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Efficacy of products for bleaching and whitening under orthodontic brackets

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Introduction Many patients wearing orthodontic appliances request alterations in the shade of their teeth during orthodontic treatment. Objective This study aimed to evaluate the efficacy of different products for bleaching and whitening under orthodontic brackets. Methods Seventy bovine incisors were randomly divided into five groups (n = 14): C) non-whitening toothpaste (control); WTsi) hydrated silica whitening toothpaste; WThp) 2% hydrogen peroxide whitening toothpaste; OB) in-office bleaching; and HB) at-home bleaching. Two buccal surface areas were evaluated using the Easyshade spectrophotometer: under the metal bracket (experimental) and around the bracket (control). The paired t-test, ANOVA, and Tukey tests were applied for statistical analysis. Results Intragroup comparisons showed that in groups C, WThp and HB, there were statistically significant differences in the enamel color changes (ΔEab) between under and around the bracket areas (C - under bracket = 7.97 ± 2.35, around bracket = 2.86 ± 0.81, p< 0.01; WThp - under bracket = 4.69 ± 2.98, around bracket = 2.05 ± 1.41, p< 0.01; HB - under bracket = 7.41 ± 2.89, around bracket: 9.86 ± 3.32, p= 0.02). Groups WTsi, OB and HB presented similar perception of tooth whiteness (ΔWID) between the tested areas. Intergroup comparisons demonstrated that under the bracket area, the color change (ΔEab) was similar for all groups, except WThp (C = 7.97 ± 2.35; WTsi = 8.54 ± 3.63; WThp = 4.69 ± 2.98; OB = 9.31 ± 4.32; HB = 7.41 ± 2.89; p< 0.01). Conclusions The dental color changes were effective for the products tested in groups WTsi, OB and HB in the presence of metallic orthodontic brackets. Keywords: Tooth bleaching; Toothpastes; Tooth bleaching agents; Orthodontic brackets
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Dental Press J Orthod. 2022;27(5):e2220325
https://doi.org/10.1590/2177-6709.27.5.e2220325.oar
Célia Regina Maio PINZAN-VERCELINO1
https://orcid.org/0000-0002-5419-0079
Suellen Nogueira Linares LIMA2
https://orcid.org/0000-0003-1156-2888
Fernando Félix de Jesus Vieira PEREIRA2
https://orcid.org/0000-0003-4265-9949
Júlio de Araújo GURGEL3
https://orcid.org/0000-0003-4205-0965
Gisele Rodrigues da SILVA4
https://orcid.org/0000-0002-9358-1339
Karina Maria Salvatore de FREITAS5
https://orcid.org/0000-0001-9145-6334
ORIGINAL ARTICLE
Volume 27 - Number 5 - Online
Efficacy of products for bleaching and
whitening under orthodontic brackets
(1) Centro Universitário Uningá, Departamento de Odontologia (Maringá/PR, Brazil). (2) Universidade Ceuma, Departamento
de Odontologia (São Luís/MA, Brazil). (3) Universidade Estadual de São Paulo (UNESP) (Marília/SP, Brazil). (4) Universidade
Federal de Uberlândia, Escola de Odontologia, Departamento de Dentística Operatória e Materiais Odontológicos
(Uberlândia/MG, Brazil). (5) Centro Universitário Uningá, Departamento de Odontologia (Maringá/PR, Brazil).
Submitted: August 05, 2020  Revised and accepted: November 24, 2021
cepinzan@hotmail.com
How to cite: Pinzan-Vercelino CRM, Lima SNL, Pereira FFJV, Gurgel JA, Silva GR, Freitas KMS. Efficacy of products
for bleaching and whitening under orthodontic brackets. Dental Press J Orthod. 2022;27(5):e2220325.
Dental Press J Orthod. 2022;27(5):e2220325
Pinzan-Vercelino CRM, Lima SNL, Pereira FFJV, Gurgel JA, Silva GR, Freitas KMS —
Efficacy of products for bleaching and whitening under orthodontic brackets
2
ABSTRACT
Introduction: Many patients wearing orthodontic appliances
request alterations in the shade of their teeth during orthodon-
tic treatment. Objective: This study aimed to evaluate the ef-
ficacy of different products for bleaching and whitening under
orthodontic brackets. Methods: Seventy bovine incisors were
randomly divided into five groups (n = 14): C) non-whitening
toothpaste (control); WTsi)hydrated silica whitening tooth-
paste; WThp) 2% hydrogen peroxide whitening toothpaste;
OB)in-office bleaching; and HB)at-home bleaching. Twobuc-
cal surface areas were evaluated using the Easyshade spec-
trophotometer: under the metal bracket (experimental) and
around the bracket (control). The paired t-test, ANOVA, and
Tukey tests were applied for statistical analysis. Results: In-
tragroup comparisons showed that in groups C, WThp and HB,
there were statistically significant differences in the enamel
color changes (ΔEab) between under and around the bracket ar-
eas (C- under bracket = 7.97 ± 2.35, around bracket = 2.86 ± 0.81,
p < 0.01; WThp - under bracket = 4.69 ± 2.98, around brack-
et = 2.05±1.41, p < 0.01; HB- under bracket = 7.41 ± 2.89, around
bracket: 9.86 ±3.32, p = 0.02). Groups WTsi, OB and HB pre-
sented similar perception of tooth whiteness (ΔWID) between
the tested areas. Intergroup comparisons demonstrated that
under the bracket area, the color change (ΔEab) was similar
for all groups, except WThp (C = 7.97 ± 2.35; WTsi = 8.54 ± 3.63;
WThp = 4.69 ± 2.98; OB = 9.31 ± 4.32; HB = 7.41 ± 2.89; p < 0.01).
Conclusions: The dental color changes were effective for the
products tested in groups WTsi, OB and HB in the presence of
metallic orthodontic brackets.
