To evaluate the effectiveness of the laser diode on
bleaching colors changed t eeth under laboratory
conditions
Baharan Ranjbar Omidi
1
, Jamshid Poursamimi
2
and Kambiz Parvaneh*
3
1
Assistant Professor, Department of operative dentistry, dental caries prevention research center, Qazvin
University of medical sciences, Qazvin, Iran
2
Assistant Professor, Department of periodontology, dental caries prevention research center, Qazvin
University of medical sciences, Qazvin, Iran
3
Dentist, Ardebil, Iran
ABSTRACT
White teeth, are an important measure of beauty, and today, the use of laser tooth bleaching, is growing. The purpose of this study,
is evaluating the effectiveness of laser diodes, on whitening teeth, discolored previously by tea, coffee, and pomegranate juice pig-
ments. In this experimental study, 72 healthy bovine incisors were selected, were prepared, and were divided into three groups of
24 numbers. They were placed in a solution of tea, coffee and pomegranate juice, for two weeks. Each group was divided into two
sub-groups of 12, following the rst group; both groups were bleached by the bleaching gel 35%, and 940 nm diode laser. Laser
was applied to each tooth, with four cycles of 30 seconds, and the power of 7 watts. The second groups were bleached by 35% gel,
for 16 minutes as controls. Next, the teeth were stained measured by spectrophotometry. Data were entered into the software SPSS
version 20, and were analyzed using descriptive statistics, analysis and t-test, and ANOVA, with a signi cance level (p<0.05). After
placement of tooth colored materials (coffee, tea and pomegranate juice), three groups of pigments, creating signi cant color change
(0.000 P-value = in each group), the component (l, a, b). Most discoloration was created in coffee, and any change in the color of
pomegranate juice. Effectiveness of whitening discolored teeth, with and without laser diodes, showed no signi cant statistical dif-
ference (P-values≥0.05). In treatment groups, with and without laser, the highest effectiveness of bleaching (13.90 = ΔE with laser),
(11.31 = ΔE without laser) in the group tea, and least effective bleaching (6.51 = ΔE with laser), (5.85 = ΔE without laser) was obtained
in the group pomegranate juice. Regardless of the type of tooth discoloration, this study suggests that there is a relationship between
type of discoloration of enamel, and ef cacy of treatment of bleaching. 940 nm laser diodes did not increase the effectiveness of
catalytic bleaching.
KEY WORDS: BLEACHING, TEETH WHITENING, LASER DIODES
68
ARTICLE INFORMATION:
*Corresponding Author: kambiz_parvaneh@yahoo.com
Received 19
th
Dec, 2016
Accepted after revision 2
nd
April, 2017
BBRC Print ISSN: 0974-6455
Online ISSN: 2321-4007
Thomson Reuters ISI ESC and Crossref Indexed Journal
NAAS Journal Score 2017: 4.31 Cosmos IF : 4.006
© A Society of Science and Nature Publication, 2017. All rights
reserved.
Online Contents Available at: http//www.bbrc.in/
Biosci. Biotech. Res. Comm. Special Issue No 1:68-73 (2017)
Omidi, Poursamimi and Parvaneh
INTRODUCTION
Need to bleaching, in the population is growing. Con-
temporary bleaching systems are primarily based on
hydrogen peroxide, or one of its derivatives, which are
often established with liquid peroxide which is used in
different concentrations (Lagori et al. 2014). Bleaching
is de ned as a way to lighten the color of teeth using
organic oxidizing agents of pigment. Increased release of
hydroxyl radicals from hydrogen peroxide, with increas-
ing temperature is according to the following equation
(Pare and Loganathan, 2012).
H2O2+211KJ/Mol2HO
Bleaching reactions, is dependent on the chemical and
physical changes, during operation (concentration, tem-
perature, light, pH, co-catalyst, and duration) (Tano
et al. 2012).
