Case Report
New Parameter for In-Office Dental Bleaching

Cristina Dupim Presoto,1 Janaina Freitas Bortolatto,1

Priscila Petrucelli Freire de Carvalho,1 Tamara Carolina Trevisan,1

Michael Christopher Floros,2 and Osmir Batista de Oliveira Junior1

1Department of Restorative Dentistry, Araraquara Dental School, Universidade Estadual Paulista (UNESP),
1680 Humaitá Street, 14801-903 Araraquara, SP, Brazil
2Departments of Physics & Astronomy and Chemistry, Trent Centre for Biomaterials Research, Trent University,
Peterborough, ON, Canada K9J 7B8

Correspondence should be addressed to Cristina Dupim Presoto; crispresoto@hotmail.com

Received 29 March 2016; Accepted 17 May 2016

Academic Editor: Michelle A. Chinelatti

Copyright © 2016 Cristina Dupim Presoto et al.This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in anymedium, provided the originalwork is properly cited.

Dental bleaching is considered a conservative and biologically safe treatment for discolored teeth. Despite this, one of the major
undesirable effects of bleaching is dentin sensitivity whichmay occur during and after treatment. To address these sensitivity issues,
new dental bleaching preparations with lower concentrations of hydrogen peroxide (H

2
O
2
) have recently been introduced to the

market.This paper presents a clinical case report of a 20-year-old female patient admitted to the Araraquara Dental School, UNESP,
Brazil.The patient underwent dental bleaching using one of the new products with reduced hydrogen peroxide concentration, Lase
Peroxide Lite 6%, a 6% H

2
O
2
gel containing titanium oxide nanoparticles doped with nitrogen (6% H

2
O
2
/N-doped TiO

2
).

1. Introduction

The demand for aesthetic dentistry has increased contin-
uously [1–4], and the smile’s appearance has become an
important part of the social attractiveness of a person and
their interactive communication skill [1, 2, 4, 5].

Currently, dental bleaching has been recognized as an
effective method for the treatment of discolored teeth, being
considered a conservative and biologically safe type of treat-
ment [4, 6–9].

Hydrogen peroxide (H
2
O
2
) is a chemical substance with

high oxidative power and is the most widely used agent for
in-office teeth whitening at concentrations ranging mainly
from 25 to 35% [10–13]. Peroxide agents are highly unstable
and when in contact with the tissue, they dissociate into
water, oxygen, and free radicals, the latter accounting for
the observed bleaching effect due to their ability to oxidize
organic pigments [9]. It is known that the diffusion of H

2
O
2

through the dentin depends on the concentration of the gel,
the period of time that the agent is in contact with the tooth
[13], and the thickness of the dental structure [8, 14].

One of the major undesirable effects of bleaching is tooth
sensitivity [4, 7, 9, 12, 13, 15–18] that occurs during and
after the treatment and may represent a degree of biological
damage to the dentin-pulp complex [4, 7, 9, 13, 15–17]. There
are many factors that are known to increase sensitivity, such
as high concentrations of H

2
O
2
, high enamel permeability,

prolonged use of bleaching agents, heat during application
through accelerator lamps, and differences in the structural
morphology of enamel and dentin with pores which facilitate
the infiltration of bleaching [8, 12, 15, 16]. Sensitivity issues
have led some manufacturers to release bleaching gels with
lower concentrations of H

2
O
2
in order to minimize the side

effects produced by peroxide radicals [9, 13, 17].
Aiming to increase both efficacy and safety, new bleach-

ing agents with lower concentrations of H
2
O
2
based on the

catalytic action of a nanoparticle semiconductor additive
such as titanium dioxide (TiO

2
) activated by light sources

[9, 16–20] are now entering the market [4, 9, 13, 16–
20]. A significant reduction in the sensitivity of bleaching
treatments which use nitrogen doped titanium dioxide and
15% H

2
O
2
concentration has been reported in the literature

Hindawi Publishing Corporation
Case Reports in Dentistry
Volume 2016, Article ID 6034757, 4 pages
http://dx.doi.org/10.1155/2016/6034757



2 Case Reports in Dentistry

Figure 1: Initial picture taken with calibration block.

Figure 2: Gingival barrier properly applied and light-cured.

[8, 9, 16–18]. Nevertheless, bleaching agents with 6% H
2
O
2
/

N-doped TiO
2
are innovative and significantly lower in

peroxide concentration and, to our knowledge, there are few
clinical studies evaluating in-office tooth bleaching with
agents at this concentration [17, 18]. Thus, this study aims to
present a case report using this new product.

2. Case Presentation

A female patient, PPFC, 20 years old, attended the Operative
Dentistry Clinic at AraraquaraDental School, UNESP, Brazil,
and reported dissatisfactionwith the aesthetics of her anterior
teeth. Despite the midline diastema between central incisors,
the factor that most bothered her was the color of her teeth.
During the clinical exam, there were no factors observed
which would contraindicate the use of tooth bleaching. As
the patient was young, we decided to use a bleaching agent
with a minimal H

2
O
2
concentration.We used a new product,

Lase Peroxide Lite 6% (6% H
2
O
2
/N-doped TiO

2
) (DMC

Equipment, São Carlos, SP, Brazil), which is activated by a
light source. The light source used was a Whitening Lase II
(DMC Equipment, São Carlos, SP, Brazil), a new type of in-
office photocatalytic equipment composed of six violet LEDs
(405 nm wavelength) and three infrared lasers (808 nm).