Keywords: Tooth bleaching. Toothpastes. Tooth bleaching
agents. Orthodontic brackets.
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RESUMO
Introdução: Durante o tratamento ortodôntico, muitos pacien-
tes solicitam, também, alteração na cor dos seus dentes. Objetivo:
O presente estudo avaliou diferentes produtos clareadores e
branqueadores, quanto à sua eficácia sob os braquetes ortodôn-
ticos. Métodos: 70 incisivos bovinos foram aleatoriamente divi-
didos em cinco grupos (n = 14): C)dentifrício não branqueador
(controle); WTsi) dentifrício branqueador com sílica hidratada;
WThp)dentifrício branqueador com peróxido de hidrogênio a 2%;
OB)clareamento no consultório e HB)clareamento caseiro. Usan-
do um espectrofotômetro Easyshade, foram avaliadas duas áreas
na superfície vestibular dos dentes: sob o braquete (experimental)
e ao redor do braquete (controle). Para análise estatística, foram
usados ostestest pareado, ANOVA e Tukey. Resultados: As com-
parações intragrupos demonstraram que, nos grupos C, WThp e
HB, ocorreram diferenças estatisticamente significativas nas al-
terações de cor do esmalte(ΔEab) entre as áreas sob o braquete e
ao redor do braquete (C:sob o braquete = 7,97 ± 2,35, ao redor do
braquete = 2,86 ± 0,81, p < 0,01; WThp: sob o braquete = 4,69 ± 2,98,
ao redor do braquete = 2,05 ± 1,41, p < 0,01; HB: sob o braque-
te = 7,41 ± 2,89, ao redor do braquete = 9,86 ± 3,32, p = 0,02). Osgru-
pos WTsi, OB e HB demonstraram semelhanças na percepção do
clareamento(ΔWID) entre as áreas avaliadas. As comparações in-
tergrupos demonstraram que, nas áreas sob os braquetes, as al-
terações de cor (ΔEab) foram semelhantes para os grupos, com exce-
ção do WThp (C = 7,97 ± 2,35; WTsi = 8,54 ± 3,63; WThp = 4,69 ± 2,98;
OB = 9,31 ± 4,32; HB = 7,41 ± 2,89; p < 0,01). Conclusões: As altera-
ções na cor dos dentes foram efetivas para os procedimentos tes-
tados nos grupos WTsi, OB e HB na presença de braquetes metá-
licos ortodônticos.
Palavras-chave: Clareamento dental. Cremes dentais. Agen-
tes clareadores dentais. Braquetes ortodônticos.
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INTRODUCTION
Dental bleaching and alignment are the majority of complaints
from patients who attend dental offices.1-3 Besides the aesthetic
benefits, dental color and position changes have also been
correlated with individuals’ social perception, including more
positive judgments related to social competence and appeal,
intellectual ability, and relationship satisfaction.1,4
Many orthodontic patients request dental bleaching during
orthodontic treatment,5 to simultaneously achieve the desired
dental color and position. Usually, dissatisfaction with the color
of teeth increases when the crowding is solved.2
Dental bleaching and whitening are different processes. Dental
bleaching involves the application of gels containing hydrogen per-
oxide or carbamide peroxide on the tooth surface. Theperoxide
diffuses through the enamel and dentin, producing free radicals
that react with the intrinsic pigments, making the teeth appear
whiter.6,7 A recent study suggested that hydrogen peroxide might
whiten normal dentin by oxidizing the benzene ring of aromatic
amino acids in dentin phosphoprotein, the main noncollagenous
protein located in the organic-inorganic interface, responsible for
the fluorescence and color of normal dentin.8 On the other hand,
dental whitening consists of the removal and control of extrin-
sic tooth stains.7 Currently, many whitening products, with the
promise of rapid and convenient color alteration, are available
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on the market, including whitening toothpastes.7,9,10 Whitening
toothpastes have become popular due to low costs, unrestricted
selling, ease of use, and high availability.7,11
Most whitening products act in one of these mechanisms: chemical
(the use of peroxides for tooth bleaching) or mechanical (removal
of extrinsic stains through abrasive action).7,12 Toothpastes that
act using a mechanical mechanism contain abrasives that only
remove the extrinsic stains, instead of changing the tooth color, as
is observed in a real bleaching action. Some whitening toothpastes
have included peroxide in their formulations; however, the efficacy
of peroxide from toothpaste is questioned regarding the concen-
tration and exposure time during toothbrushing.13
Previous clinical14,15 and laboratory16-19 studies have shown color
alteration under the bracket area using bleaching agents. However,
even with the increasing presence of whitening toothpastes on the
market, the authors are unaware of a study that has been conducted
to test their efficacy on teeth with bonded brackets. Therefore,
the present study aimed to evaluate different products’ efficacy
for bleaching and whitening under orthodontic brackets. The null
hypothesis tested was that there would be no differences in color
change when hydrated silica whitening toothpaste; 2% hydrogen
peroxide whitening toothpaste; in-office dental bleaching using 35%
hydrogen peroxide; and at-home bleaching using 22% carbamide
peroxide procedures are applied on teeth with bonded brackets.
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MATERIAL AND METHODS
The local Animal Ethics Research Committee (CEUA-UNICEUMA,
São Luís/MA, Brazil) approved this in vitro investigation (protocol
0029016). The sample size calculation was based on data previ-
ously described,15,20 using the dental color change (ΔEab) as a refer-
ence variable. The parameters used were: 95% confidence level,
power of 80%, standard deviation of 2.3 ΔEab, and a minimum dif-
ference of 2.7 ΔEab between the means (G*Power software, ver-
sion 3.1.3; Franz Faul, University of Kiel, Kiel, Schleswig-Holstein,
Germany). The minimum number of specimens was determined
to be 12 per group, and 20% was added to this value to increase
the power, thus resulting in 14 teeth per group.
