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Clinical Performance of
Vital Bleaching Techniques
©Operative Dentistry, 2010,
35-1, 3-10
JK Bernardon • N Sartori • A Ballarin
J Perdigão • G Lopes • LN Baratieri
Clinical Relevance
Tooth bleaching results obtained with different techniques (home bleaching, in-office bleaching
with or without light source and a combination of in-office bleaching + home bleaching) were
similar after a two-week period. Dentists must inform their patients about the expected out-
comes of each procedure and provide an evidence-based choice.
SUMMARY
This study compared the clinical outcome of
bleaching techniques in vital teeth. After IRB
approval and informed consent, 90 subjects were
selected based on the shade of their anterior
teeth (A2 or darker, Vita Classic shade guide).
Subjects were assigned to three treatment
groups in a split-mouth study design: Group I:
HB (at-home bleaching with 10% carbamide per-
oxide for two weeks) vs OBL (in-office bleaching
with 35% hydrogen peroxide, two sessions, two-
week intervals, with light irradiation); Group II:
OB (in-office bleaching without light irradiation)
vs OBL; Group III: HB vs combination (one ses-
sion plus HB). Color change and color rebound
(∆∆E) were measured for a 16-week period. Color
measurements were carried out with both a spec-
trophotometer and a shade guide at baseline, 1, 2,
4, 8 and 16 weeks. Tooth sensitivity was evaluat-
ed using a VAS scale for 15 days. Both the
Student’s t-test and Tukey-Kramer test were used
to analyze the results (p<0.05). After one week,
one session of OBL followed by HB resulted in
lower color values, compared with the other
bleaching methods. Group III resulted in the
least shade values at one-week evaluation, when
compared with the other bleaching methods.
After two weeks, HB alone resulted in similar
*Jussara K Bernardon, DDS, MS, PhD, clinical professor,
Department of Operative Dentistry, Universidade Federal de
Santa Catarina, Florianópolis, SC, Brazil
Neimar Sartori, DDS, MS, graduate student, Department of
Operative Dentistry, Universidade Federal de Santa Catarina,
Florianópolis, SC, Brazil
Andressa Ballarin, DDS, research assistant, Department of
Operative Dentistry, Universidade Federal de Santa Catarina,
Florianópolis, SC, Brazil
Jorge Perdigão, DMD, MS, PhD, professor, Department of
Restorative Sciences, Division of Operative Dentistry,
University of Minnesota, Minneapolis, MN, USA
Guilherme Carpena Lopes, DDS, MS, PhD, clinical professor,
Department of Operative Dentistry, Universidade Federal de
Santa Catarina, Florianópolis, SC, Brazil
Luiz Narciso Baratieri, DDS, MS, PhD, professor, Department of
Operative Dentistry, Universidade Federal de Santa Catarina,
Florianópolis, SC, Brazil
*Reprint request: Amaro Antonio Vieria 2489 apto 403,
Florianópolis, 88034-102, Brazil; e-mail: jussara_bernardon@
yahoo.com.br
DOI: 10.2341/09-008CR
Clinical Research
color changes as OB, OBL and OBL+HB. The use
of light irradiation did not improve bleaching
efficacy (OB = OBL). OBL and OB resulted in
higher sensitivity rates than HB.