Raising the temperature to C˚ 10 increases the hydro-
gen peroxide decomposition to x2.21. The use of light
sources such as laser (Light Ampli cation by strengthen-
ing and emitting a radiation) light hybrid (HL), halogen,
LED, plasma arc, and UV lamps are used to accelerate
the release of free radicals.First used wavelengths, were
argon laser (480 nm), and CO2 (10600 nm), but today
laser Diode (810 and 980 nm), and potassium phosphate
Titanil KTP (532 nm) are proposed too. Laser diodes are
used as well as pulsed or continuous, and have the wave-
lengths of 830, 810 and 980 nm. Diode laser has less
absorption of water and minerals of the teeth; they are
absorbed in pigments and have a lot of depth, in hard
tissue of teeth. Clearly, the best laser parameters, such
as power, wavelength, frequency, and duration of use
in dental treatment, totally depends on, different color
themes, tooth type, and change its color depends on the
skill and experience of the dentist , which should be
considered in reviews, as a key element (Nokhbe alfoga-
haei et al. 2012). Different types of lasers, they create
different effects, depending on the wavelength used, and
the type of material that causes discoloration, and each
wave laser, the whitening effect on a certain type of dye.
In fact, a particular type of bleaching gel, when coupled
with different lasers and different color elements, creates
dissimilar results (different) (Torres et al. 2011).
MATERIAL AND METHODS
After preparing freshly extracted teeth of cattle, and
washed with water and physiological solution, to split
between their teeth. Selected teeth healthy, and was free
of any cracks, decay and enamel defects. Root, cut from
the junction of the cement enamel, diamond bur, and
the pulp was removed. The teeth were kept for a week
for decontamination in 0.5% thymol solution. Teeth
brushing of the ori ce were closed, light-cured com-
posite. The teeth were randomly numbered from 1 to
72, and numbers were recorded in each tooth lingual,
by ne milling. Then color parameters were measured
in pigments, by a spectrophotometer (spectrophotom-
eter KONIKA MINOLTA Model CS-2000_ Japan) before
wrapping teeth (BS).The teeth have been prepared before
measuring the color. In this case, the rst four points
were prepared in Bacall level, just a quadrilateral the
dimensions of 5 x 5 mm, and at every step, measuring
the color of a part that was xed between points, done.
This is done by milling the ne of turbines. And then, a
speci c form for each tooth must be prepared, with the
proviso that, all templates are the same.
It should be noted that, at any time by spectropho-
tometer colorimetric, to enhance the accuracy of the
study is to determine the color of teeth in each series,
three consecutive colors was determined, and the aver-
age results achieved in statistical surveys and The evalu-
ation results was done.To stain teeth, 3 different types
of dye, tea, coffee, and pomegranate juice were used.
Instant tea Tea bags intensity using a number (Golestan-
Iran), in 250 ml of boiling water, the tea out of the water,
so cooler full of boiling water. 10 grams of soluble coffee
using coffee powder (Nestle - Switzerland), which is nor-
mally used for consumption, mixed in 250 ml of boiling
water, then it was ltered, and
Pomegranate juice, pomegranate seeds by mixing 50
grams in 250 ml of distile water, grains, were crushed
well in it, and then ltered solution was obtained (Lagori
et al. 2014). The teeth were immersed in the solution, so
that the numbers 1 to 24 in a mixture of tea, coffee 25
to 48, and 49 to 72 in pomegranate juice, were stored for
two weeks at 37 ° C (incubator ), and mixed daily. After
two weeks, the teeth out of solution and were washed
with brushes. Then, they were placed in physiological
solution, and again were measured by spectrophotomet-
ric color of the teeth (AS).
Bleach the teeth were prepared for the case that the
rst half of the teeth of each group were white using a
laser, and the second half without a laser. In the exam-
ples, along with laser bleaching: teeth were dried, and
a drop of 35% carbamide peroxide gels Pola of ce (SDI
Australia) were placed on each, and was broadcast by
micro-brush, as a uniform layer. Remained gel on the
teeth for about 8 minutes, and during this time, it was
under the in uence of diode laser radiation (laser diode
Biolase, model Epic10 940 nm wavelength, and the 7
watt United States), for each tooth, two 30-second cycle
with a rest period of one minute (power 7 w). After 8
minutes, the teeth were rinsed with water. And the pro-
cess was repeated. In total, on each of these examples,
the bleaching gel and laser for 2 minutes and 16 min-
utes were used according to manufacturer’s recommen-
BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS TO EVALUATE THE EFFECTIVENESS OF THE LASER DIODE ON BLEACHING COLORS CHANGED T EETH 69
Omidi, Poursamimi and Parvaneh
dations. In the examples, without using a laser bleach-
ing was: were dried teeth, and bleaching gel was placed
on each drop, and it was broadcast by Mykrvbrash, as
a uniform layer. Remained gel on the teeth for about
8 minutes. The teeth were washed with water, and the
process was repeated. And nally, the re-evaluation was
carried out by a spectrophotometer color. Evaluation of
color changes, (ΔE) were calculated and obtained by the
formula ΔE = (Δ L2 + Δ a2 + Δ b2) 1/2.
