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Clinical Performance of Vital Bleaching Techniques

Authors:

Abstract

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 outcomes of each procedure and provide an evidence-based choice.
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 (p0.05).
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 (E9)
and in-office bleaching (E8.7) 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 (E10.3) compared
with the in-office technique without light irradiation
(E4.05).
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 (E9) and the in-office technique (E8.7) 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
(E6.39). 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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... This procedure involves the application of a chemical agent that oxidizes the organic pigmentation, eliminating stains by chromogenic degradation [9,10]. Larger chromogenic pigments break down into smaller, less intensive pigments, thus lightening the color of the teeth [11]. ...
... Due to its low molecular weight, HP diffuses easily from the pulp chamber and can penetrate the dentine releasing oxygen which breaks the double bonds of organic and inorganic compounds within the dentinal tubules [11,17,18,19]. The deeper the penetration, the more pigment that causes the color alteration of dental tissues can be reversed by the oxidation reaction [20]. ...
Article
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Internal bleaching is a conservative, non-invasive, and simple treatment that is frequently performed in daily clinical practice. The present in vitro study analyzes the oxygen expansion of different bleaching agents resulting from the oxidation reaction when interacting with enamel and dentin. Enamel and dentin were crushed separately until obtaining a fine powder with particles of an approximate size between 0.06 and 0.2 mm. Each enamel and dentin sample were mixed with 37% carbamide peroxide (CP 37%), 30% hydrogen peroxide (HP 30%), sodium perborate (SP) combined with HP 30% (HP 30% + SP) and SP with distilled water (SP). A total of 280 1 mm diameter glass tubes were used with 70 for each bleaching agent (30 for powdered enamel evaluation, 30 for powdered dentin evaluation, and 10 controls). The bleaching agents were placed in the prepared tubes immediately after mixing the components. As expansion occurred, the oil inside the tube was displaced, through which the resulting expansion was evaluated and measured for 10 days. A significant expansion was observed that varied in magnitude according to the bleaching agent and the tooth structure used. Student’s t test and Welch’s ANOVA were used to analyze the data obtained. The highest mean expansion of both enamel and dentin was observed with 30% HP (66.6 mm for enamel, 94.5 mm for dentin) followed by HP 30% + SP (48.6 mm for enamel, 52.7 mm for dentin), CP 37% (38.4 mm for enamel, 52.6 mm for dentin) and finally SP with water (12.7 mm for enamel, 4.4 mm for dentin). It was observed that the expansion in the SP group with enamel was significantly lower than in the rest of the groups, while that registered for HP 30% was significantly higher. (p
... To standardize the area of the tooth for color analysis, a silicone matrix was performed with Zetalus heavy condensation silicone (Zhermack, Badia Polesine, RO, Italy). After molding, a perforation compatible with the size of the spectrophotometer tip was made in the middle-third of the buccal face of the incisor's crowns with the aid of a 6 mm diameter circular scalpel (Harte Instrumentos Cirúrgicos, Ribeirão Preto, SP, Brazil), leaving the enamel exposed area compatible with the diameter of the device tip [22,37]. ...
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Full-text available
Aim : To evaluate in vitro the whiteness index (WID) and the whiteness index variation (ΔWID), as well as the color stability of stained endodontically treated teeth after bleaching with violet LED (VL) and with hydrogen peroxide 35% (HP) associated or not to VL. Methods : Twenty-four lower incisors were selected. The color was measured using a spectrophotometer at the following times: baseline, after staining, bleaching, and thermocycling, to determine the whiteness index and variation (WID and ΔWID). For the staining process, the teeth were immersed in human blood and centrifuged. After biomechanical preparation, the specimens were distributed into three groups (n=8): control group (HP); violet LED (VL); and HP 35% + VL (HP+VL), and one session was performed for both bleaching procedures every week for three weeks, followed by thermocycling, where 10000 cycles were performed. After color analysis, the data obtained were submitted to statistical analysis (RM ANOVA, P<0,05). Results : The staining of the teeth reduced the WID values for all experimental groups compared to baseline, and the bleaching protocols increased WID values, with the lowest WID values for group VL. There was no statistically significant difference after thermocycling for all groups compared to bleaching. Staining and thermocycling reduced the ΔWID values, and no difference was found between treatments at these assessment times. Bleaching increased the ΔWID values, with less pronounced changes in the VL group. Conclusion : VL used alone has a lower bleaching effect compared to the bleaching treatment with HP, whether or not associated with VL, and the color stability was observed for all groups.