INTRODUCTION
Currently, there are a number of tooth bleaching tech-
niques available to clinicians. Home bleaching and in-
office bleaching are widely used in dental practice.1-2 One
of the advantages of home bleaching has been reported
to be its efficacy, which is readily noticed favorably by
patients.3-4 However, home bleaching requires a longer
treatment time than in-office bleaching, which may
contribute to its higher incidence of tooth sensitivity
during treatment.3In spite of it being considered less
effective, in-office bleaching may achieve noticeable
results in one or two sessions.4-5 A study evaluating
patients’ satisfaction found that a single in-office
bleaching session is not sufficient to achieve satisfacto-
ry results.5
Within these two main categories of bleaching tech-
niques, there are other variables, including type of
bleaching agent, concentration and application time.2,6-7
Carbamide peroxide (CP), in concentrations between
10% and 22%, and hydrogen peroxide (HP), in concen-
trations from 4% to 8%, are indicated for home bleach-
ing for prolonged periods of time.2,6,8 In-office bleaching
is performed using high-concentration HP (25% to
50%), which can be light-activated to accelerate the
bleaching process.9-10
Manufacturers’ recommendations for using light irra-
diation with in-office bleaching have become more fre-
quent in the last few years. However, use of a light
source as an adjunct to in-office bleaching has been
questioned in the literature.1,4,11-13 In fact, clinical studies
show that light does not influence the degree of bleach-
ing, while it may potentiate tooth sensitivity.11-14 A
short-term color rebound has also been described
for in-office bleached teeth.15-16
The combination of in-office and at-home bleach-
ing has been suggested to potentiate the bleaching
effect and improve color stability.7,17 Many dentists
perform in-office bleaching complemented with at-
home bleaching. In-office bleaching with 35% HP
is performed during the first session to provide an
initial “jump-start” bleaching effect. Then, the
patient is given a home-bleaching agent, usually
CP, in a custom-made tray, which is to be used
until the desired shade is obtained.17
Since clinical studies comparing these techniques
are not abundant, it is necessary to evaluate the
effects of the most commonly used bleaching tech-
niques. Therefore, the current study compared the
clinical performance of three bleaching strategies
in terms of their effectiveness, durability of the
bleaching effect and tooth sensitivity. The null hypothe-
ses tested in the current study were: 1) there is no dif-
ference between home bleaching and in-office bleaching
with light irradiation; 2) there is no difference between
in-office bleaching with light irradiation and in-office
bleaching without light irradiation; 3) there is no dif-
ference between home bleaching and the combination of
one session of in-office bleaching with light irradiation
and home bleaching.
METHODS AND MATERIALS
After approval by the Ethics Committee and Informed
Consent, 90 subjects were selected according to the
inclusion and exclusion criteria cited in Table 1. For a
direct comparison of the different bleaching tech-
niques, a split-mouth design was selected, in which the
same patient was randomly submitted to different
treatments in the left and right sides of the maxillary
arch. The side was determined by flipping a coin. The
selected patients were randomly divided into three
groups (n=30): Group I–at-home bleaching with 10%
CP for two weeks (HB) versus in-office bleaching with
35% HP with light irradiation (OBL); Group II–OBL
versus in-office bleaching without light irradiation
(OB); Group III–HB versus a combination of OBL (one
session) and HB.
After tooth prophylaxis and registration of the initial
shade of the six maxillary anterior teeth using a shade
guide (Vita Classic, Vita Zahnfabrik, Bad Säckingen,
Germany) and a spectrophotometer (Vita Easyshade,
Vident, Brea, CA, USA), the bleaching procedures were
carried out (Figures 1-3).
Home bleaching was accomplished with 10% CP
(Whiteness Perfect, FGM, Joinville, SC, Brazil). In its
formulation, this bleaching agent contains 3% potassi-
um nitrate and 0.2% sodium fluoride. The bleaching
4
Operative Dentistry
Inclusion Criteria
•Absence of restorations or presenting restorations with less than ¼ of the
labial surface in all anterior maxillary and mandibular teeth;
•Absence of tooth sensitivity (stimulated sensitivity using air
syringe);
•Patients older than 18 years;
•A2 shaded (or darker) teeth (Vita shade guide arranged by value).
Exclusion Criteria
•Pregnant or breastfeeding women;
•Patient with periodontal disease or to be treated for periodontal dis-
ease; patient with or to be treated for periodonal disease;
•Previous bleaching treatment;
•Tetracycline discoloration;
•Smoker;
•Tooth sensitivity;
•History of treatment of tooth sensitivity;
•Patient able to attend the follow-up appointments.
Table 1:
Inclusion and Exclusion Criteria
5
Bernardon & Others: Clinical Performance of Vital Bleaching Techniques
gel was inserted in the internal facial aspect of the
tray, which was used for two weeks in an eight-hour
daily regimen. The tray did not have reservoirs and
was trimmed 2 mm beyond the gingival margin. Facial
perforations were made in the region of the tray that
corresponded to the teeth that would not be treated in
order to prevent the gel from being applied on those
teeth.
