costa et al., 2010).
8.5. Soft Tssue Effects
The contact of bleaching agents with oral tissues causes chemical burns. If this contact is short-term, it is
seen as whitening of the tissue and this whiteness disappears within a few hours. Ulceration may occur
for longer periods of contact. In such cases, topical vitamin E administration should be recommended
to accelerate healing (Li and Greenwall, 2013).
8.6. Effects on Restoratve Materals
In most of the studies in the literature, composite resins have been investigated as restorative materials. In
a laboratory study, a 3-week application of 10% carbamide peroxide has been shown to alter the surface
roughness of composite resins (Basting et al., 2005). However, surface microhardness was not signicantly
changed (Basting et al. 2005). In situ studies also showed no change in surface microhardness as a result
of the application of 15% carbamide peroxide to composite resins for 4 weeks (Li et al., 2009; Yu et al.,
2008). In fact, the bleaching of these composite resins have also been observed (Li et al., 2009). The authors
commented that this bleaching may be related to surface changes and oxidation of chromophores. On
the other hand, in another laboratory study, the eect of a 2-week administration of 10% carbamide
peroxide on the surface microhardness was examined under two dierent storage temperatures (Yu et

127
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
al., 2011). No signicant dierence was observed in the surface microhardness for specimens stored at
room temperature (25°C), while a signicant softening was observed for the specimens stored at body
temperature (37°C) (Yu et al., 2011).
There are several controversies among studies on subsurface microhardness. Yu et al., (2011) reported that
the subsurface microhardness of bleaching-induced composite resins was stable at dierent environment
temperatures. However, Hannig et al., reported that composite resin subsurface microhardness may be
aected up to 2-mm after bleaching (Hannig et al., 2007). Therefore, it is certain that further studies are
needed on this subject.
In many studies, it has been reported that application of carbamide peroxide does not cause adverse
eects on exural strength and fracture toughness of composite resins (Cho et al., 2009; Hatanaka et al.,
2013; Yu et al., 2010). In addition, in-oce bleaching with higher concentrations did not alter the tensile
bond strength of composite resins (Cullen et al., 1993; Yap and Wattanapayungkul, 2002). As a result,
if bleaching treatment is applied in the presence of composite resin restorations, polishing of these
restorations after the treatment would be appropriate.
Bleaching treatment is known to cause the release of monomer and some other substances on dental
composites. Durner et al., (2011) reported that bleaching with hydrogen peroxide degrades three-
dimensional polymer networks in composites when compared to non-bleaching controls, leading to an
increase in the release of unpolymerized monomers and other substances.
According to the information obtained from laboratory studies, it has been shown that mercury release
is increased in dental amalgams in contact with carbamide peroxide. Bleaching agents have been shown
to improve the solubility of glass-ionomer and other cements (El-Murr et al., 2011; Yu et al., 2009; Yu et
al., 2015). Polyacid modied resin-based composites, resin-modied glass-ionomer cements, and zinc-
oxide cements are exhibited increased softening and uoride release in contact with high-concentration
bleaching agents. Moreover, cracks have also been reported in some studies (Yu et al., 2015).
The decrease in the bond strength of adhesive restorations after the application of hydrogen peroxide
has been proven by many researchers. The reason for this decrease is the changes in enamel structure,
inhibiting the inltration of the resin by the breakdown of hydrogen peroxide and inhibiting the resin
polymerization (Cvitko et al., 1991; García-Godoy et al., 1993; Toko and Hisamitsu, 1993). It has been
reported that the resin tags in the bleached enamel are much shorter and fewer compared to the
unbleached controls (Titley et al., 1991). Therefore, it was stated that bond strength reduction reversed
if the procedure is delayed for 2 weeks (Da Silva Machado et al., 2007). Unlu et al., (2008) recommended
delayed bonding for at least 24 hours after bleaching with 10% carbamide peroxide and for at least 1
week with 35% hydrogen peroxide bleaching. However, many studies indicate that a 1-week delay is not
sucient to obtain optimal bonding results (Bulut et al., 2006; Türkün and Kaya, 2004; Türkün et al., 2009).
In addition, studies have reported that the use of a number of antioxidant agents (green tea extract,
sodium ascorbate) as a pretreatment to reverse decreased bond strength. However, according to current
knowledge, delayed bonding for 2 weeks seems to be a more appropriate option.

128
Vital Tooth Bleaching
Bleaching-induced composite resins were found to be more susceptible to extrinsic discoloration due to
the surface softening (Yu et al., 2009). Furthermore, it has been reported that 10% carbamide peroxide
can remove extrinsic stainings such as juice, tea, and chlorhexidine on the composite resin surface (Fay
et al., 1999).