... Among the techniques used to bleach vital teeth, the most common is at-home bleaching, which consists of the application of bleaching agents in low concentrations in individual trays used by the patient outside the office environment [4][5][6]. This technique reduces the clinical time in contact with the patient, which reduces costs [5]. ...
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Objectives This split-mouth randomized, single-blind clinical trial evaluated the gingival irritation (GI) of at-home bleaching with individual trays of different cutouts, as well as the tooth sensitivity (TS) and color change. Materials and methods One hundred and twenty patients were randomized as to which side would receive the type of bleaching tray cutout: scalloped (in the gingival margin) and nonscalloped (extended from the gingival margin). The at-home bleaching was performed for 30 min with 10% hydrogen peroxide (HP) for 2 weeks. The absolute risk and intensity of GI and TS were assessed with a visual analog scale. Color change was assessed using a digital spectrophotometer and a color guide (α = 0.05). Results The proportion of patients who experienced GI was 57.5% (odds ratio 95% CI = 1.1 [0.7 to 1.8]), with no significant difference between groups (p = 0.66). The proportion of patients who experienced TS was 64.1% (odds ratio 95% CI = 1.0 [0.6 to 1.6]), with no significant difference between groups (p = 1.0). There is equivalence of scalloped and noscalloped groups for GI intensity (p < 0.01). Significant whitening was detected for both groups. Although some differences were observed between groups (CIELab and CIEDE00; p < 0.02), these were below of the considered clinically noticeable. Conclusions The different cutouts of trays proved to be equivalent when regarding gengival irritation and tooth sensitivity when 10% HP for at-home bleaching was used. Significant color change was observed in both groups. However, significant differences detected between groups are not considered clinically noticeable. Trial registration Brazilian Clinical Trials Registry (RBR-2s34685). Clinical relevance Scalloped or not, the individual trays for at-home bleaching could be considered a clinician’s decision.
... However, the at-home alternative uses a lower concentration (6-7.5%) of HP or CP gel with a longer gel-contact period [2,8,9]. Additionally, many studies have shown that office and home bleaching can achieve similar results since both can improve the appearance of teeth and provide satisfactory results for patients [10][11][12]. Moreover, it was shown that a low concentration bleaching agent used for longer periods is equally as efficacious with regard to bleaching, as a high concentration agent [13]. ...
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Objectives The current tooth bleaching materials are associated with adverse effect. Photodynamic method based on a novel photosensitizer alone, without combining with peroxides, is evaluated for tooth bleaching application.Materials and methodsTeeth samples were randomly divided into 3 groups with different treatment schemes, including negative control group (group A, physiological saline), experimental group (group B, ZnPc(Lys)5), and the positive control group (group C, hydrogen peroxide). Tooth color, surface microhardness, and roughness were determined at baseline, right after the first and second phase of bleaching, as well as 1 week and 1 month post-bleaching. Four samples in each group was randomly selected to evaluate the changes in surface morphology using the scanning electron microscope.ResultsThe color change values (ΔE) in group B (7.10 ± 1.03) and C (12.22 ± 2.35) were significantly higher than that in group A (0.93 ± 0.30, P < 0.05). Additionally, surface microhardness and roughness were significantly affected in group C, but not in the group A and B. Furthermore, the scanning electron microscope images showed no adverse effect of enamel in the group A and B while the group C demonstrated corrosive changes.Conclusions ZnPc(Lys)5 had a satisfactory bleaching effect and is promising to be a new type of tooth bleaching agent.Clinical relevanceThe current tooth bleaching materials give a satisfactory clinical outcome and long-term stability, but associated with some adverse reactions. Photosenstizer ZnPc(Lys)5 eliminated the main side effects observed in hydrogen peroxide-based agents on the enamel, and also had a satisfactory bleaching effect and provide a novel selective bleaching scheme for clinical use.