For in-office bleaching, 35% HP (Whiteness HPmaxx,
FGM) was used (two sessions, three applications for
each session, 15 minutes per application, 15-day inter-
vals) according to the manufacturer’s instructions. A 2-
mm thick gingival barrier was applied on the soft tis-
sues from canine to canine prior to application of the
bleaching gel using a light-curing resin (Top Dam,
FGM). The right and left quadrants were separated by
a metallic matrix band inserted in the midline to con-
fine placement of the corresponding bleaching gel
(Figure 1). An LED/laser unit was used for four min-
utes (Whitening Lase, DMC, São Carlos, SP, Brazil) to
irradiate the HP bleaching gel.
The bleaching outcome was evaluated qualitatively
using a visual method with the aid of a Vita Classical
shade guide and quantitatively using a Vita
Easyshade spectrophotometer after 1, 2, 4, 8 and 16
weeks from the start of the treatment. Two blinded,
previously calibrated examiners participated in the
visual evaluation. They selected the tooth color using
the Vita Classic shade guide arranged in decreasing
order of value: B1, A1, B2, D2, A2, C1, C2, D4, A3, D3,
B3, A3.5, B4, C3, A4 and C4.
To standardize the lighting conditions during shade
determination, a 500° Kelvin hand-held lamp was
used (Color-I-dent, Waldmann, Germany) as recom-
mended by the manufacturer. In case of disagreement,
the differences were discussed between the evaluators
until a final consensus was obtained. The selected tab
in the shade guide was converted to previously estab-
lished numeric values (Table 2),4,12 ranging from 1 (B1)
to 16 (C4). The smaller the numeric value, the lighter
the tooth.
For the spectrophotometric evaluation, the device
used was the Vita Easyshade (Vident, Brea, CA, USA)
to obtain L*, a* and b* values of the CIELab system for
Figure 1
. Illustration of the bleaching techniques used in Group I: Home
bleaching (Figure 1A) vs In-office bleaching with light irradiation (Figure
1B).
Figure 2
. Illustration of bleaching techniques used in Group II: In-office
bleaching without light irradiation (Figure 2A) vs in-office bleaching with
light irradiation. Notice that the teeth of the hemi-arches that were not irra-
diated with light were protected with silicone during the light irradiation
(Figure 2B).
Figure 3
. Illustration of the bleaching techniques used in Group III: a com-
bination of one session of in-office bleaching with light irradiation (Figure
3A) vs home bleaching (Figure 3B).
each tooth. L* indicates the brightness, and a* and b*
represent hue. The a* axis represents saturation in the
red-green axis and b* is the saturation in the blue-yel-
low axis. For each period, color was compared before
and after the bleaching procedure using the color dif-
ference or ∆E, according to the formula:2,18 ∆E = [(∆L)2+
(∆a)2+ (∆b)2]1/2, with ∆L = final L–initial L; ∆a = final
a–initial a, and ∆b = final b–initial b. To standardize
the area of the tooth for shade taking, a silicon index
extending from canine to canine was fabricated with a
VPS impression material (Express Putty, 3M ESPE, St
Paul, MN, USA). A perforation compatible with the
size of the spectrophotometer tip was made in the mid-
dle-third of the facial surface (6 mm diameter) with a
scalpel blade (Figure 4).12 Standardized photographs
(Figure 5) were
taken at each eval-
uation period to
allow for observa-
tion of the results
obtained by the
different tech-
niques up to the
16-week period.
Tooth sensitivity for each hemi-arch was evaluated
on a daily basis by the patient for two weeks (period of
bleaching) and recorded on a clinical form. Pain inten-
sity was classified in a 0-10 scale ranging from “with-
out any discomfort” to “extremely unpleasant or
uncomfortable” using the 10-cm VAS scale as the ref-
erence and recorded on the form.19
Statistical analyses were carried out with ANOVA for
repeated measures using statistical package software
(Statistical Analysis System, SAS Institute, Cary, NC,
USA). The Student’s t-test was used for comparison
between the bleaching techniques and the Tukey-
Kramer test for comparison of bleaching techniques
with time (p≤0.05).
RESULTS
The results obtained with visual and spectrophotomet-
ric analyses are displayed in Tables 3 and 4, respective-
ly. Means and standard deviations for each group are
presented for comparison of the bleaching techniques
and evaluation periods. All the techniques evaluated
were effective for tooth bleaching, resulting in a statis-
tically similar degree of bleaching at two weeks, and
color stability was acceptable over a 16-week period.