Table 1. Indcatons and contrandcatons of vtal tooth bleachng (Suleman, 2008)
Indications Contraindications
Generalized staining
Age-related discoloration
Smoking and dietary discoloration
Fluorosis
Tetracycline staining
Trauma-related discoloration
Higher patient expectation
Caries and periapical lesion
Pregnancy
Cracks and exposed dentine, sensitivity
Existing crowns or large restorations
Elderly patients with visible recession
Fgure 1. The bleachng gel appled to vestbular toot surfaces approxmately 3-mm n thckness
9. Consderatons
Patients are often eager for other aesthetic dental or orthodontic procedures after tooth bleaching.
However, as mentioned earlier, the bond strength of adhesive restorations or brackets is low in bleached
teeth (García-Godoy et al.,1993; Toko and Hisamitsu, 1993). Although dierent methods have been
tried to prevent this decrease in bond strength; the most commonly used method is delay bonding

129
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
of adhesive treatments after bleaching (Da Silva Machado et al., 2007). Lai et al., (2002) showed that
the decrease in bond strength of composite resins after tooth bleaching can be reversed by the use
of antioxidants. Ascorbic acid and its salts are products of low toxicity and used as antioxidants in the
food industry. Ascorbic acid has a mean pH of 4, while sodium ascorbate has a pH of 7. Therefore,
sodium ascorbate is a more suitable product for dental applications (Hansen et al., 2014; Vohra and
Kasah, 2014). In addition, it has been shown that 5 minutes of application is sucient for its antioxidant
eect (Freire et al., 2009). However, the delayed bonding option is still the best choice if the patient
does not have time constraints.
Light activation in combination with the in-oce bleaching approach is a controversial topic in the
literature. In recent systematic review and meta-analysis studies, the eect of light activation with in-
oce bleaching on the eectiveness of bleaching and tooth sensitivity was evaluated (Bernardon et al.,
2010; Buchalla and Attin, 2007; He et al., 2012). In these studies, it was reported that light activation does
not contribute to bleaching eciency. Contrarily, increased tooth sensitivity and potential pulp irritation
with the combination of light activation and use of high concentrations of hydrogen peroxide (25-35%)
was reported (He et al., 2012).
In-oce bleaching usually takes two or three sessions for eective and stable results. It is known that
clinicians prefer to leave a gap of 1 week between sessions. Although this is not evidence-based, it is a
common choice to reduce tooth sensitivity and prevent pulp damage. According to a recent study on
this subject, it was found that there was no signicant dierence between 2-days and 7-days of waiting
periods in terms of tooth sensitivity and bleaching eciency (De Paula et al., 2015). Thereby, it is a safe
way to wait at least 2 days between consecutive bleaching sessions.
Concluson
Tooth bleaching combines both aesthetic and conservative approaches for the removal of tooth
discoloration. Both the knowledge and experience of the clinician are critical for a thorough understanding
of the etiology of discoloration and the selection of the proper bleaching approach. Successful
treatment of these discolorations would increase patient satisfaction and motivation. However, the
dental profession should maintain high ethical standards and not recommend cosmetic adjustments
to suit the patient’s demand.
Acknowledgement
None.
Conflct of Interests
Author declares no conict of interests.

130
Vital Tooth Bleaching
References
de Abreu, D. R., Sasaki, R. T., Amaral, F. L. B., Flório, F. M., Basting, R. T. (2011). Eect of home-use and in-
oce bleaching agents containing hydrogen peroxide associated with amorphous calcium phosphate on
enamel microhardness and surface roughness. Journal of Esthetic and Restorative Dentistry, 23(3), 158–168.
Akpata, E. S. (2001). Occurrence and management of dental uorosis. International Dental Journal, 51(5),
325–333.
Alqahtani, M. Q. (2014). Tooth-bleaching procedures and their controversial eects: a literature review.
Saudi Dental Journal, 26(2), 33–46.
Arens, D. (1989). The role of bleaching in esthetics. Dental Clinics of North America, 33(2), 319–336.
Aschheim, K. W. (2014). Esthetic dentistry: a clinical approach to techniques and materials, 3rd Edition.
Elsevier Health Sciences.
Atkinson, C. B. (1892). Fancies and some facts. The Dental Cosmos, 34(12), 968-972.
Attin, T., Betke, H., Schippan, F., Wiegand, A. (2007). Potential of uoridated carbamide peroxide gels to
support post-bleaching enamel re-hardening. Journal of Dentistry, 35(9), 755–759.
Azer, S. S., Hague, A. L., Johnston, W. M. (2011). Eect of bleaching on tooth discolouration from food
colourant in vitro. Journal of Dentistry, 39(Suppl 3), 52–56.
Azer, S. S., Machado, C., Sanchez, E., Rashid, R. (2009). Eect of home bleaching systems on enamel
nanohardness and elastic modulus. Journal of Dentistry, 37(3), 185–190.