Seventy experimental units were obtained from bovine incisors
aged between 24 and 30 months, and were stored in a refriger-
ated 1% chloramine–T solution, ph7, for 30 days. The following
criteria for tooth selection were used: intact buccal enamel, with
no cracks, no abrasion, or any other crown defect, and similar
size and shade (A3, determined by comparison with a value-ori-
ented shade guide – Vita Toothguide 3D Master; VITA Zahnfabrik,
Bad Säckingen, Bade-Württemberg, Germany). Themorphologi-
cal enamel conditions were evaluated by two researchers, using
a simple magnifying glass. Only in cases of agreement, the teeth
were selected. The researchers inspected 120 teeth and selected
70 from this set. The roots and pulp chamber of the teeth were
removed. The pulp chamber was accessed and extended using a
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conical diamond tip. The dental pulp and debris were removed
using a dental curette and air/water jets. Afterward, the bovine
incisors were stored for 7 days in distilled water.
One matrix was made for each tooth, using high-viscosity sil-
icone, to standardize the color measurement area, and guide
the bracket bonding. In the matrix, two vertically adjacent cir-
cular windows were located close to the center of the crown, on
the buccal surface of the teeth (Fig1): one experimental area
(under the bracket) and one control area (around the bracket).
They were configured using a circular metal-cutting device
measuring 6 mm in diameter (Biopsy Punch, Miltex; York, PA,
USA), corresponding to the diameter of the spectrophotometer
probe (Easyshade Advance 4.0; Vident, Brea, CA, USA).14,15,21,22
A single calibrated operator performed the bonding procedure.
Before brackets bonding, the teeth received dental screening and
dental prophylaxis, using pumice and a rubber cup with a low-speed
handpiece. With the matrix installed on the buccal surface of the
teeth, at the circular opening of the experimental area, 37% phos-
phoric acid gel was applied for 30s, followed by rinsing for 30s, and
drying for 15s. The Transbond XT primer (3M Unitek Orthodontic
Products, Monrovia, CA, USA) was applied, followed by a brief air
spray and light-curing for 20s. Metal brackets (maxillary central
incisor, Standard Edgewise, 0.022 x 0.030-in slot; Morelli, Sorocaba/
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Figure 1: The silicone matrix
made individually for each
tooth, to standardize the col-
or measurement area and
guide the brackets bonding.
SP,Brazil) were bonded on the prepared surface using Transbond
XT light-cure composite resin (3M Unitek Orthodontic Products,
Monrovia, CA, USA). The brackets were positioned at the center of
the experimental area, and held down with 300g force for 10s, using
a tensiometer. Before light-activation, the matrix was removed,
and the excess material was removed using an exploratory probe.
Thecuring process was performed using a LED light-curing unit set
at 1400 mW/cm2 (VALO®, Ultradent, South Jordan, UT, EUA) for 10 s,
5 s on each side (mesial and distal). Thelight intensity was mea-
sured by a radiometer (Demetron LED radiometer, Kerr Sybron
Dental Specialties; Middleton, WI, USA).
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The specimens were numbered and then equally (n=14) and
randomly (Random.org Integer Generator; http://www.ran-
dom.org) divided into five groups (Table 1): C –non-whitening
toothpaste (Colgate Tripla Ação, Colgate-Palmolive, SP, Brazil);
WTsi – hydrated silica whitening toothpaste (Colgate Optic
White, Colgate-Palmolive, NY, USA); WThp –2% hydrogen per-
oxide whitening toothpaste (Colgate Luminous White Advanced
Expert, Colgate-Palmolive, Gua, Guanajuato, Mexico); OB–in-of-
fice bleaching (Whiteness HP 35%, FGM, SC, Brazil); and
HBat-home bleaching (Whiteness Simple 22% FGM, SC, Brazil).
Toothbrushing simulations were made using a custom-made
automated toothbrushing machine (Biopdi XY, São Carlos/SP,
Brazil) with suspensions prepared with the testing toothpastes
and distilled water, in a 1:2 ratio, in weigh11,12 (course: 3.8 cm;
velocity: 356 rpm). Soft orthodontic toothbrushes were used
(Oral-B Orthodontic Toothbrush 35, P&G, USA). Controlled
time, pressure, and temperature (36 ± 1ºC) were applied.
Table 1: Testing groups: commercial name, relevant ingredients and manufacturer descriptions.
Group Commercial name Relevant ingredients Manufacturer
C Colgate Tripla Ação Sodium monouorophosphate at
0.76% (0.14% w/v uoride ion)
Colgate-Palmolive,
SP, Brazil
WTsi Colgate Optic White Hydrated silica, tetrapotassium pyrophos-
phate, pentasodium triphosphate
Colgate-Palmolive,
NY, USA
WThp Colgate Luminous White
Advanced Expert
Hydrogen peroxide at 2%, sodium monouo-
rophosphate at 0.76%
Colgate-Palmolive,
Gua, Mexico
OB Whiteness HP 35% Hydrogen peroxide at 35% FGM, SC, Brazil
HB Whiteness Simple 22% Carbamide peroxide at 22% FGM, SC, Brazil
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Thespecimens were brushed twice a day for 15 days (500 cycles
in each brushing), totalizing 15,000 cycles of circular mechanical
brushing. After each brushing cycle, specimens were washed
in running water and stored in distilled water at 37ºC.
In group OB, the bleaching agent used was 35% hydrogen
peroxide for the in-office procedure. The gel was applied in
three applications, each one lasting 15 min. Two bleaching ses-
sions were performed, with a 1-week interval between them.
Afterthe bleaching treatment, the teeth surfaces were abun-
dantly washed with water. Between the sessions, the teeth
were stored in distilled water at 37ºC, changed daily.
In group HB, the bleaching agent used was 22% carbamide perox-
ide for at-home bleaching, for 15 consecutive days, being 2 hours
per day. The specimens were stored over cotton gauze soaked
with distilled water throughout the bleaching procedure. After the
bleaching treatment, the teeth surfaces were abundantly washed
with water, and stored in distilled water at 37ºC, changed daily.