The degree of bleaching obtained with the in-office
bleaching technique was statistically higher than that
obtained with the home-bleaching technique only at the
one-week evaluation period. The degree of bleaching
was similar at the second week for both techniques.
Evaluation of the results for tooth sensitivity was not
subjected to statistical analysis. The comparison of pain
intensity for the different bleaching techniques was
extrapolated from the analysis of Figure 6.
DISCUSSION
This in vitro study applied a
split-mouth design in order to
compare different bleaching tech-
niques. This design allows for
simultaneously comparing two
bleaching techniques in the same
patient, reducing the influence of
tooth-related and patient-habit
variables commonly observed in
the bleaching treatment.7,20
6
Operative Dentistry
Tab Value Tab Value Tab Value Tab Value
B1 1 A2 5 A3 9 B4 13
A1 2 C1 6 D3 10 C3 14
B2 3 C2 7 B3 11 A4 15
D2 4 D4 8 A3,5 12 C4 16
Table 2:
Representation of Conversion of Vita Classical Shade Guide Tabs to Numeric Values
Figure 4
. Tip of the spectrophotometer placed in the labial perforation of
the silicone matrix. The matrix was used for individual evaluation of the six
maxillary anterior teeth.
Figure 5
. Color change observed in a patient in Group III (right side: home bleaching, left side: 1 session
of in-office bleaching + home bleaching) at different evaluation periods.
7
Bernardon & Others: Clinical Performance of Vital Bleaching Techniques
The color
change obtained
by the different
bleaching tech-
niques was eval-
uated with a sub-
jective method
(visual examina-
tion, with the aid
of the shade
guide) and an
objective method
(spectrophotome-
ter). The similar
outcome regard-
ing color change
observed with
both evaluation
methods corrobo-
rates the reliabil-
ity and precision
of the results
obtained.4,21-23
The mean ∆E
values obtained
at the end of the
bleaching treatment for both home bleaching (∆E≈9)
and in-office bleaching (∆E≈8.7) were comparable to the
mean ∆E values reported in the literature for these
techniques.4,24 It has been suggested that a variation ∆E
from 3.3 to 3.7 produces clinically perceptible color
changes.25
Considering the statistical analysis, it was observed
that all evaluated techniques were effective for bleach-
ing vital teeth in general, showing the effectiveness of
HP as a bleaching agent, regardless of the concentra-
tion and application regimen.4,12,26
Different from home bleaching, which produced sig-
nificantly increased bleaching at one week, a far
greater bleaching effect (higher ∆E) was observed only
after the two-week evaluation in teeth bleached exclu-
sively with the in-office technique. This was expected,
because the second bleaching session was performed on
the day of the two-week evaluation and only after color
registration. Therefore, the final color obtained by the
in-office technique was taken only at the four-week
evaluation. It should be emphasized that this difference
in the degree of bleaching between the in-office tech-
nique and at-home was clinically noticeable according
to the results of the visual evaluation (Table 3). A pos-
sible explanation is that the teeth were dehydrated to
some extent by the 500°K lamp and the teeth appeared
lighter. However, all the teeth were subjected to the
same conditions.
Period (weeks)
Groups Treatment 12 4 8 16
G I HB 3.95 ± 2.46 aA 3.00 ± 2.14 aB 2.64 ± 1.86 aB 2.69 ± 1.91 aB 3.10 ± 1.87 aB
OBL 3.58 ± 2.15 aA 3.26 ± 2.07 aA 2.64 ± 1.76 aB 2.63 ± 1.70 aB 2.88 ± 1.57 aB
G II OB 3.06 ± 1.69 aA 3.30 ± 1.98 aA 2.26 ± 1.30 aB 2.35 ± 1.38 aB 2.59 ± 1.45 aAB
OBL 3.13 ± 1.84 aA 3.06 ± 1.79 aA 2.26 ± 1.37 aB 2.32 ± 1.38 aB 2.45 ± 1.34 aAB
HB 2.72 ± 1.80 aA 2.17 ± 1.33 aAB 2.00 ± 1.18 aB 2.42 ± 1.45 aAB 1.99 ± 1.34 aB
G III HB + 1 2.20 ± 1.49 bA 1.79 ± 1.38 bA 1.71 ± 1.16aA 2.18 ± 1.45 aA 1.75 ± 1.08 aA
session OBL
Means with identical lowercase letters in the same columns for each group are not statistically different (Student’s
t
-test,
p
>0.05).