Barghi, N. (1998). Making a clinical decision for vital tooth bleaching: at-home or in-oce? Compendium
Of Continuing Education In Dentistry, 19(8), 831–838.
Bartlett, D. (2001). Bleaching discoloured teeth. Dental Update, 28(1), 14–18.
Basting, R. T., Rodrigues, A. L., Serra, M. C. (2003). The eects of seven carbamide peroxide bleaching agents
on enamel microhardness over time. Journal of the American Dental Association, 134(10), 1335–1342.
Basting, R. T, Fernandez, C. F., Ambrosano, C. M. B., Campos, I. T. (2005). Eects of a 10% carbamide peroxide
bleaching agent on roughness and microhardness of packable composite resins. Journal of Esthetic and
Restorative Dentistry, 17(4), 256–262.
Berger, S. B., Coelho, A. S., Oliveira, V. A., Cavalli, V., Giannini, M. (2008). Enamel susceptibility to red wine
staining after 35% hydrogen peroxide bleaching. Journal of Applied Oral Science, 16(3), 201–204.
Bernardon, J. K., Sartori, N., Ballarin, A., Perdigão, J., Lopes, G. C., Baratieri, L. N. (2010). Clinical performance
of vital bleaching techniques. Operative Dentistry, 35(1), 3–10.
BoeiraI, G. F., SalasI, M. M. S., AraújoI, D. C., MasottiI, A. S., CorreaI, M. B., Demarco, F. F. (2016). Factors
inuencing dental appearance satisfaction in adolescents: a cross-sectional study conducted in southern
brazil. Brazilian Journal of Oral Sciences, 15(1), 8–15.

131
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Bowles, W. H., Ugwuneri Z. (1987). Pulp chamber penetration by hydrogen peroxide following vital
bleaching procedures. Journal of Endodontics, 13(8), 375–377.
Browning, W. D., Chan, D. C., Myers, M. L., Brackett, W. W., Brackett, M. G., Pashley, D. H. (2008). Comparison
of traditional and low sensitivity whiteners. Operative Dentistry, 33(4), 379–385.
Buchalla, W., Attin, T. (2007). External bleaching therapy with activation by heat, light or laser-a systematic
review. Dental Materials, 23(5), 586–596.
Bulut, H., Turkun, M., Kaya, A. D. (2006). Eect of an antioxidizing agent on the shear bond strength
of brackets bonded to bleached human enamel. American Journal of Orthodontics and Dentofacial
Orthopedics, 129(2), 266–272.
Carey, C. M. (2014). Tooth whitening: what we now know. Journal of Evidence-Based Dental Practice,
14(suppl.), 70–76.
Cavalli, V., Giannini M., Carvalho, R. M. (2004). Eect of carbamide peroxide bleaching agents on tensile
strength of human enamel. Dental Materials, 20(8), 733–739.
Chen, H. P., Chang, C. H., Liu, J. K., Chuang, S. F., Yang, J. Y. (2008). Eect of uoride containing bleaching
agents on enamel surface properties. Journal of Dentistry, 36(9), 718–725.
Cho, S. D., Bulpakdi, P., Matis, B. A., Platt, J. A. (2009). Eect of bleaching on fracture toughness of resin
composites. Operative Dentistry, 34(6), 703–708.
Christensen, G. J. Christensen, R. P. (1995). Home use bleaching survey. CRA Newsletter 19(1).
Chuang, S. F, Chen, H. P., Chang, C. H., Liu, J. K. (2009). Eect of uoridated carbamide peroxide gels on
enamel microtensile bond strength. European Journal of Oral Sciences, 117(4), 435–441.
Cullen, D. R., Nelson, J. A, Sandrik, J. L. (1993). Peroxide bleaches: eect on tensile strength of composite
resins. The Journal of Prosthetic Dentistry, 69(3), 247–249.
Cvitko, E., Denehy, G. E., Swift, E. J., Pires, J. A. F. (1991). Bond strength of composite resin to enamel bleached
with carbamide peroxide. Journal of Esthetic and Restorative Dentistry, 3(3), 100–102.
Demarco, F. F., Meireles, S. S., Sarmento, H. R., Dantas, R. V., Botero, T., Tarquinio, S. B. (2011). Erosion and
abrasion on dental structures undergoing at-home bleaching. clinical. Cosmetic and Investigational
Dentistry, 3, 45–52.
Demarco, F. F., Meireles, S. S., Masotti, A. S. (2009). Over-the-counter whitening agents: a concise review.
Brazilian Oral Research, 23(Suppl. 1), 64–70.
Donly, K. J., Segura, A., Henson, T., Barker, M. L., Gerlach, R. W. (2007). Randomized controlled trial of
professional at-home tooth whitening in teenagers. General Dentistry, 55(7), 669–674.