Bracket debonding pliers were used to debond the accessories.
Removal of resin remnants was performed using a 12-blade
tungsten carbide bur on low-speed handpiece, at 20,000rpm
without water cooling.
One operator made the color evaluations, using the matrix to
standardize the spectrophotometer probe placement during
consecutive color evaluations.14,15,21,22 The color measurements
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were recorded at baseline and one month after bracket removal,
to give the teeth adequate time to rehydrate.15,23
The color was measured using color coordinates established
by the International Commission on Illumination (CIELab),
using the Easyshade device. The following values were eval-
uated: L*, a*, and b*, in which L* represent the value from
0 (black) to 100 (white), and a* and b* represent the shade,
where a* is the measurement along the red-green axis, and
b* is the measurement along the yellow-blue axis. The color
parameters were measured over a white background. The color
comparison before and after treatment was given by the dif-
ferences between the two shades (ΔEab), which was calculated
using the following formula:ΔEab = [(ΔL*)2 + (Δa*)2+ (Δb*)2]1/2,
where ΔL* = L*(final) - L*(initial); Δa* = a*(final) - a*(initial); and
Δb*= b*(final) - b*(initial). To evaluate the perception of tooth
whiteness, the CIELab-based whiteness index (WID= 0.511L*
−2.324a* −1.100b*) was also calculated. The whiteness index
change (ΔWID) was calculated according to the equation:
ΔWID =WIafter bleaching - WIbaseline.24,25 Three readings were done,
and the values were averaged for statistical purposes. The total
color alteration (ΔEab) was considered the primary outcome.
During the recording of the tooth color and performing the
statistical analyses, the researchers were blinded.
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STATISTICAL ANALYSES
The data were initially submitted to the Shapiro-Wilk test, and
the normality was demonstrated. The compatibility of the base-
line CIELab values between the areas compared (experimen-
talunder the bracket; and control around the bracket) was
individually evaluated by paired t-test. The paired t-test was
also applied to the intragroup comparisons between the exper-
imental (under the brackets) and the control (around the brack-
ets) areas, at 1 month after bleaching/whitening procedures.
Theintergroup comparisons were performed using the one-way
ANOVA and Tukey tests. The level of significance adopted was
5%, and statistical analyses were performed using the software
Statistica for Windows version 7.0 (Statsoft, Tulsa, Ok, USA).
RESULTS
The color coordinates evaluated (L*, a*, and b*) were similar
at baseline, for all groups, between under the bracket area
(experimental) and around the bracket area (control), demon-
strating that the areas compared were compatible regarding
color at baseline (Table 2).
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» Intragroup comparisons
Intragroup comparisons showed statistically significant dif-
ferences in color changes (ΔEab) for groups C, WThp and HB,
between under and around the bracket areas after bleaching
and whitening treatments (group C = 7.97 ± 2.35 x 2.86 ± 0.81,
Table 2: Descriptive statistics and intragroup comparisons of CIELab values under the
bracket (experimental) and around the bracket (control) areas at baseline.
SD = standard deviation. Intragroup comparison (paired t-test) (α  = 0.05). Groups: C = non-whitening toothpaste;
WTsi = hydrated silica whitening toothpaste; WThp = 2% hydrogen peroxide whitening toothpaste; OB = in-office
bleaching; and HB = at-home bleaching.
Initial
CIELab
UNDER THE BRACKET AREA
(experimental)
Mean ± SD
AROUND THE BRACKET AREA
(control)
Mean ± SD
p
Group C
L89.63 ± 2.04 90.82 ± 1.09 0.07
a1.40 ± 1.19 0.71 ± 0.74 0.09
b25.1 ± 3.65 22.4 ± 3.89 0.07
Group WTsi
L88.8 ± 3.32 90.0 ± 4.41 0.41
a -1.21 ± 2.13 -2.2 ± 1.81 0.19
b26.33 ± 6.02 22.68 ± 5.97 0.11
Group WThp
L90.17 ± 3.35 91.73 ± 1.92 0.14
a -2.61 ± 1.61 -2.24 ± 0.90 0.45
b22.08 ± 3.89 21.68 ± 3.90 0.78
Group OB
L88.25 ± 2.81 89.16 ± 3.36 0.44
a -1.66 ± 0.96 -1.42 ± 1.64 0.64
b 26.27 3.35 25.88 ± 4.53 0.79
Group HB
L89.92 ± 2.85 90.91 ± 2.19 0.31
a1.16 ± 2.00 0.73 ± 1.70 0.55
b26.39 ± 3.39 24.11 ± 3.06 0.07
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p < 0.01; group WThp = 4.69 ± 2.98 x 2.05 ± 1.41, p < 0.01;
groupHB = 7.41 ± 2.89 x 9.86 ± 3.32, p = 0.02). In groups C and
WThp, the under the bracket area demonstrated significantly
greater color change; while in group HB, the around the bracket
area underwent significantly greater color change (Table 3).
Lightness (ΔL*) was statistically greater for groups C and WThp at
under the bracket area (group C = 6.06 ± 2.49x1.08 ± 1.46, p < 0.01;
group WThp = 2.16 ± 3.17x-0.17 ± 1.13, p = 0.02) (Table 3).
Group C had, at under the bracket area, statistically significant
greater reduction in a* (group C = -2.53 ± 1.16 x -1.31 ± 0.72,
p < 0.01) and b* (group C = -3.75 ± 2.26x-0.29 ± 1.92, p < 0.01),
decreasing redness and yellowness, respectively. Group HB
showed a significant reduction in b* (group HB  -4.96 ± 2.48 x
-7.78 ± 3.19, p < 0.01) around the bracket area (Table 3).