Means with identical capital letters for each group within the same rows are not statistically different (Tukey-Kramer test,
p
>0.05).
Table 3:
Means and Standard Deviations of Subjective Evaluation (shade guide)
Period (weeks)
Groups Treatment 12 4 8 16
G I HB 6.33 ± 2.94 aA 8.40 ± 3.59 aB 8.91 ± 3.42 aB 9.08 ± 3.39 aB 8.82 ± 3.76 aB
OBL 7.53 ± 3.63 bA 7.41 ± 3.33 bA 9.18 ± 3.76 aB 9.39 ± 3.72 aB 8.98 ± 3.84 aB
G II OB 6.65 ± 2.73 aA 6.17 ± 2.62 aA 8.41 ± 3.14 aB 7.96 ± 3.26 aB 8.03 ± 3.08 aB
OBL 6.86 ± 2.80 aA 6.64 ± 3.08 aA 8.76 ± 3.40 aB 8.61 ± 3.48 aB 8.37 ± 3.08 aB
HB 7.74 ± 3.18 bA 9.30 ± 3.56 aB 10.00 ± 3.62 aB 9.50 ± 3.46 aB 9.70 ± 3.37 aB
G III HB + 1 8.87 ± 3.51 aA 10.07 ± 3.52 aB 10.82 ± 3.62 aB 10.09 ± 3.54 aB 10.32 ± 3.62 aB
session OBL
Means with identical lowercase letters in the same columns for each group are not statistically different (Student’s
t
-test,
p
>0.05).
Means with identical capital letters for each group within the same rows are not statistically different (Tukey-Kramer test,
p
>0.05).
Table 4:
Means and Standard Deviation of Objective Evaluation (spectrophotometric analyses: ∆E)
Figure 6
. Representation of tooth sensitivity reported during the bleach-
ing treatment period.
Group I: Comparison of Home Bleaching vs In-
office Bleaching with Light Irradiation
In order to obtain lighter teeth in less time, in-office
bleaching using a high concentration HP associated or
not associated with a light source has been recom-
mended.9-10,27
In the current study, the degree of bleaching obtained
via the in-office technique with light irradiation (35%
HP, six applications for 15 minutes each) was higher
than that obtained by the home bleaching technique
(10% CP/8 hours/14 days) only after the first week. In
all other evaluation periods, the bleaching obtained by
the home bleaching technique was similar to that
obtained by the in-office technique, regardless of the
use of a light source. This result corroborates the in
vitro findings of Sulieman and others,9who found that
a high-concentration gel produced similar bleaching to
a low-concentration gel, and it reaches the final results
more rapidly. On the other hand, these findings were
different from Auschill and others1and Zekonis and
others,4where both obtained significantly lighter teeth
with the home bleaching technique (∆E≈10.3) compared
with the in-office technique without light irradiation
(∆E≈4.05).
None of the techniques evaluated in the current study
resulted in color rebound at the 16-week evaluation.
The bleaching obtained with the home bleaching tech-
nique (∆E≈9) and the in-office technique (∆E≈8.7) did
not relapse with time. Regarding the home bleaching
technique, this behavior corroborates the findings of
Meireles (2008), who observed maintenance of the
bleaching effect using 10% and 16% CP for up to six
months. Conversely, Zekonis and others4reported color
rebound for teeth bleached with 10% CP after 12 weeks
(∆E≈6.39). For the in-office technique, the findings of
the current study were opposite the other studies,
which found short-term color rebound.5,12,16,20,28
Group II: Comparison of In-office Bleaching With
and Without Light Irradiation
Because there have been claims that use of a light
source accelerates the bleaching process,9,29 the current
study evaluated the influence of light irradiation on the
effectiveness and durability of an in-office bleaching
technique.