RESULTS
To study ndings, the color component data were col-
lected, and then entered in SPSS version 20, and then,
the analysis was performed assumptions.
Color parameters L, a, b, after exposing the pigment
of tea, coffee, and juice, have changed signi cantly.
(P-value = 0) (Table 1, 2, 3) Color parameters L, a, b,
changed signi cantly after the placement of the brown
pigment. Color parameters L, a, b, changed signi cantly
after exposure to Pigment pomegranate juice.
After placement of teeth in color, ΔE increased sig-
ni cantly, so that the greatest change was observed in
the group coffee, and any change colors in the group
Table 1. compares the color components before and
after exposure to tea
Color component mean
Standard
deviation
P-value
L before color
L after color
86.20
76.80
1.749
7.066
* 0.0
a before color
a after color
0.5036
4.573
0.6422
3.304
* 0.0
b before color
b after color
15.92
21.21
2.219
4.019
* 0.0
* Is signi cant (P-value ≤0.05).
Color parameters L, a, b, tea pigment after exposure, have changed
signi cantly.
Table 2. compares the color components before
and after exposure to coffee
Color component mean
Standard
deviation
P-value
L before color
L after color
87.98
75.08
2.006
6.046
* 0.0
a before color
a after color
0.5480
4.332
0.5403
1.695
* 0.0
b before color
b after color
13.96
19.56
2.370
2.914
* 0.0
* Is signi cant (P-value ≤0.05)
Color parameters L, a, b, after exposing the brown pigment, have
changed signi cantly.
Table 3. compared the relationship between color,
before and after exposure pomegranate juice
Color component Mean Standard
deviation
P-value
L before color
L after color
86.90
80.42
2.278
4.186
* 0.0
a before color
a after color
0.5453
3.187
0.6840
1.129
* 0.0
b before color
b after color
15.65
18.03
2.047
2.498
* 0.0
* Is signi cant (P-value ≤0.05)
Color parameters L, a, b, after the placement of the pigment
pomegranate juice, have changed signi cantly.
Table 4. Compare, ΔE before and after
bleaching the teeth, between the control
group and laser Tea
Group Mean
Standard
deviation
P-value
ΔE control 11.31 6.507
* 0.243
ΔE Laser 13.90 3.687
* Is not signi cant (P-value ≤0.05)
There was no signi cant difference in ΔE of teeth
discolored by tea, between control and laser,
(although ΔE in white with lasers, be higher).
Table 5. compared ΔE, before and after
bleaching the teeth, between the control
group and lasers, in coffee
Group Mean
Standard
deviation
P-value
ΔE control 10.53 4.102
* 0.099
ΔE Laser 13.80 5.136
* Is not signi cant (P-value ≤0.05)
There was no signi cant difference in ΔE of
discolored teeth, by coffee, between control and laser
(although ΔE in white with the laser above).
Table 6. compares the ΔE before and after
bleaching the teeth, between the control
group and laser pomegranate juice
Group Mean
Standard
deviation
P-value
ΔE control 5.851 4.486
* 0.673
ΔE Laser 6.510 2.887
* Is not signi cant (P-value ≤0.05)
There was no signi cant difference in ΔE of discolored
teeth, by the PJ, between control and laser (although
ΔE, in the White Group with lasers, be higher).