Tooth whiteness (ΔWID) presented statistically significant dif-
ferences between the areas tested for groups C and WThp
(groupC=9.6 ± 4.3 x 0.2 ± 3.0, p < 0.01; groupWThp=1.8 ± 6.6
x-2.6 ± 3.6, p = 0.03), demonstrating greater alterations for the
under the bracket area (Table 3).
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Efficacy of products for bleaching and whitening under orthodontic brackets
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Table 3: Descriptive statistics, intragroup and intergroup comparisons of CIELab and WID values
under the bracket and around the bracket areas, one month after bleaching.
Intragroup comparison (paired t-test). Different superscript uppercase letters in columns indicate statistically
significant differences among the groups with ANOVA/Tukey test (α = 0.05). *Statistically significant at p < 0.05.
Groups: C = non-whitening toothpaste; WTsi = hydrated silica whitening toothpaste; WThp = 2% hydrogen
peroxide whitening toothpaste; OB=in-office bleaching; and HB=at-home bleaching.
UNDER THE
BRACKET AREA
(experimental)
Mean ± SD
AROUND THE
BRACKET AREA
(control)
Mean ± SD
p
ΔEab
C7.97 ± 2.35A2.86 ± 0.81A< 0.01*
WTsi 8.54 ± 3.63A6.17 ± 4.59B0.08
WThp 4.69 ± 2.98B2.05 ± 1.41A< 0.01*
OB 9.31 ± 4.32A10.72 ± 3.23C0.31
HB 7.41 ± 2.89A9.86 ± 3.32C0.02*
p< 0.01* < 0.01*
ΔL*
C6.06 ± 2.49A1.08 ± 1.46AB < 0.01*
WTsi 2.78 ± 4.98B3.32 ± 4.27AC 0.75
WThp 2.16 ± 3.17B-0.17 ± 1.13B0.02*
OB 5.50 ± 3.85A5.99 ± 2.47C0.65
HB 4.57 ± 2.43A5.30 ± 2.13C0.31
p0.01* < 0.01*
Δa*
C-2.53 ± 1.16A-1.31 ± 0.72AB < 0.01*
WTsi -1.65 ± 1.93AB -0.63 ± 1.54A0.12
WThp -0.68 ± 1.31B-0.18 ± 0.60A0.15
OB -2.14 ± 0.98A-2.46 ± 1.70B0.50
HB -2.26 ± 1.08A-1.89 ± 1.34B0.31
p< 0.01* < 0.01*
Δb*
C-3.75 ± 2.26AB -0.29 ± 1.92A< 0.01*
WTsi -5.60 ± 4.28A-3.53 ± 3.97B0.26
WThp -2.43 ± 2.99B-0.74 ± 2.06A0.06
OB -6.69 ± 3.27A-8.22 ± 2.75C0.16
HB -4.96 ± 2.48AB -7.78 ± 3.19C< 0.01*
p< 0.01* < 0.01*
ΔWID
C9.6 ± 4.3A0.2 ± 3.0A< 0.01*
WTsi 7.9 ± 10.9AB 3.5 ± 8.2A0.30
WThp 1.8 ± 6.6B-2.6 ± 3.6A0.03*
OB 11.6 ± 6.5A14.3 ± 6.8B0.33
HB 9.4 ± 5.0A12 ± 6.0B0.17
p< 0.01* < 0.01*
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» Intergroup comparisons
Intergroup comparisons demonstrated that the color change
(ΔEab) was similar for groups C, WTsi, OB, and HB at under the
bracket area (group C = 7.97 ± 2.35; group WTsi = 8.54 ± 3.63;
group OB = 9.31 ± 4.32; group HB = 7.41 ± 2.89) (Table 3).
Onlygroup WThp showed less color variation than the other
groups in this region (group WThp = 4.69 ± 2.98, p< 0.01). In the
around the bracket area, groups C and WThp showed similar
color changes (group C = 2.86 ± 0.81; group WThp = 2.05 ± 1.41),
group WTsi demonstrated different color alteration, in com-
parison with the other groups (group WTsi = 6.17 ± 4.59), and
groups OB and HB showed statistically greater color changes
(group OB = 10.72 ± 3.23; group HB = 9.86 ± 3.32).
At under the bracket area, greater lightness (ΔL*) was observed
for groups C, OB and HB (group C = 6.06 ± 2.49; group OB =
5.50 ± 3.85; group HB = 4.57 ± 2.43; p= 0.01), and at around the
bracket area for OB and HB (group OB = 5.99 ± 2.47; group HB =
5.30 ± 2.13; p< 0.01). The group WThp demonstrated the smallest
lightness change in the control area (group WThp = -0.17 ± 1.13).
The green-red axis (Δa*) showed greater reduction for groups
C, OB and HB at under the bracket area (group C = -2.53 ± 1.16;
group OB = -2.14 ± 0.98; group HB = -2.26 ± 1.08; p< 0.01); and
at around the bracket area for groups OB and HB (group OB =
-2.46 ± 1.70; group HB = -1.89 ± 1.34; p< 0.01).
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At under the bracket area, WTsi and OB demonstrated a sta-
tistically significant greater reduction in Δb* (group WTsi =
-5.60 ± 4.28; group OB = -6.69 ± 3.27; p < 0.01), decreasing
yellowness. At around the bracket area, OB and HB showed
a greater reduction of yellowness (group OB = -8.22 ± 2.75;
groupHB= -7.78 ± 3.19; p < 0.01) (Table 3).
Statistically significant greater tooth whiteness (ΔWID) was
observed for groups C, OB and HB at the under the bracket area
(group C= 9.6 ± 4.3; group OB= 11.6 ± 6.5; group HB=9.4 ± 5.0;
p < 0.01), and for groups OB and HB at the around the bracket
area (group OB= 14.3 ± 6.8; group HB= 12 ± 6.0; p < 0.01).