Article
Abstract This study reviews the knowledge on the use of conventional dental whitening and the use of enzymes as a new approach in bleaching. A review of the literature was based on academic articles and on patents related to the use of enzymes in dental bleaching. Tooth whitening techniques used nowadays are well reported in the literature, and its mechanism of action consists of an oxidoreduction reaction with the release of free radicals. The great instability of radicals, when in contact with the tissues, promotes oxidation and reduction in the size of the pigment chains incorporated into them. These pigments are eventually broken down into smaller and smaller molecular chains and end up being diffused from the dental structure. In turn, the use of enzymes aimed at tooth whitening can be a less harmful alternative to the tooth because their specificity regarding the substrate makes them of great interest to perform specific reactions, reducing collateral effects. The use of proteolytic enzymes and oxidoreductases paired with the application of peroxides, can be a promising alternative for obtaining even better results in the dental bleaching process.
Article
Objective: Few studies evaluated low concentrations of hydrogen peroxide protocols. The aim of this paper was evaluated two application protocols using 4% hydrogen peroxide in at-home bleaching. Materials and methods: Eighty-six patients with upper canines' shade A2 or darker were randomly allocated under two experimental conditions: two daily applications of 1 h each or a 2-h single application. Color change was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer weekly and 1 month after the bleaching procedure through one-way ANOVA. The risk and intensity of tooth sensitivity (TS) was assessed through visual and numeric rating scale and measured by Fisher's exact test, Mann-Whitney test and one-way ANOVA respectively. Results: After 3 weeks, the mean difference for the ΔSGU Vita Classical (1.0; 95% CI -0.1 to 2.0), ΔEab (0.7; 95% CI -1.4 to 2.8), ΔE00 (0.1; 95% CI -1.4 to 1.6) and Wi (1.8; 95% CI -1.9 to 5.5) presented no difference (p > 0.08). The relative risk for TS was 0.91 (0.72 to 1.14) without significant difference neither in the risk (p = 0.6) nor in the TS intensity for both pain scales (p > 0.65). Conclusions: The application protocols evaluated (two daily applications of 1 h each or a 2-h single application) for at-home bleaching with 4% hydrogen peroxide did not showed differences in color change and tooth sensitivity. Clinical relevance: Higher amount of active hydrogen peroxide in two daily applications for at-home bleaching neither accelerate bleaching nor increase the risk or intensity of tooth sensibility.
Article
This clinical study evaluated the effect of bleaching performed with violet LED light (405-410 nm), either combined with hydrogen peroxide (HP) gel, or not, on color change, dental sensitivity, participants' satisfaction and impact on their quality of life. A hundred participants were divided into one of the groups (n = 25): G1 - 35% HP (4 sessions, 1x/week); G2 - violet LED (4 sessions, 1x/week); G3 - violet LED (4 sessions, 2x/week); G4 - hybrid technique (violet LED + 35% HP; 4 sessions, 1x/week). Color evaluation was performed with colorimetric tests (objective and subjective), before, 14 days and 3 months after completion. Additionally, satisfaction with treatment, impact on quality of life (OHIP-14) and dental sensitivity were recorded. The data were submitted to statistical analysis, considering a significance level of 5%, with the exception of the data from the questionnaire on satisfaction (descriptive analysis). Two-way ANOVA and Tukey tests showed that there was no difference between color variation resulting from techniques used in G1 and G4; those used in G2 and G3 did not differ and were less effective for bleaching than those of the other groups, in both subjective and objective evaluations. Regarding tooth sensitivity, subjects in G2 and G3 experienced no sensitivity, while those in G4 showed lower sensitivity values than those in G1. With respect to quality of life, only subjects in G1 and G2 showed a significant positive impact. Among the evaluated techniques, the hybrid type seemed to be a good alternative, showing effective bleaching with less tooth sensitivity.