70 TO EVALUATE THE EFFECTIVENESS OF THE LASER DIODE ON BLEACHING COLORS CHANGED T EETH BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS
Omidi, Poursamimi and Parvaneh
pomegranate juice.Also it was observed statistically sig-
ni cant differences in ΔE of teeth discolored by tea, the
control group, and laser (p-value <0.05) (although ΔE in
white with the laser above). (Table 4). It was observed
statistically signi cant differences in ΔE of discolored
teeth, by coffee, between control and laser (p-value
<0.05), (although ΔE in the White Group by laser, was
higher). (Table 5) There was no signi cant statistical
difference in ΔE of discolored teeth, by Pomegranate
between the control group and lasers. (P-value <0.05)
(Although ΔE in white with lasers, be higher). (Table 6)
In the group, was done with laser bleaching, ΔE
between the three groups, discolored by tea, coffee, and
juice will be signi cantly different. (Table 7); the lowest
was in part due to discolored teeth with pomegranate
juice, and the most effective, was on teeth discolored
by tea, as it will, the difference was pomegranate juice
with both pigment of tea and coffee meaningful, and
the difference between tea and coffee, was not statisti-
cally signi cant.In the group, was done without laser
teeth whitening, ΔE discolored between the three groups,
with tea, coffee, and juice, was signi cantly different
(highest color change was observed in the group tea,
and any change colors, in the group pomegranate juice).
(Table 8)
DISCUSSION
Photons can have a signi cant impact on the molecule.
If a molecule can absorb a photon, it can be irritating or
even split apart. The bleaching process, needs to disinte-
grate, or transform molecules, which cause tooth discol-
oration. This process can take place, resulting in absorp-
tion of photons by molecules, or indirectly, by raising
the temperature of the gel and accelerate the produc-
tion of free radicals, and activate redox chemical reac-
tions, which leads from the disrupting dye molecules.
In this process, many free radicals are produced from
the decomposition of hydrogen peroxide, which is very
active in breaking the double bonds. Hydroxyl radicals
(OH) are the most powerful radicals. Many studies have
shown that, by increasing the production of hydroxyl
radicals, can achieve better results in tooth whiteners.
As I was indicating, optical and laser sources, cause
temperature rise of hydrogen peroxide, and accelerate
the formation of free radicals. Every 10 ° C increase in
temperature, accelerate the detachment of hydrogen per-
oxide bonds 2.2 times (Lagori et al. 2014).
On the other hand, we are faced with a multi-criteria
decision, to choose an appropriate, the dental bleach-
ing. Although the main objective is to achieve beauty
in bleaching, but signi cant effects on the patients
teeth are impossible to ignore. So, dentist in bleaching
is always faced with an interaction between beauty and
health, which are both important (Nokhbe alfoghahaei,
2012).
In the present study, bovine teeth were used for a
variety of reasons. No caries, and a better overall situa-
tion, which is consistent with the study. Providing more
convenient incisors cattle, towards humans, because
humans produce healthy incisor, the high number of
working problems. As well as physically for chemi-
cal similarity to human teeth (Schilke et al. 2000), and
(showing similar behavior in the process of bleach-
ing and staining, (Attia et al. 2009) Please refer to the
source).
In the present study, the colored components, l, a, b
after placing the samples in color, signi cantly changed.
Most discoloration (ΔE), was in the group coffee, then
tea, and any change in the color of pomegranate juice,
the result is similar to the study Lagori G, the biggest
change was the color of coffee (Lagori et al. 2014). Of
course, the shelf life of the dye solution, in the two-week
study, which is more than the Lagori G (a week).
In the present study, the use of 940 nm diode laser,
it can whiten signi cantly improved results, with 35%
hydrogen peroxide, was not in any of the groups com-
pared to the control group.
This result was similar to the results of previous stud-
ies Marson FC), Auschill TM, Sulieman M and Polydorou)
Table 7. Comparison with laser teeth whitening effectiveness
among the three color groups
Group Mean
Difference
P-value
tea Coffee
Pomegranate juice
0.108
7.39
0.998
*0.003
coffee tea
Pomegranate juice
0.108
7.29
0.998
*0.004
Pomegranate
juice
tea
coffee
7.39
7.29
*0.003
* 0.004
*Is signi cant (P-value ≤0.05)
Table 8. Comparison of bleaching teeth, no laser,
the three groups color
group
Mean
Difference
P value
tea
Coffee
Pomegranate
juice
0.783
5.46
0.887
*0.007
coffee
tea
Pomegranate
juice
0.783
4.68
0.887
*0.023
Pomegranate
juice
tea
coffee
5.46
4.68
*0.007
*0.023
*Is signi cant (P-value ≤0.05)
BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS TO EVALUATE THE EFFECTIVENESS OF THE LASER DIODE ON BLEACHING COLORS CHANGED T EETH 71
Omidi, Poursamimi and Parvaneh
(Auschill et al. 2005; Sulieman et al. 2005; Marson et al.