DISCUSSION
Although previous studies14-19 have evaluated the efficacy of differ-
ent dental bleaching agents under orthodontic brackets, no study
has evaluated the whitening toothpastes. Since many patients
wearing orthodontic appliances perceive changes in the shade of
their teeth, and whitening toothpaste is an easily accessible prod-
uct,12 its efficacy needed to be tested. The null hypothesis was
rejected since, considering the parameters ΔEab and ΔWID, simi-
lar results between under and around the bracket areas were
observed only for groups WTsi, OB, and HB.
The efficacy of whitening and bleaching procedures applied in
the present study was demonstrated, as observed in the results
obtained for the control area (around the bracket). Whiteningor
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bleaching was observed in groups WTsi, OB, and HB by the
evaluation method used, and color changes of approximately
6 to 10 ΔEab were detected.
Previous studies26,27 observed that hydrated silica whitening
toothpaste showed greater color changes than 2% hydrogen
peroxide whitening toothpaste, corroborating with the present
results. This finding suggested that the toothbrushing abra-
sion action was mainly responsible for the color changes.26 The
authors speculate that the low peroxide hydrogen concentra-
tion did not produce enough free radicals to oxidize dentin’s
organic component in the WThp group.28,29 The in-office and
at-home bleaching procedures showed statistically greater
color changes and similarity around the bracket area, corrobo-
rating with previous studies.18,19,21,22,25,30
The area under the bracket showed greater color alteration
and tooth whiteness, when compared with the area around the
bracket, for the non-whitening toothpaste, 2% hydrogen perox-
ide whitening toothpaste, and at-home bleaching procedure.
Previous studies31-34 also observed enamel color changes after
treatment with fixed orthodontic appliances, demonstrating an
increase in the tooth color’s lightness after bracket debonding.
The color change under the brackets is variable. Eliades et al.32
observed that tooth-color differences after debonding and clean-
ing procedures ranged from 5.27 ± 2.21 to 13.7 ± 4.7 ΔEab units.
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Factors such as acid etching, increased roughness, removal of
resin remnants and penetration of resin tags into the enamel
surface may have affected the light scattering of the under
the bracket area.32,34-37 Sardarian et al16 and Lunardi et al17 also
demonstrated statistically significant lower color change under
the bracket than around the bracket, after at-home bleaching
procedure. The peroxide concentration (22%) may also have
influenced this result.22,28,29
The differences in color change between the areas under and
around the brackets were 5.11 units for the non-whitening tooth-
paste group, 2.37 units for hydrated silica whitening toothpaste
group, 2.64 units for 2% hydrogen peroxide whitening toothpaste
group, 1.41 units for the in-office bleaching group, and 2.45 units
for at-home bleaching group. These results demonstrated that
the color change between the areas evaluated was clinically
significant only for the non-whitening toothpaste group, since,
for the other groups, the ΔEab values were below the standard
value for visual perceptibility and clinical detection of color
change (ΔEab 3.7 units).38 Therefore, the color variations proba-
bly would not be perceived by the human eye when hydrated
silica whitening toothpaste, in-office and at-home bleaching
are used in teeth with brackets.
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An average variation of 9.31 and 7.41 of color change (ΔEab) in
the area under the bracket for groups OB and HB was observed,
which agrees with previous studies:Montenegro-Arana etal15
showed a mean variation of 5 to 9 ΔEab; Jadad etal14 demon-
strated a mean variation of 8.5 ΔEab after bleaching treatment in
teeth with orthodontic brackets; and Sardarian et al16 showed
a mean variation of 8.51 to 10.84 ΔEab. The absence of previous
studies evaluating the effect of whitening toothpaste under
orthodontic brackets limits comparisons.
Despite the limitations of in vitro studies, recent studies11,12
have shown similar results after testing the color variation of
whitening toothpastes in vitro and in vivo. Tao et al12 highlighted
that the evaluation of tooth whitening products using in vitro
methods is important for the testing hypotheses and identify-
ing efficacious formulations. Moreover, since this study tested
toothpastes, the standardization of toothbrushing procedure
was important to eliminate bias.
Even though the color change was similar under and around the
bracket for the bleaching and whitening procedures in groups WTsi
and OB, and demonstrated clinical acceptability for HB, it is import-
ant to highlight that the use of these products in an abusive man-
ner may result in enamel alterations and tooth sensitivity.4,15,22,39
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Efficacy of products for bleaching and whitening under orthodontic brackets
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Bleaching is contraindicated in clinical conditions in which the
tooth presents exposed dentin or other enamel tissue changes
that presumably increase its permeability.14
According to the results obtained in the present study, the
in-office dental bleaching using 35% hydrogen peroxide,
at-home bleaching using 22% carbamide peroxide, and the
use of whitening toothpaste containing hydrated silica showed
effectiveness in the presence of metallic orthodontic brackets.
Therefore, in cases where orthodontic patients request dental
bleaching or whitening during orthodontic treatment, these
products may be indicated.
Further studies comparing enamel roughness and possible
physical and/or mechanical alterations in the orthodontic appli-
ances (e.g. wires, brackets and ligatures) must be encouraged.
CONCLUSIONS
Considering the results obtained for the color changes (ΔEab)
and the perception of tooth whiteness (WID), the dental color
changes were effective, in the presence of metallic orthodon-
tic brackets, for the use of whitening toothpaste containing
hydrated silica and in-office dental bleaching with 35% hydrogen
peroxide and at-home bleaching with 22% carbamide peroxide.
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AUTHORS’ CONTRIBUTIONS
Célia R. M. Pinzan-Vercelino (CRMPV)
Suellen N. Linares Lima (SNLL)
Fernando F. de J. V. Pereira (FFJVP)
Júlio de Araújo Gurgel (JAG)
Gisele Rodrigues da Silva (GRS)
Karina M. S. de Freitas (KMSF)
Conception or design of the study:
CRMPV, SNLL
Data acquisition, analysis or
interpretation:
CRMPV, SNLL, FFJVP, JAG, GRS, KMSF
Writing the article:
CRMPV, SNLL, FFJVP, JAG, GRS, KMSF
Critical revision of the article:
CRMPV, SNLL, FFJVP, JAG, GRS, KMSF
Final approval of the article:
CRMPV, SNLL, FFJVP, JAG, GRS, KMSF
Fundraising:
FFJVP
Overall responsibility:
CRMPV
The authors report no commercial, proprietary or financial interest in the products or
companies described in this article.