Similar results were observed when teeth bleached
using the in-office technique and light irradiation were
compared to teeth bleached without light irradiation,
either for spectrophotometric or shade guide evalua-
tion. ∆E values obtained in the hemi-arch bleached with
the in-office technique with light irradiation (∆E =8.41)
were not statistically different from those obtained in
the hemi-arch, where the gel was not irradiated with
light (∆E=8.76), in spite of a subtle decrease in ∆E. This
corroborates the findings of other research projects.4,11,13-14
Considering that no color rebound was observed for up
to 16 weeks in teeth bleached using the in-office tech-
nique, the use of a light source should be considered
optional for this technique when using high-concentra-
tion HP. These findings contradict other studies that
have reported color rebound with time for in-office
bleaching associated12,29 or not4-5 associated with light
irradiation.
Group III: Comparison of Home Bleaching vs a
Combination of In-office and Home Bleaching
Techniques
Another treatment option is a combination of two
bleaching techniques. According to the literature, this
combination may accelerate the bleaching process and
promote color stability with time.2,13,15
In the current study, the technique associating one
session of in-office bleaching to the home bleaching
technique obtained higher ∆E values and lower values
after conversion from the visual evaluation at the one-
week period. Clinically, this means lighter teeth in less
time. Therefore, the mixed technique accelerated the
bleaching process. However, after the second week, ∆E
obtained for the hemi-arches bleached with this combi-
nation were not statistically different from ∆E obtained
from teeth bleached using custom trays with 10% CP.
This suggests that both techniques were similarly effec-
tive after the second week.
Both techniques in this group presented color stabili-
ty for up to 16 weeks. It has been shown that one ses-
sion of in-office bleaching associated with home bleach-
ing does not influence the maintenance of color with
time.
Tooth Sensitivity
Tooth sensitivity is a side effect commonly reported in
the literature after vital tooth bleaching.1,2,12,30 In vitro
studies have shown that the peroxide diffuses into
enamel and dentin and reaches the pulp. The peroxide
concentration within the tissues is related to the con-
centration of the bleaching agent.30-31 Notwithstanding,
the mechanism responsible for bleaching-related tooth
sensitivity has not been established; in the current
study, the hemi-arches bleached with the in-office tech-
nique (35% HP) resulted in a higher degree of tooth sen-
sitivity when compared to the hemi-arches treated with
the home-bleaching technique. This might be associat-
ed with the high concentration of bleaching agent used
in the in-office bleaching technique. The reported sensi-
tivity was moderate and was more severe on the day of
the gel application, and it virtually disappeared after
four days for most patients, similar to a study by
Marson and others. Tooth sensitivity has been associat-
ed with heating produced by light irradiation of the
bleaching agent.11-12,22,29 In the current study, the use of a
light source did not influence the intensity of sensitivi-
ty reported by patients, and this was similar for the
Operative Dentistry
8
Bernardon & Others: Clinical Performance of Vital Bleaching Techniques
hemi-arches bleached with and without light irradia-
tion.
Regarding the home-bleaching technique, the value
ascribed to pain intensity was as low as 0.5 (0-5 scale),
that is, sensitivity was virtually non-existent through-
out the evaluation period. It should be emphasized
that, according to the manufacturer, the bleaching
agent used contains a combination of potassium nitrate
and sodium fluoride as desensitizing agents, which
may reduce tooth sensitivity.32 This finding did not cor-
roborate with the findings of Zekonis and others, who
found higher sensitivity for home bleaching (10% CP)
when compared to in-office bleaching (35% HP).4The
reason could be the absence of a desensitizing agent in
the formulation of the bleaching agent used in their
research.
CONCLUSIONS
Within the limitations of the current study, it can be
concluded that.
• The degree of bleaching obtained with the
home-bleaching technique was similar to that
obtained with the in-office technique, regard-
less of light irradiation or the combination of
home/in-office techniques.
• The use of a light source for in-office bleaching
did not influence the rate of bleaching, the
intensity of tooth sensitivity and the durability
of the bleaching effect; therefore, light irradia-
tion is not recommended.
• The combination of in-office and home-bleach-
ing techniques increased the rate of bleaching
only in the first week. However, the same com-
bination did not influence the results after the
first week.
• Higher sensitivity was observed with the in-
office technique immediately after treatment,
regardless of light irradiation.
(Received 14 January 2009)
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