Article
Objective This study was aimed at comparing the bleaching efficacy and bleaching sensitivity (BS) of two higher-concentration in-office bleaching gels (37% carbamide peroxide [CP] and 38% hydrogen peroxide [HP]) applied under two conditions: alone or in association with sonic activation. Methods Fifty-six volunteers were randomly assigned in the split-mouth design into the following groups: CP, CP with sonic activation (CPS), HP, and HP with sonic activation (HPS). Two in-office bleaching sessions were performed. Color was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer at baseline and at 30 days post-bleaching. Absolute risk and intensity of BS were recorded using two pain scales. All data were evaluated statistically (color changes [t test], BS [Chi-square and McNemar test], and BS intensity [VAS; t test; NRS; Wilcoxon; α = 0.05]). Results Significant and higher whitening was observed for HP when compared with CP (p < 0.04). However, higher BS intensity was observed in the former (p < 0.001). No significant difference was observed in whitening effect or BS when the HP or CP bleaching gels were agitated (sonic application) compared with when they were not (p > 0.05). Conclusion The 37% CP gel demonstrated lower bleaching efficacy and lower BS compared with the 38% HP bleaching gel. The whitening effect was not influenced by the use of sonic activation. Clinical significance The use of 37% CP gel did not achieve the same whitening effect when compared to 38% HP gel used for in-office bleaching. The use of sonic activation offers no benefit for in-office bleaching.
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Objective: Our study aims to compare the efficacy and tooth sensitivity following in-office (35% hydrogen peroxide) or at-home (10% carbamide peroxide) bleaching treatments both preceded by 2% potassium nitrate (2%KF) desensitizing gel. Methodology: 130 volunteers were randomly allocated to a) in-office bleaching and a placebo at-home protocol; or b) in-office placebo and at-home bleaching treatment. 2% KF was applied for 10 min before both treatments. Objective: color evaluation was performed (spectrophotometer CIEL*a*b* system and CIEDE2000) to calculate the color change (ΔE00). Subjective evaluation was performed using the VITA classical shade guide followed by shade variation (ΔSGU) at the beginning and end of bleaching treatment and 2 weeks post-bleaching. Tooth sensitivity was daily recorded using a Likert scale varying from 1 (no sensitivity) to 5 (severe sensitivity). Analysis was carried out using non-parametric tests. Results: Regarding the color change, at-home bleaching resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.003) and Δa* (p=0.014). Two weeks post-bleaching, the at-home treatment resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.037) and ΔE00 (p=0.033). No differences were observed in either ΔSGU parameters. Concerning sensitivity, patients treated with in-office bleaching reported more tooth sensitivity than the at-home group only on the first day after bleaching started, without significant differences in the other periods evaluated (p>0.05). Conclusions: At-home and in-office bleaching, preceded by a desensitizing agent, were effective for vital teeth bleaching and 10% carbamide peroxide produced a higher whitening effect than 35% hydrogen peroxide in the short time evaluation. Tooth sensitivity rates were similar for the two techniques tested.
Article
Full-text available
When we observe the light reflected from surfaces in a scene or look directly at light emitted by light sources, we experience the sensation of color. Color is just one attribute of a complex and not fully understood set of properties that define the appearance of our surroundings. To measure or specify the color of an object, we need to take into account the nature of the light under which the object is viewed, the spectral reflectance properties of the surface, and the properties of the human color vision system. CLINICAL SIGNIFICANCE In this article the CIE system of colorimetry is briefly reviewed and its limitations are described.
Article
This clinical study compared the efficacy of three different bleaching techniques with respect to the bleaching times required in order to achieve six grades of whitening in human teeth. Any side effects that were noted and the patients' acceptance of the method were recorded by a visual analog scale ranging from 0 to 10. Moreover, epoxy casts from the study teeth were analyzed by scanning electron microscopy in order to detect any potential changes in the enamel surface due to treatments. Thirty-nine volunteers participated in the study and were allocated randomly to one of three different bleaching treatments: Group A (n=13) used Whitestrips (over-the-counter technique; one cycle=30 minutes), Group B (n=13) used Opalescence PF 10% (at-home bleaching technique; one cycle=8 hours) and Group C (n=13) used Opalescence Xtra Boost (in-office bleaching technique; one cycle=15 minutes) until a defined whitening of six tabs compared to the baseline were reached (assessed by the VITA shade guide). All three methods achieved six grades of whitening. The mean treatment time required to reach the defined level of whitening was 31.85 +/- 6.63 cycles in Group A, 7.15 +/- 1.86 cycles in Group B and 3.15 +/- 0.55 cycles in Group C. All products differed significantly from each other in terms of treatment cycles and required treatment time (p < 0.001 by ANOVA and Mann-Whitney-U-test). Using the VA scale, side effects noted within the three groups were minimal. Tooth hypersensitivity ranged from 2.62 (Whitestrips) to 3.38 (Opalescence PF), and gingival irritation ranged between 0.23 (Opalescence Xtra Boost) and 0.85 (Whitestrips). The most accepted method was the at-home bleaching technique. None of the teeth studied showed detectable enamel surface changes in the subsequent SEM analysis using 200x and 2000x magnification.