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Article
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Objectives: To compare the effects of different etching techniques, 12-, 24-bladed tungsten carbide burs, and polishing discs on tooth color changes during orthodontic treatment. Materials and methods: 59 individuals (mean age: 15.20 ± 1.59 years) were divided into four groups: 37% phosphoric acid and adhesive primer was used in Groups I and II whereas self-etch primer was used in Groups III and IV for enamel preparation. After orthodontic treatment, residual adhesives were cleaned with 12-bladed tungsten carbide burs in Groups I and III, while 24-bladed tungsten carbide burs were used in Groups II and IV. All teeth were polished with medium and fine Sof-Lex XT discs (3M ESPE, St Paul, Minnesota). Color measurements were taken from upper incisors and canines at pretreatment (T0), after cleaning with tungsten carbide burs (T1) and polishing with discs (T2). Wilcoxon test was used for evaluation of L*, a*, b* changes and Kruskal-Wallis for intergroup comparison of color changes. Results: L*, a*, b* values, except a* at Groups I, II, IV, and b* at Group III, changed significantly ( P < .05). Groups III and IV showed significantly different color alterations from T0 to T1 ( P < .05). After polishing, tooth color alterations were not significantly different among the groups. Conclusions: In self-etch bonding groups, a 12-bladed tungsten carbide bur caused less color change than the 24-bladed tungsten carbide bur. Orthodontic treatment resulted with visible and clinically unacceptable tooth color alterations regardless of the enamel preparation and clean-up techniques. Polishing reduced the effect of tungsten carbide burs, but did not affect the total influence of orthodontic treatment on the tooth color.
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Population-based studies estimating the prevalence of tooth bleaching desire or the percentage of individuals who had performed this treatment are rare. Thus, the aim of this study was to evaluate the desire to perform tooth bleaching and the prevalence of adult individuals who had performed the treatment and investigate the association of these outcomes. A subsample (n = 536) of the 1982 Pelotas birth cohort in southern Brazil was investigated at the ages 15, 24 and 31 by clinical examinations and interviews. The prevalence of bleaching at 31 years was 15.6% [95%CI 12.6–18.9] while 85.9% [95%CI 82.7–88.7] reported they desired the treatment. Multivariate Poisson regression analysis showed that individuals who have visited the dentist within the last year showed a treatment prevalence ratio (PR) 2.31 times [95%CI 1.40–3.83] higher compared with those who had the last dental visit more than a year before the interview. Similarly, individuals with smoking habits presented an elevated PR of 1.60 [95%CI 1.00–2.55], and the low-income trajectory group showed the largest PR of desire for tooth bleaching (1.17 [95%CI 1.07–1.28]). Moreover, individuals from the high-risk caries trajectory group presented a higher prevalence of desire for tooth bleaching than individuals from low caries trajectory group. Individuals who have declared being “dissatisfied” with their dental color presented a prevalence of desire for tooth bleaching 16% greater than “satisfied” ones. Thus, the present findings confirm that tooth bleaching has become a frequently desired dental treatment to improve dental aesthetics in the population and a considerable rate of adults has performed the treatment.
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Objective: To evaluate the color change and tooth whitening perception in 2 and 3 mm dental specimens simulating the orthodontic bracket for a 14-day period. Materials and methods: Forty bovine tooth fragments (8 × 7 mm) of 2 mm (G2, n = 20) and 3 mm (G3, n = 20) were divided into Control (C: without bracket simulation and whitening) and Experimental (E: with composite resin simulating orthodontic bracket cementation area). Analyses of color change (ΔE00 ) and perception of tooth whitening (WID ) were performed before (T0 ) and after (T1 ) the first bleaching session; before (T2 ) and after (T3 ) the second bleaching session; and after 7 days of the second bleaching session (T4 ). Results: After 14 days (T4), ΔE00 and WID showed similarity results, except for G2C and G3E. The thickness did not influence the ΔE00 and WID (G2C = G3C and G2E = G3E). The presence of orthodontic bracket did not interfere in the color change or tooth whitening perception after 14 days, except for comparison of G2C and G3E. Additionally, dentin thickness did not influence the color change. Clinical significance: Teeth with orthodontic brackets showed similar color change and whitening perception to teeth without orthodontic bracket, but it is not influenced by dentin thickness.
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Objective: This in-vitro study evaluated the color changes in enamel and dentin bleached in the presence of an orthodontic bracket, as well as the heterogeneity of the color and contribution of each tissue to the color change (CTCC). Materials and methods: Enamel-dentin specimens from extracted bovine teeth were bleached before or after bracket removal or maintained without any treatment (control). The colors of the dentin and enamel were measured individually and after recombining these substrates. The changes in the color (ΔE00 ) and whitening index (ΔWID) were estimated by the color difference between the bleached specimens and those of the control. The CTCC was also calculated by recombining the tissues from different treatments. Images of specimens obtained from a stereomicroscope were used to analyze the color homogeneity within each tissue. Results: The highest values of ΔE00 and ΔWID were observed in the specimens bleached in the absence of a bracket. Bleaching in the presence of a bracket resulted in enamel with a center that was whiter than the periphery. Dentin and enamel presented similar CTCC values. Conclusions: Tooth bleaching performed in the presence of a metallic bracket resulted in a reduced bleaching effect and increased color heterogeneity within both tissues. Clinical significance: Tooth bleaching before the orthodontic bracket removal reduces the bleaching effect in both dentin and enamel. Moreover, a heterogeneous color of enamel surface can be observed after tooth bleaching in the presence of a nickel-free metallic orthodontic bracket.