Before beginning the treatment, initial photography with
a ceramic block for calibration was performed and retained
for subsequent analysis using ScanWhite, a specific software
program for the objective assessment of tooth bleaching
levels based on computational processing of digital images
(Figure 1). Subsequently, professional dental prophylaxis was
performed with a Robinson brush with a pumice and water
paste. A gingival barrier (Lase Protect, DMC, São Carlos, SP,
Brazil) was then applied and light-cured for 10 seconds for
each dental element (Figure 2).

Figure 3: Bleaching gel applied to the buccal surface of the upper
and lower teeth.

Figure 4: Final picture taken with calibration block.

The bleaching agent was mixed and applied in homoge-
neous layers on the buccal surfaces of the upper and lower
anterior teeth (Figure 3). The 6% H

2
O
2
/N-doped TiO

2
gel is

provided in two phases, a peroxide and a thickener, which
should be mixed in proportions of 3 drops of peroxide for 1
drop of thickener. In this case, for whitening the upper and
lower arches until the premolars region, we used a total of
18 drops of peroxide and 6 drops of thickener. After the gel’s
application, it was kept in contact with dental surface for 12
minutes and photocatalyzed by LED/laser light, alternating
the irradiation between the upper and lower arches every
minute. Afterwards, the bleaching gel was removed and a new
application sequence was performed. Three clinical sessions
were held with two application cycles of the bleaching agent
in each of them and a 7-day interval between the sessions.

One week following the end of the bleaching treatment,
a new photography session was performed with the same
calibration block (Figure 4).The initial and final images were
compared in ScanWhite to determine how much the teeth
responded to the whitening procedure. The images were first
transmitted to the software and a calibration was performed.
Next, for each picture, an areawas selected in themiddle third
of labial surface of the anterior teeth. The result showed 22
tones of whitening for the upper right central incisor and 50
tones for the right canine (Figure 5).The patient reported that
she was very satisfied with the final color of her teeth.

Tooth sensitivity was measured by a visual analogue scale
(VAS), which provides a range of scores from 0 to 100, where
0 represents no pain and 100 represents extreme pain. At
the end of each clinic session, the patient was asked to mark
on the scale their perceived sensitivity both during and after
the session. She reported sensitivity only during the first
application in the second session and this was classified as



Case Reports in Dentistry 3

Baseline 1st evaluation 2nd evaluation

Right central incisor
Left central incisor
Right canine

Left canine
General results

Figure 5: Overall result of bleaching.

low, with an intensity of 20% in a shock sensation and with
a 1-second duration.

3. Discussion

The presence of sensitivity to bleaching treatments with high
concentration gels and the search for an alternative with both
efficacy and safety were the main reasons why bleaching
agents with lower concentrations of H

2
O
2
were introduced

to the market [4, 8, 13, 17, 18]. Initially, it was believed that
a high concentration gel and long contact time with dental
structure would be required to obtain greater efficacy with
bleaching procedures [9, 21]. Nonetheless, the use of 15%
H
2
O
2
/TiO
2
photocatalyzed by LED was recently reported

and demonstrated that, besides having lower sensitivity com-
pared to products with 35% concentration, this preparation
also provided greater bleaching efficacy [8, 9, 16, 17, 20]. We
also observed this finding in the clinical case presented here
using a preparation with only 6% H

2
O
2
.

The presence of N-doped TiO
2
semiconductor allows

a reduction in the required concentration of H
2
O
2
, which

improves the biocompatibility of the final product by sig-
nificantly reducing dental sensitivity during and after the
procedure, directly increasing the safety of thewhitening pro-
cedure [9, 17–19]. By incorporatingN-doped TiO

2
nanoparti-

cles, it is necessary to photocatalyze the gel with a light source
in order to improve its action. This new class of bleaching
agents is safer and effective for promoting bleaching with
a reduced concentration of free radical peroxides, thereby
minimizing damage to the tooth structure [22].

In a clinical study using a 6% H
2
O
2
varnish system

for in-office whitening, da Mata and Marques [10] reported
that none of the patients showed any sensitivity, which was
a common side effect upon using gels with high peroxide
concentrations. By using a 6% H

2
O
2
varnish, Calatayud et

al. [23] also demonstrated that the application of the gel
showed significant clinical efficacy when applied to in-office
bleaching and also when applied by patients themselves at
home.

In the clinical case described in this paper, upon com-
paring the results before and after the bleaching procedure,
the choice for central incisors and canines teeth was done to
ensure a more homogeneous sample, as central and lateral
incisors usually have the same color and, together, could
distort the results of the hemiarch’s mean score [23–25]. In
Figure 5, a major color alteration is observed for the canines
when compared to central incisors. The results showed that
the use of these new bleaching gels provides color alter-
ation needed for patient satisfaction in addition to lowering
dental sensitivity. Therefore, this case reported a successful
bleaching treatment for young patients, combining the great
aesthetic results, as desired by patients, and also improved
biocompatibility and safety from a lower concentration of
bleaching gel.

Consent

The authors declare that the patient gave her informed
consent for the case report to be published.

Competing Interests

The authors declare that there is no conflict of interests
regarding the publication of this paper.

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