132
Vital Tooth Bleaching
Downs, J., Convissar, R. A., Anagnostaki, E., Sun, G. (2011). Principles and practice of laser dentistry. In
Principles and Practice of Laser Dentistry, Missouri, 151.
Duckworth, R. M. (Ed.). (2006). The teeth and their environment: physical, chemical and biochemical
inuences. Karger.
Durner, J., Stojanovic, M., Urcan, E., Spahl, W., Haertel, U., Hickel, R., Reichl, F. X. (2011). Eect of hydrogen
peroxide on the three-dimensional polymer network in composites. Dental Materials, 27(6), 573–580.
Dutra, A., Frary, J., Wise, R. (2004). Higher-order needs drive new growth in mature consumer markets.
Journal of Business Strategy, 25(5), 26–34.
El-Murr, J., Ruel, D., St-Georges, A. J. (2011). Eects of external bleaching on restorative materials: a review.
Journal of the Canadian Dental Association, 77, 59.
Elfallah, H. M., Bertassoni, L. E., Charadram, N., Rathsam, C., Swain, M. V. (2015). Eect of tooth bleaching
agents on protein content and mechanical properties of dental enamel. Acta Biomaterialia, 20, 120–128.
Fay, R. M., Servos, T., Powers, J. M. (1999). Color of restorative materials after staining and bleaching.
Operative Dentistry, 24(5), 292–296.
Feinman, R. A., Madray, G., Yarborough, D. (1991). Chemical, optical, and physiologic mechanisms of
bleaching products: a review. Practical Periodontics and Aesthetic Dentistry, 3(2), 32–36.
Feinman, R. A., Goldstein, R. E., Garber, D. A. (1987). Bleaching teeth. Quintessence Pub. Co.
Fisher, G. (1911). The Bleaching of discolored teeth with H2O2. The Dental Cosmos, 53, 246–247.
Freedman, G., Gerlach, R. W., Greenwall, L. H. (2012). Contemporary esthetic dentistry. In Contemporary
Esthetic Dentistry, Mosby, 341–404.
Freire, A., Souza, E. M., de Menezes Caldas, D. B., Rosa, E. A., Bordin, C. F., de Carvalho, R. M., Vieira, S. (2009).
Reaction kinetics of sodium ascorbate and dental bleaching gel. Journal of Dentistry, 37(12), 932–936.
Garber, D. A. (1997). Dentist-monitored bleaching: a discussion of combination and laser bleaching. Journal
of the American Dental Association, 128(Suppl.), 26–30.
García-Godoy, F., Dodge, W. W., Donohue, M., O’Quinn, J. A. (1993). Composite resin bond strength after
enamel bleaching. Operative Dentistry, 18(4), 144–147.
Garcia-Lopez, M., Martinez-Blanco, M., Martinez-Mir, I., Palop, V. (2001). Amoxycillin-clavulanic acid-related
tooth discoloration in children. Pediatrics, 108(3), 819.
Gerlach, R. W., Barker, M. L., Karpinia, K., Magnusson, I. (2009). Single site meta-analysis of 6% hydrogen
peroxide whitening strip eectiveness and safety over 2 weeks. Journal of Dentistry, 37(5), 360–365.
Gerlach, R. W., Zhou, X. (2001). Vital bleaching with whitening strips: summary of clinical research on
eectiveness and tolerability. Journal of Contemporary Dental Practice, 2(3), 1–15.

133
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Gerlach, R. W., Zhou, X., Mcclanahan, S. F. (2002). Comparative response of whitening strips to a low peroxide
and potassium nitrate bleaching gel. American Journal of Dentistry, 15(spec. iss. 1), 19–23.
Gerlach, R. W., Barker, M. L. (2004). Professional vital bleaching using a thin and concentrated peroxide gel on
whitening strips: an integrated clinical summary. The Journal of Contemporary Dental Practice, 5(1), 1–17.
Giniger, M., MacDonald, J., Ziemba, S., Felix, H. (2005). The clinical perfrmance of professionally dispensed
bleaching gel with added amorphous calcium phosphate. Journal of the American Dental Association,
136(3), 383–392.
Gokay, O., Mujdeci, A., Algin, E. (2005). In vitro peroxide penetration into the pulp chamber from newer
bleaching products. International Endodontic Journal, 38(8), 516–520.
Goo, D. H., Kwon, T. Y., Nam, S. H., Kim, H. J., Kim, K. H., Kim, Y. J. (2004). The eciency of 10% carbamide
peroxide gel on dental enamel. Dental Materials Journal, 23(4), 522–527.
Greenwall, L., Fredman, G., Gordan, V. V. (2001). Bleaching techniques in restorative dentistry: an illustrated
guide. Martin Dunitz.
