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Clinical Performance of Vital Bleaching Techniques

Authors:
  • University of Minnesota

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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... Although bleaching efficacy of in-office technique has been demonstrated by several studies [6][7][8] , there are some concerns regarding the safety and possible side effects of hydrogen peroxide such as tooth sensitivity 9 , enamel alterations 10 , gingival or mucosal irritation 11 , reduction in enamel micro-hardness 12 , pulpal damage 13 , and deteriorative effects on the structure of restorative materials promoting decreased cell viability 5,14 . In addition, previous studies 15, 16 have revealed that adhesive application immediately after bleaching procedure adversely affects the bond strength which may be attributed to the morphologic alterations of enamel caused by hydrogen peroxide and the polymerization inhibition of resin adhesive systems due the presence of residual peroxide. ...
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The aim is to investigate the effect of resveratrol on micro-shear bond strength (µSBS) of adhesive to enamel after 40% hydrogen peroxide application. For µSBS test, 50 teeth were obtained, 2/3 of crowns were embedded into acrylic resin. After application of hydrogen peroxide twice, teeth were randomly allocated to control group and 9 groups (n = 15) according to concentrations (0.5, 1, 2 µM) and application periods (10, 30, 60 min) of resveratrol. Following, composite resin was placed onto enamel surfaces using 3 tygon tubes for each tooth. µSBS test was performed and failure modes were displayed. To analyze µSBS values, Kruskal Wallis and Mann-Whitney U tests were performed. µSBS values of 1 µM resveratrol for 10 min applied group were statistically higher than control group (p < 0.05). 1 µM resveratrol showed higher µSBS values than 0.5 µM and 2 µM (p < 0.05). No significant difference was detected between application periods (p > 0.05). The improvement of µSBS values with 1 µM resveratrol application may be promising for clinical problems related to reduced bond strength after bleaching.
... Tooth whitening has become a popular cosmetic dental procedure, with various methods available, including brushing, bleaching strips, pens, gels, and laser treatments [3]. The earliest tooth bleaching procedures were conducted in dental offices, with modern methods often utilizing high-concentration hydrogen peroxide, commonly known as "one-hour bleaching," ranging from 25% to 35% concentration [4,5]. ...
Article
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Patients have been recently observed to have undergone a noticeable increase in the concern over tooth discoloration making it a common cosmetic issue. This cumulative number of visits to dental experts is in search of ways to whiten their teeth because they desire to improve their looks. Often, the desire for a brighter smile is associated with health and beauty perceptions. Thus, patients tend to go after what they think is the perfect form of an unflawed grin. Diverse treatment modalities exist for tooth discolorations, such as composite laminate and veneers, porcelain veneers, and partial crowns. Amongst these options, bleaching, therefore, appears to be a conservative manner of dealing with teeth discoloration. This twin case report shows that discoloration can be managed best through bleaching using McInnes solution, resulting in good outcomes. Using McInnes solution instead makes bleaching an affordable and conservative technique for removing stains.
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Chapter
Smile is an integral part of facial aesthetics. This chapter provides a historical perspective of the evolution of the key components of an ideal smile and describes each in detail and how they relate to overall facial aesthetics. Prosthodontic and periodontal procedures to achieve this ideal outcome are discussed.
Article
Objectives Evaluate the bleaching efficacy (BE) and tooth sensitivity (TS) of in‐office bleaching using different application tips. Methods Forty‐eight participants were selected (split‐mouth), one to receive bleaching with an attached brush tip and one with a conventional tip. The procedure was performed with Whiteness Automixx Plus 35%. The BE was evaluated at the beginning, weekly, one and 12 months post‐bleaching with a Vita Easyshade spectrophotometer (Δ E * ab , Δ E 00 , and WI D ) and with Vita classical A1‐D4 and Vita Bleachedguide shade guides units (ΔSGU). Absolute risk and intensity of TS were recorded using the Visual Analogue Scale. The equivalence of BE was analyzed using the two one‐sided t ‐tests for paired samples. The absolute risk of TS was evaluated using the McNemar test, and the TS intensity was measured with the paired t test ( α = 0.05). Results The equivalence of BE was observed for both groups in all color evaluations ( p > 0.05). A lower absolute risk and intensity of TS were observed for the attached brush tip when compared with the conventional tip ( p < 0.003 and p < 0.0001). Conclusion Using an attached brush tip showed the same BE as a conventional tip. However, for the attached brush tip, there was a reduction in TS. Clinical Significance The applicator‐attached brush tip is recommended for in‐office dental bleaching, because of the possible reduction in risk and intensity of TS.
Article
Objective: The application of anti-inflammatories as topical desensitizers before dental bleaching is an approach to reduce bleaching-induced tooth sensitivity (TS). This randomized controlled trial compared the risk and intensity of TS and the color change resulting from in-office dental bleaching after using an experimental desensitizing gel containing ibuprofen and arginine. Methods: Sixty-two participants with upper canine shades A2 or darker were randomly assigned to either the ibuprofen-arginine desensitizing group or the placebo group. The desensitizing gel was applied for 15 min before in-office bleaching with 35 % hydrogen peroxide gel for 50 min (2 sessions). To assess the absolute risk and intensity of TS, visual (0–10) and numeric rating (0–5) scales were used, and group comparisons were made using the McNemar test, Wilcoxon test, and paired Student t-test (α = 0.05). Color change was evaluated using Vita Classical, Vita Bleachedguide (ΔSGU), and Vita EasyShade (ΔEab, ΔE00, and ΔWID) before and one month after the bleaching procedure. Group comparisons for color change were done using a paired t-test (α = 0.05). Results: The odds ratio for TS was 0.14 [95 % CI 0.02 to 0.6], meaning lower odds of TS for the desensitizing gel. A lower intensity of TS was also observed for the experimental group (p < 0.005) up to 48 h after bleaching. All color evaluation tools demonstrated effective and similar whitening for both groups (p > 0.05). Conclusions: Using the experimental desensitizing gel containing ibuprofen and arginine effectively reduced the risk and intensity of TS without compromising the bleaching efficacy. Clinical relevance: The topical application of ibuprofen/arginine on the in-office bleaching reduced risk and intensity of bleaching-induced tooth sensitivity.
Chapter
Although bleaching techniques are considered by many professionals and patients to be safe options for the treatment of tooth discolorations, the use of some bleaching products and techniques may have adverse effects on soft and hard dental tissues. This chapter will address the major complications related to the use of dentist-supervised at-home and in-office bleaching, as well as the use of over-the-counter products without professional supervision. In addition to the efficacy of different bleaching methods, the effects of bleaching agents on enamel, dentin, restorative materials, soft tissues, and tooth sensitivity will be objectively discussed based on the relevant peer-reviewed literature. Our goal is to discuss the rationale for adjusting the dosage recommended for different bleaching techniques according to each patient’s needs to make bleaching treatments safer. The side effects of peroxide-based bleaching treatments in the pulp tissue will be discussed in Chapter 5.
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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.
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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.