2008; Polydorou et al. 2013). But the result was different
with the results of clinical studies Zekonis R and his col-
leagues, who had applied bleaching agent, for a period
of 60 minutes on the teeth (Zekonis et al. 2003). Also, it
was different from the results Ozgul Baygin, the use of
980 nm diode laser with a power of 0.8 Watt and 1 Watt
for 30 seconds, and Whiteness HP was used as bleaching
agent, and concluded that, laser bleaching to increase
effectiveness. But the study Baygin, the teeth were not
dye the material, and the material was bleached and var-
ying concentrations (38%) (Baygin, 2012). According to
a study Wetter NU, the effectiveness of laser diode with
a bleaching agent Whiteness HP better than Opalescence
xtra. Also, 10 minutes had been used in the control
group or without laser which in this study; it increased
to 16 minutes, which can increase the effectiveness of
laser bleaching in groups (Wetter, 2004).
The results Lagori G, was somewhat different with the
study, so that the laser diode, only on teeth discolored by
coffee was effective, because of this difference, it could
be a different wavelength laser diode, in two studies,
and use of different bleaching agents (Lagori et al. 2014).
After bleaching, spectrophotometer, can detect very
small differences between the color of the teeth before
and after treatment. However, clinical outcomes are not
detectable to the eye until the ΔE not be higher than 3.
In the present study, in groups with and without laser,
in all pigments, after bleaching, ΔE was higher than 3.
The results of this study, the effectiveness of laser
bleaching, discolored between the three groups with tea,
coffee, and juice, were signi cantly different. The ef -
cacy was signi cantly observed in teeth, discolored with
pomegranate juice (6.510 = ΔE). There was no statisti-
cally signi cant difference between the effectiveness of
whitening teeth discolored by tea (13.90 = ΔE) and cof-
fee (13.80 = ΔE).These results were different from the
results Lagori G, which saw the lowest effective whiten-
ing laser diode, the Group of pigment coffee, and tea,
and the most effective laser diode on the pigment of
red fruits, the Department of red fruits of Lagori G, con-
sisting of a combination of pigments strawberries, rasp-
berries, and blueberries, which are not comparable with
pomegranate juice in this study. Regardless of colored
fruits, laser diode greatest effect was observed on tea
pigment, which is similar to the current study (Lagori
et al. 2014).
The results of this study, the effectiveness of bleach-
ing without the use of lasers, the Group discolored by
tea, was the highest, and it was lowest in the group
pomegranate juice (statistically signi cant difference
was observed between the groups of pomegranate juice
with tea and coffee) the result is similar to the study
Lagori G, the following groups of red fruits, the highest
ef cacy of bleaching was observed in the control group
(without laser) in the pigment tea (Lagori et al. 2014).
Although pomegranate juice group showed minimal
changes in pigment color during storage, after bleaching
(with and without laser), which showed the lowest result
in improved color. This result could be due to the acidity
of pomegranate juice, as reported in previous studies,
acidic drinks, causes loss of surface material, and cre-
ated more rough enamel, which it makes, more stable
materials color, and this change could reduce the effec-
tiveness of bleaching the surface (De Araújo et al. 2013).
CONCLUSION
1. After making tooth-colored material (tea, cof-
fee and juice), three groups of pigments, creating
signi cant color change (0.0 p-value =, in each
group). The greatest change in color was brown,
and the lowest color change was observed in the
group pomegranate juice.
2. In-all color groups (coffee, tea, and juice) the ef-
fectiveness of whitening teeth discolored, with and
without laser diode showed no signi cant differ-
ence.
3. In both groups, with and without laser, the lowest
ef cacy of bleaching was observed in discolored
teeth with pomegranate juice, and the most effec-
tive whitening, teeth discolored by tea.
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