Hanks, C. T., Fat, J. C., Corcoran, J. F., Wataha, J. C. (1993). Cytotoxicity and dentin permeability of carbamide
peroxide and hydrogen peroxide vital bleaching materials, in vitro. Journal of Dental Research, 72(5),
931–938.
Hannig, C., Zech, R., Henze, E., Dorr-Tolui, R., Attin, T. (2003). Determination of peroxides in saliva-kinetics
of peroxide release into saliva during home-bleaching with Whitestrips® and Vivastyle®. Archives of Oral
Biology, 48(8), 559–566.
Hannig, C., Duong, S., Becker, K., Brunner, E., Kahler, E., Attin, T. (2007). Eect of bleaching on subsurface
micro-hardness of composite and a polyacid modied composite. Dental Materials, 23(2), 198–203.
Hansen, J. R., Frick, K. J, Walker, M. P. (2014). Eect of 35% sodium ascorbate treatment on microtensile
bond strength after nonvital bleaching. Journal of Endodontics, 40(10), 1668–1670.
Hatanaka, G. R., de Oliveira Abi-Rached, F., de Almeida-Júnior, A. A., dos Santos Cruz, C. A. (2013). Eect
of carbamide peroxide bleaching gel on composite resin exural strength and microhardness. Brazilian
Dental Journal, 24(3), 263–266.
Haywood, V. B., Heymann, H. O. (1989). Nightguard vital bleaching. Quintessence International, 20(3),
173–176.
Haywood, V. B., Heymann, H. O. (1991). Nightguard vital bleaching: how safe is it? Quintessence International,
22(7), 515–523.
Haywood, V. B. (1991). Overview and status of mouthguard bleaching. Journal of Esthetic and Restorative
Dentistry, 3(5), 157–161.

134
Vital Tooth Bleaching
Haywood, V. B. (1992). History, safety, and eectiveness of current bleaching techniques and applications
of the nightguard vital bleaching technique. Quintessence International, 23(7), 471–488.
Haywood, V. B. (1996). Achieving, maintaining, and recovering successful tooth bleaching. Journal of
Esthetic and Restorative Dentistry, 8(6), 31–38.
Haywood, V. B. (2000). Current status of nightguard vital bleaching. Compendium of Continuing Education
in Dentistry, 28(suppl.), 10–17.
Haywood, V. B. (2000). A comparison of at-home and inoce bleaching. Dent Today, 19(4), 44–53.
Haywood, V. B, Caughman, W. F., Frazier, K. B., Myers, M. L. (2001). Tray delivery of potassium nitrate-uoride
to reduce bleaching sensitivity. Quintessence International, 32(2), 105–109.
Haywood, V. B. (2001). Fundamentals of operative dentistry: a contemporary approach. Eds. Submit, J.B.,
Robbins, J.W., and Schwart, R.S. Chicago, Quintessence Pub. Co., 401–426.
He, L. B., Shao, M. Y., Tan, K., Xu, X., Li, J. Y. (2012). The eects of light on bleaching and tooth sensitivity
during in-oce vital bleaching: a systematic review and meta-analysis. Journal of Dentistry, 40(8), 644–653.
Joiner, A., Pickles, M. J., Matheson, J. R., Weader, E., Noblet, L., Huntington, E. (2002). Whitening toothpastes:
eects on tooth stain and enamel. International Dental Journal, 52(S5), 424–430.
Joiner, A. (2004). Tooth colour: a review of the literature. Journal of Dentistry, 32(suppl.), 3–12.
Joiner, A., Philpotts, C. J., Ashcroft, A. T., Laucello, M., Salvaderi, A. (2008). In vitro cleaning, abrasion and
uoride ecacy of a new silica based whitening toothpaste containing blue covarine. Journal of Dentistry,
36(suppl. 1), 32–37.
Joiner, A., Thakker, G. (2004). In vitro evaluation of a novel 6% hydrogen peroxide tooth whitening product.
Journal of Dentistry, 32(suppl.), 19–25.
Joshi, S. (2016). An overview of vital teeth bleaching. Journal of Interdisciplinary Dentistry, 6(1), 3–13.
Kashima-Tanaka, M., Tsujimoto, Y., Kawamoto, K., Senda, N., Ito, K., Yamazaki, M. (2003). Generation of free
radicals and/or active oxygen by light or laser irradiation of hydrogen peroxide or sodium hypochlorite.
Journal of Endodontics, 29(2), 141–143.
Kihn, P. W. (2007). Vital tooth whitening. Dental Clinics of North America, 51(2), 319–331.
Kishta-Derani, M., Neiva, G., Yaman, P, Dennison, J. (2007). In vitro evaluation of tooth-color change using
four paint-on tooth whiteners. Operative Dentistry, 32(4), 394–398.