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Background: This study investigated the effect of two different methods of bleaching during orthodontic treatment on bracket bond strength. Materials and methods: A total of 45 extracted premolar teeth were selected in this experimental study and divided into three groups (office bleaching with 35% hydrogen peroxide, home bleaching with 22% carbamide peroxide, and control). The color of the teeth was assessed initially before the application of bleaching agents and Thermocycling. Orthodontic brackets were subsequently bonded on the treated surfaces. Bleaching procedures were then performed. A final color measurement was performed at two points on the buccal surface both underneath and adjacent to the bracket base. The initial and final color measurements and the bond strengths were compared between the groups using the analysis of variance. P < 0.05 was considered as statistically significant. Results: Bracket bond strength was significantly reduced in both bleaching groups compared with the control group (P < 0.01). The color difference before and after the bleaching procedures was significant in the office bleaching group (P < 0.01), while the control group did not demonstrate a statistical difference between initial and final color assessments (P > 0.05). Conclusion: Bleaching procedures performed during orthodontic treatment reduce bond strength. Enamel beneath the bracket base experiences a whitening effect though to a lesser degree compared with an uncovered surface.
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Objectives: To carry out a systematic review and meta-analysis of studies that investigated changes in perceived quality of life following vital tooth bleaching. Methods: Online searches (Medline, PubMed, the Cochrane database of systemic reviews and Google scholar), bibliographic, and manual searches were carried out. Two authors independently screened the 313 articles identified from the searches and two authors extracted data, including risk of bias using the Cochrane data collection form. Random effects meta-analysis was used to estimate the pooled standardized mean difference (with 95% CI) and the 95% prediction interval. Results: Only four studies met the inclusion criteria, two showing statistically significant improvement, one worsening, and one inconclusive. The pooled standardized estimate for change in quality of life after bleaching was 0.04 (95% CI -0.15, 0.24) with substantial heterogeneity (I-squared 82.1%). Within these studies, there was a pattern of improvement in aesthetic-related domains (e.g. smiling and psychological discomfort) and deterioration in function-related domains (e.g. hygiene and pain). Conclusions: Vital bleaching was not associated with improvements in overall Oral Health Related Quality of Life (OHRQoL) in these heterogeneous populations. Vital bleaching appeared to impact some domains of OHRQoL positively and some negatively, indicating the need for clinicians to treat patients receiving bleaching treatment so as to obtain the best improvement in aesthetics with minimal side effects. Clinicians should be aware of the potential impact caused by tooth sensitivity and offer proper instruction to prevent it or treatment to reduce its impact. Clinical significance: Bleaching treatment produces positive changes in young participants' OHRQoL in aesthetic areas such as smiling, laughing, and showing teeth without embarrassment. Tooth sensitivity, the main side-effect of vital bleaching treatment, can affect quality of life, and so oral health professionals should offer evidence-based advice to prevent and manage sensitivity.
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Introduction: The aim of this study was the long-term follow-up of enamel color changes observed in the middle third of buccal tooth surfaces after treatment with fixed orthodontic appliances. Methods: The study included 120 maxillary central and lateral incisors and canines of 20 subjects who had fixed orthodontic treatment. The Spectro Shade Micro device (MHT, Verona, Italy) was used to evaluate the color changes of the teeth. Measurements were made from the middle third of the buccal surfaces of the teeth after fixed orthodontic treatment and in month 3, month 6, and year 1 of the retention phase. The Commission Internationale de l'Echairage L* a* b* system that expresses the color coordinates in L*, a*, and b* symbols was used to determine the tooth color, and ΔE values between the time periods were calculated. Repeated measurement analysis of variance was used in evaluating the color changes. Results: The increases in ΔL values at 3 months, 6 months, and 1 year after treatment were statistically significant, whereas they were not statistically significant from months 3 to 6, month 3 to year 1, or month 6 to year 1. The decrease in Δa and the increase in Δb values were not statistically significant. ΔE values at all time periods were statistically significant within themselves, and the greatest change was observed 1 year after treatment. ΔE values were 1.52 to 3.57, and a visible but clinically acceptable color change occurred. Conclusions: In the first 3 months, there was a significant increase in the lightness of the tooth color.
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Recent studies suggested that bleaching agents may whiten teeth by oxidizing the fluorescent materials, which are the proteins located in the organic-inorganic interface. Therefore, we postulated that fluorescence of dentin came from dentin phosphoprotein (DPP) and that bleaching agents might bleach dentin by oxidizing DPP. Fifty-six specimens were randomly divided into 4 groups and exposed to distilled water, hydrogen peroxide (HP), ethylenediamine tetraacetic acid disodium salt (EDTA), and acetic acid for 24 h. After measuring the organic and inorganic components, fluorescence, and color characteristics of dentin before and after exposure, we found that when DPP was removed from dentin by EDTA, fluorescent intensity declined proportionally with the reduction in Raman relative intensity, and dentin was whitened considerably, with an ΔE value 6 times higher than that of the distilled water group. On the contrary, due to the incapability of acetic acid to dissolve DPP during decalcification, fluorescent intensity values and tooth color remained nearly unchanged after exposure to acetic acid. Dentin exposed to neutral HP showed no obvious morphologic and organic/inorganic component changes except for the destruction of DPP. Similarly, dramatically decreased fluorescent intensity and lightened color were found in the HP group. Moreover, DPP solution of the HP group exhibited decreased ultraviolet absorbance, especially between 250 and 300 nm, which arose from aromatic amino acids. The results indicated that DPP was responsible for the fluorescent properties of dentin and that HP might bleach dentin by the oxidization of aromatic amino acids in DPP. These findings are of great significance in promoting our further understanding of the mechanism of tooth bleaching and the fluorescent property of normal dentin.