Article
Purpose: The purpose of this study was to evaluate the 2-year effectiveness of a carbamide peroxide at-home bleaching gel used to provide tooth lightening treatment. Material and Methods: Twenty-nine patients participated in the original study, during which they treated their maxillary teeth with a 10% carbamide peroxide gel nightly for 2 weeks. Shades were determined before and after treatment by comparison with a Vita shade guide. Twenty-four patients (a recall rate of 83%) were recalled for evaluation 2 years after the initial bleaching treatment. The shade of the maxillary incisors was evaluated and compared with shades before, immediately after, and at 6 months and 2 years after initial treatment. Data were analyzed using a repeated-measures analysis of variance. Results: At 2 years after bleaching with a 10% carbamide peroxide gel, the median shade was D2, a six-increment difference from the baseline median of D3. Twenty of 24 patients (83.3%) had a shade change of two or more units, which is the threshold value for bleaching efficacy using American Dental Association guidelines. The lightening result remained statistically significant (p <.0001) at 2 years.
Article
Purpose: Vital tooth bleaching has become a popular procedure for whitening teeth. Most home bleaching products contain 10% carbamide peroxide. The purpose of this in vitro study was to measure the quantity of hydrogen peroxide that reaches the pulp chamber from three carbamide peroxide products: Opalescence™, Sparkle™, and Rembrandt™. Materials and Methods: Seventy roots of extracted premolars were amputated approximately 3 mm apical to the cementoenamel junction, and the pulp tissues were removed. They were divided into three experimental groups (n = 20) and a control group of 10 teeth. An acetate buffer solution was placed in the pulp chamber before the crown was exposed to the bleaching agent at 37°C for 25 minutes. The buffer solution was removed and reacted with leukocrystal violet and horseradish peroxidase. The optical density of blue color that developed was measured at a wavelength of 596 nm and read from a standard curve for hydrogen peroxide quantity. Results: The measured amounts of hydrogen peroxide were 3.605 ± 1.405,1.282 ± 0.762, and 0.339 ± 0.251 pg for the Opalescence™, Sparkle™, and Rembrandt™ groups, respectively. A statistically significant difference in the hydrogen peroxide levels was observed by analysis of variance (p < .05) among the three groups. It was concluded that the penetration of commercial bleach ing products was different even though the products were labeled as having the same 10% carbamide peroxide.
Article
This double blind randomized clinical trial evaluated the longevity of the whitening effect (6-month follow-up) of two carbamide peroxide concentrations used in at-home vital bleaching. Ninety-two volunteers with shade mean C1 or darker for the six maxillary anterior teeth were randomized into two balanced groups (n=46) according to bleaching agent concentration: 10% (CP10) or 16% (CP16) carbamide peroxide. Patients were instructed to use the whitening agent in a tray for 2h/day during 3 weeks. Shade evaluations were done with a value-oriented shade guide, and a spectrophotometer at baseline, and at 1-week and 6-month post-bleaching. Volunteers for both treatment groups had to answer questions related to dietary and oral hygiene behavior. At 6-month recall, tooth shade remained significantly lighter than at baseline, in both treatment groups, considering the color parameters: DeltaL, Deltaa, Deltab, DeltaE (p<0.0001) or the tooth shade median values (p<0.001). Additionally, shade median relapse at 6-month follow-up was not statistically different between CP10 and CP16 groups using the spectrophotometer (p=0.1) or the visual matching (p=0.7) analyses. Overall, subjects from CP10 and CP16 reported high consumption of beverage and food stains, which was not different between groups (p=0.5). The whitening effect remained similar 6-month after the bleaching treatment for both carbamide peroxide concentrations tested. Additionally, the high consumption of staining beverages and foods reported by patients had no influence in the whitening effect longevity at 6-month.