Kugel, G., Aboushala, A., Zhou, X., Gerlach, R. W. (2002). Daily use of whitening strips on tetracycline-
stained teeth: comparative results after 2 months. Compendium of Continuing Education In Dentistry,
23(1A), 29–34.

135
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Lai, S. C., Tay, F. R., Cheung, G. S., Mak, Y. F., Carvalho, R. M., Wei, S. H., Toledano, M., Osorio, R., Pashley, D. H.
(2002). Reversal of compromised bonding in bleached enamel. Journal of Dental Research, 81(7), 477–481.
Lee, C. Q., Cobb, C. M., Zargartalebi, F., Hu, N. (1995). Eect of bleaching on microhardness, morphology,
and color of enamel. General Dentistry, 43(2), 158–160.
Lee, K. H., Kim, H. I., Kim, K. H., Kwon, Y. H. (2006). Mineral loss from bovine enamel by a 30% hydrogen
peroxide solution. Journal of Oral Rehabilitation, 33(3), 229–233.
Lima, D. A., Silva, A. L., Aguiar, F. H., Liporoni, P. C., Munin, E., Ambrosano, G. M., Lovadino, J. R. (2008). In
vitro assessment of the eectiveness of whitening dentifrices for the removal of extrinsic tooth stains.
Brazilian Oral Research, 22(2), 106–111.
Leonard, R. R. H., Garland, G. E., Eagle, J. C., Caplan, D. J. (2002). Safety issues when using a 16% carbamide
peroxide whitening solution. Journal of Esthetic and Restorative Dentistry, 14(6), 358–367.
Li, Q., Yu, H., Wang, Y. (2009). Colour and surface analysis of carbamide peroxide bleaching eects on the
dental restorative materials in situ. Journal of Dentistry, 37(5), 348–356.
Li, Y., Greenwall, L. (2013). Safety issues of tooth whitening using peroxide-based materials. British Dental
Journal, 215(1), 29–34.
Li, Y. (2003). Eect of light application on an in-oce bleaching gel. Journal of Dental Research, 82.
Lo, E. C. M., Wong, A. H. H., McGrath, C. (2007). A randomized controlled trial of home tooth-whitening
products. American Journal of Dentistry, 20(5), 315–318.
Luk, K., Tam, L., Hubert, M. (2004). Eect of light energy on peroxide tooth bleaching. Journal of the
American Dental Association, 135(2), 194–201.
Markowitz, K. (2010). Pretty painful: why does tooth bleaching hurt? Medical Hypotheses, 74(5), 835–840.
Matis, B. A., Cochran, M. A., Eckert, G. J., Matis, J. I. (2007). In vivo study of two carbamide peroxide gels
with dierent desensitizing agents. Operative Dentistry, 32(6), 549–555.
Matis, B. A., Mousa, H. N., Cochran, M. A., Eckert, G. J. (2000). Clinical evaluation of bleaching agents of
dierent concentrations. Quintessence International, 31(5), 303–310.
McEvoy, S. A. (1995). Removing Intrinsic stains from vital teeth by microabrasion and bleaching. Journal
of Esthetic and Restorative Dentistry, 7(3), 104–109.
McGuckin, R. S., Babin, J. F., Meyer, B. J. (1992). Alterations in human enamel surface morphology following
vital bleaching. The Journal of Prosthetic Dentistry, 68(5), 754–760.
Meireles, S. S., da Silva Dos Santos, I., Bona, A. D., Demarco, F. F. (2009). A double-blind randomized controlled
clinical trial of 10 percent versus 16 percent carbamide peroxide tooth-bleaching agents. Journal of the
American Dental Association, 140(9), 1109–1117.

136
Vital Tooth Bleaching
Nathoo, S. A. (1997). The chemistry and mechanisms of extrinsic and intrinsic discoloration. Journal of
the American Dental Association, 128(suppl. 4), 6–10.
Odioso, L. L., Gibb, R. D., Gerlach, R. W. (2000). Impact of demographic, behavioral, and dental care
utilization parameters on tooth color and personal satisfaction. Compendium Of Continuing Education
In Dentistry, 29(suppl.), 35–41.
Ontiveros, J. C. (2011). In-oce vital bleaching with adjunct light. Dental Clinics of North America, 55(2),
241–253.
de Paula, E. A., Nava, J. A., Rosso, C., Benazzi, C. M., Fernandes, K. T., Kossatz, S., Loguercio, A. D., Reis, A.
(2015). In-oce bleaching with a two- and seven-day intervals between clinical sessions: a randomized
clinical trial on tooth sensitivity. Journal of Dentistry, 43(4), 424–429.
Petersson, L. G. (2013). The role of uoride in the preventive management of dentin hypersensitivity and
root caries. Clinical Oral Investigations, 17(suppl.1), 63–71.
Pinto, C. F., de Oliveira, R., Cavalli, V., Giannini, M. (2004). Peroxide bleaching agent eects on enamel
surface microhardness, roughness and morphology. Brazilian Oral Research, 18(4), 306–311.
Poulsen, S, Errboe, M., Mevil, Y. L., Glenny, A. (2006). Potassium containing toothpastes for dentine
hypersensitivity. Cochrane Database of Systematic Reviews, 19(3), 1-16, CD001476.
Rodrigues, J. A., Oliveira, G. P. F., Amaral, C. M. (2007). Eect of thickener agents on dental enamel
microhardness submitted to at-home bleaching. Brazilian Oral Research, 21(2), 170–175.
Rosenstiel, S. F., Gegau, A. G., Johnston, W. M. (1996). Randomized clinical trial of the ecacy and safety
of a home bleaching procedure. Quintessence International, 27(6), 413–424.
Sagel, P. A., Odioso, L. L., McMillan, D. A., Gerlach, R. W. (2000). Vital tooth whitening with a novel hydrogen
peroxide strip system: design, kinetics, and clinical response. Compendium Of Continuing Education In
Dentistry, 29(suppl.), 10–15.
Sánchez, A. R., Rogers, R. S., Sheridan, P. J. (2004). Tetracycline and other tetracycline-derivative staining
of the teeth and oral cavity. International Journal of Dermatology, 43(10), 709–715.
Sherwood, I. (2010). Fluorosis varied treatment options. Journal of Conservative Dentistry, 13(1), 47.
da Silva Machado J., Cândido, M. S., Sundfeld, R. H., de Alexandre, R. S., Cardoso, J. D., Sundefeld, M. L.
(2007). The inuence of time interval between bleaching and enamel bonding. Journal of Esthetic and
Restorative Dentistry, 19(2), 111–118.
Strassler, H. E. (2006). Vital tooth bleaching: an update. Continuing Education Insert, 4, 1–8
Şişmanoğlu, S., Gümüştaş, B., Efes, B. G. (2013) The impact of uoride or ozone gas before vital tooth
bleaching on enamel surface roughness. European Oral Research, 47(1) , 1–7.

137
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Soares, D. G., Basso, F. G., Scheel, D. S., Hebling, J., de Souza Costa, C. A. (2015). Responses of human
dental pulp cells after application of a low-concentration bleaching gel to enamel. Archives of Oral
Biology, 60(9), 1428–1436.
Costa, C. A., Riehl, H., Kina, J. F., Sacono, N. T., Hebling, J. (2010). Human pulp responses to in-oce tooth
bleaching. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology, 109(4), 59–64.
Sulieman, M. (2004). An overview of bleaching techniques: I. history, chemistry, safety and legal aspects.
Dental Update, 31(10), 612–616.
Sulieman, M. (2005). An overview of bleaching techniques: 2. night guard vital bleaching and non-vital
bleaching. Dental Update, 32(1), 39–46.
Sulieman, M., Addy, M., MacDonald, E., Rees, J. S. (2005). The bleaching depth of a 35% hydrogen peroxide
based in-oce product: a study in vitro. Journal of Dentistry, 33(1), 33–40.
Sulieman, M., Addy, M., Rees, J. S. (2003). Development and evaluation of a method in vitro to study the
eectiveness of tooth bleaching. Journal of Dentistry, 31(6), 415–422.
Sulieman, M. (2008). An overview of tooth-bleaching techniques: chemistry, safety and ecacy.
Periodontology 2000, 48(1), 148–169.
Swift, E. J. and Perdigão, J. (1998). Eects of bleaching on teeth and restorations. Compendium Of
Continuing Education In Dentistry, 19(8), 815–820
Tam, L. (1999). Clinical trial of three 10% carbamide peroxide bleaching products. Journal (Canadian
Dental Association), 65(4), 201–205.
Tam, L. (2001). Eect of potassium nitrate and uoride on carbamide peroxide bleaching. Quintessence
International, 32(10), 766–770.
Tarbet, W. J., Buckner, A., Stark, M. M., Fratarcangelo, P. A., Augsburger, R. (1981). The pulpal eects of
brushing with a 5 percent potassium nitrate paste used for desensitization. Oral Surgery, Oral Medicine,
Oral Pathology, 51(6), 600–602.
Tay, L. Y., Kose, C., Loguercio, A. D., Reis, A. (2009). Assessing the eect of a desensitizing agent used before
in-oce tooth bleaching. Journal of the American Dental Association, 140(10), 1245–1251.
Thylstrup, A., Fejerskov, O. (1978). Clinical appearance of dental uorosis in permanent teeth in relation
to histologic changes. Community Dentistry and Oral Epidemiology, 6(6), 315–328.