Article
Tooth color change was monitored after a single, in-office bleaching technique using a colorimeter. Twenty young adults participated in the double-blind study at The Ohio State University College of Dentistry. Half of the participants had their maxillary anterior teeth bleached and half were controls. By one month, the large initial color change was considerably reversed and only noticed by one subject. After six months, the effect of bleaching was small, but still measurable.
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Two 10 cm visual analogue scales were compared with a 0-10 point numerical rating scale and a four-point verbal descriptive scale, in assessing pain severity in twelve patients with post-operative pain following removal of an impacted lower third molar. High correlations were shown between the pain scores from the two visual analogue scales and the numerical scale, but a lower correlation was obtained when the four-point scale was compared with the other scales. Analgesic efficacy was found to be dependent on the type of scale used. The 10 cm visual analogue scale was more sensitive than other pain scales and could discriminate between small changes in pain intensity.
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Visual color matching to determine shades in dentistry is inconsistent and unreliable. If accurate, instrumental measurement of tooth color would provide objective, quantified data to match natural teeth to clinical shade guides. This study evaluated and compared the ability of a new computerized colorimeter and a simple visual test to match ceramic shade guide teeth. Thirty-one (n = 31) observers with normal color vision were allowed unlimited time to match one set of Vita Lumin shade guide teeth to the corresponding shade guide teeth of a second Vita Lumin shade guide. The same test was administered to 14 of the observers several months later to determine within-subject variability. A computerized colorimeter (Colortron II) equipped with a positioning guide was used to measure the middle third of each shade guide tooth. Through a "match tool" present in the computer's software, readings from one shade guide were matched with readings of the other shade guide by using CIELAB measurements and DeltaE values. The mean number of correct matches by the colorimeter and of correct matches in visual test were compared with a 1-tailed t test. Repeatability for both tests was determined with a paired t test. The Colortron II instrument correctly matched 8 of the 16 tabs (50% correct), whereas visual matching by examiners averaged 7. 7 of 16 correct matches (48% correct) (standard deviation 2.7). No statistically significant differences existed between the 2 methods. The colorimeter demonstrated 100% repeatability and the visual test demonstrated fair repeatability (correlation coefficient r =.60). Shade determination by visual means was inconsistent. Accuracy of a new colorimeter in matching porcelain shade guide teeth was only slightly better.
Article
Vital tooth bleaching has become a popular procedure for whitening teeth. Most home bleaching products contain 10% carbamide peroxide. The purpose of this in vitro study was to measure the quantity of hydrogen peroxide that reaches the pulp chamber from three carbamide peroxide products: Opalescence, Sparkle, and Rembrandt. Seventy roots of extracted premolars were amputated approximately 3 mm apical to the cementoenamel junction, and the pulp tissues were removed. They were divided into three experimental groups (n = 20) and a control group of 10 teeth. An acetate buffer solution was placed in the pulp chamber before the crown was exposed to the bleaching agent at 37 degrees C for 25 minutes. The buffer solution was removed and reacted with leukocrystal violet and horseradish peroxidase. The optical density of blue color that developed was measured at a wavelength of 596 nm and read from a standard curve for hydrogen peroxide quantity. The measured amounts of hydrogen peroxide were 3.605 +/- 1.405, 1.282 +/- 0.762, and 0.339 +/- 0.251 micrograms for the Opalescence, Sparkle, and Rembrandt groups, respectively. A statistically significant difference in the hydrogen peroxide levels was observed by analysis of variance (p < .05) among the three groups. It was concluded that the penetration of commercial bleaching products was different even though the products were labeled as having the same 10% carbamide peroxide. Carbamide peroxide penetration to the pulp varies significantly for various commercial bleaching products. This may result in different levels of tooth sensitivity or bleaching efficacy.