Titley, K. C., Torneck, C. D., Smith, D. C., Chernecky, R., Adibfar, A. (1991). Scanning electron microscopy
observations on the penetration and structure of resin tags in bleached and unbleached bovine enamel.
Journal of Endodontics, 17(2), 72–75.
Titley, K. C., Torneck, C. D., Smith, D. C. (1988). The eect of concentrated hydrogen peroxide solutions on
the surface morphology of human tooth enamel. Journal of Endodontics, 14(2), 69–74.

138
Vital Tooth Bleaching
Toko, T., Hisamitsu, H. (1993). Shear bond strength of composite resin to unbleached and bleached human
dentine. Asian Journal of Aesthetic Dentistry, 1(1), 33–36.
Torres, C. R., Batista, G. R., César, P. D., Barcellos, D. C., Pucci, C. R., Borges, A. B. (2009). Inuence of the
quantity of coloring agent in bleaching gels activated with led/laser appliances on bleaching eciency.
The European Journal of Esthetic Dentistry, 4(2), 178–186.
Turkun, M., Kaya, A. D. (2004). Eect of 10% sodium ascorbate on the shear bond strength of composite
resin to bleached bovine enamel. Journal of Oral Rehabilitation, 31(12), 1184–1191.
Turkun, M., Celik, E. U., Kaya, A. D., Arici, M. (2009). Can the hydrogel form of sodium ascorbate be used
to reverse compromised bond strength after bleaching? The Journal of Adhesive Dentistry, 11(1), 35–40.
Unlu, N., Cobankara, F. K., Ozer, F. (2008). Eect of elapsed time following bleaching on the shear bond
strength of composite resin to enamel. Journal of Biomedical Materials Research Part B. Applied Biomaterials,
84B(2), 363–368.
Ushigome, T., Takemoto, S., Hattori, M., Yoshinari, M., Kawada, E., Oda, Y. (2009). Inuence of peroxide
treatment on bovine enamel surface - cross-sectional analysis. Dental Materials Journal, 28(3), 315–323.
Vilhena, K. F. B., Nogueira, B. C. L., Fagundes, N. C. F., Loretto, S. C., Angelica, R. S., Lima, R. R., Silva E., Souza
M. H. J. (2019). Dental enamel bleached for a prolonged and excessive time: morphological. PLos One,
14(4), e0214948.
Viscio, D., Gaar, A., Fakhry-Smith, S., Xu, T. (2000). Present and future technologies of tooth whitening.
Compendium of Continuing Education In Dentistry, 28(suppl.), 36–43.
Vohra, F. A., Kasah K. (2014). Inuence of bleaching and antioxidant agent on microtensile bond strength
of resin based composite to enamel. Saudi Journal for Dental Research, 5(1), 29–33.
Walsh, L. J. (2000). Safety issues relating to the use of hydrogen peroxide in dentistry. Australian Dental
Journal, 45(4), 257–269.
Watts, A., Addy, M. (2001). Tooth discolouration and staining: a review of the literature. British Dental
Journal, 190(6), 309–316.
Yap, A. U. J., Wattanapayungkul, P. (2002). Eects of in-oce tooth whiteners on hardness of tooth-colored
restoratives. Operative Dentistry, 27(2), 137–141.
Yu, H., Pan, X., Lin, Y., Li, Q., Hussain, M., Wang, Y. (2009). Eects of carbamide peroxide on the staining
susceptibility of tooth-colored restorative materials. Operative Dentistry, 34(1), 72–82.
Yu, H., Li, Q., Lin, Y., Buchalla, W., Wang, Y. (2010). Inuence of carbamide peroxide on the exural strength
of tooth-colored restorative materials: an in vitro study at dierent environmental temperatures. Operative
Dentistry, 35(3), 300–307.

139
JOURNAL OF HEALTH SCIENCES
A. J. Health Sci.
Yu, H., Li, Q., Cheng, H., Wang, Y. (2011). The eects of temperature and bleaching gels on the properties
of tooth-colored restorative materials. Journal of Prosthetic Dentistry, 105(2), 100–107.
Yu, H., Li, Q., Hussain, M., Wang, Y. (2008). Eects of bleaching gels on the surface microhardness of tooth-
colored restorative materials in situ. Journal of Dentistry, 36(4), 261–267.
Yu, H., Zhang, C. Y., Cheng, S. L., Cheng, H. (2015). Eects of bleaching agents on dental restorative materials:
a review of the literature and recommendation to dental practitioners and researchers. Journal of Dental
Sciences, 10(4), 345–351.
Zantner, C., Derdilopoulou, F., Martus, P., Kielbassa, A. M. (2006). Randomized clinical trial on the ecacy
of 2 over-the-counter whitening systems. Quintessence International, 37(9), 695–706.