Medical

Communication

Biosci. Biotech. Res. Comm. 10(3): 564-570 (2017)

Evaluation of two types of bleaching gel and light

source on whitening of teeth

Baharan Ranjbar Omidi

, Mohammad Nouri

and Negin Farahmandpour*

Assistant Professor, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences,

Qazvin, Iran

Dentist, Tehran Iran

Restorative Dentistry Specialist, Kermanshah, Iran

ABSTRACT

Today, increasing desire for tooth brightening, make bleaching gel and light sources as a popular method for tooth

whitening. The aim of this study was effect of combination of bleaching gel and light source on the teeth whitening.

In this study 60 healthy human anterior teeth were randomly dividedin three groups (n=20). The  rst groupwas with-

outlight, the second one LED andon the third group QTH light was used. Each group was divided into two subgroups

whichhad two types of hydrogen peroxide bleaching gelsincluding 37.5% Pola of ce and 40% Opalescence Boost

which were applied to them. The primary colors of teeth were measured, and then kept intea (200ml) for 7 days. After

that each tooth color was measured for the second time. The teeth were bleached according to the protocol of each

group: Immediately, after 3, 7 and 30 days they were measured by spectrophotometer. Data were analyzed by statisti-

cal software SPSS 20 and One-way ANOVA and Tukey testin alpha 0.05. Bleaching effectiveness of QTH signi cantly

was increasedin both of bleaching gels as compared to LED and without using of light, at different times: instantly,

3 days and 7 days after bleaching, a month after bleaching, signi cant differences between the different methods

was not seen. The results of this study showed thatin-of ce bleaching, with or without light is an effective method

of beaching. QTH Light in the short term (one week) showed signi cant impact on teethwhitening in both bleach gel.

However, within a month therewere no signi cant differences in all groups.

KEY WORDS: IN-OFFICE BLEACHING, HYDROGEN PEROXIDE, ACTIVATION LIGHT

564

ARTICLE INFORMATION:

*Corresponding Author: n.farahmandpour@gmail.com

Received 24

July, 2017

Accepted after revision 26

Sep, 2017

BBRC Print ISSN: 0974-6455

Online ISSN: 2321-4007 CODEN: USA BBRCBA

Thomson Reuters ISI ESC and Crossref Indexed Journal

NAAS Journal Score 2017: 4.31 Cosmos IF: 4.006

reserved.

Online Contents Available at: http//www.bbrc.in/

DOI: 10.21786/bbrc/10.3/34

Baharan Ranjbar Omidi et al.

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS EVALUATION OF TWO TYPES OF BLEACHING GEL AND LIGHT SOURCE 565

INTRODUCTION

In recent years, cosmetic dentistry has become an

important part of restorative dentistry. In all ages,the

teethappearances for patients are one of important

aspects which in uences on satisfaction of them.Desire

of having a whiter tooth has increased due to attention

of people to this novel that brighter teeth are healthier

and morestylish (Barghi, 1998). The bleaching is very

effective on teeth with high Hue and yellow tint (Ishi-

kawa‐Nagai, Terui, Ishibashi, Weber, & Ferguson, 2004).

In fact, dental bleaching materials are oxidizing materi-

als which difference in various techniques still stay con-

troversial (Izquierdo-Barba, Torres-Rodríguez, Matesanz,

& Vallet-Regí, 2015) .

Today, several bleaching methods are used includ-

ing: in-of ce professional, in-home professional (dentist

supervised take-home) and products without a prescrip-

tion (over-the-counter) (Caneppele, 2013). To speed up

the bleaching process, increasing the concentration of

chemicals or use different light devices recommended,

(Sulieman, Addy, MacDonald, & Rees, 2004), (Buchalla

& Attin, 2007). Some advantages of in-of ce techniques

like prevention of swallowing and contacting with oral

soft tissue, reducing treatment time and controlling of

the healing process make it as a suitable technique for

most patients compared to other techniques (Luk, Tam,

& Hubert, 2004), (Tay, Kose, Loguercio, & Reis, 2009).

Two important factors in estimating the teeth whiten-

ing product performance are peroxide concentration and

the duration of its application. Studies have shown that

higher concentrations of peroxide is required a smaller

amount of gel (Sulieman et al., 2004). In today’s in-

of ce bleaching carbamide peroxide and hydrogen per-

oxide are used mainly by heat or light-activated devices

to accelerate the process of bleaching teeth (Sulieman

et al., 2004), (Zhang et al., 2007). Most studies have sug-

gested that light cure accelerated the degradation of per-

oxide (by increasing temperature) which led to thefor-

mations of higher free radicals(Sulieman et al., 2004),

(Joiner, 2004), (Lima et al., 2009). today various light cure

devices like Light-emitting diode(LED), halogen lamp,

plasma arc lamp(PAC) are available, however, applica-

tion of heat, light or laser devices should not be more

than 5.5°C temperature due to preventing pulp chamber

damage(Buchalla & Attin, 2007). Although, in recent

years the use of laser bleaching is generally available as

an energy source but LED require nearly low cost, and less

energy (Kurachi, Tuboy, Magalhães, & Bagnato, 2001).

There is controversy about the effectiveness of different

light on teeth bleaching. although some researchers have

reported bene ts,however others showed no effects on

bleaching, (Ishikawa‐Nagai et al., 2004, Lima et al., 2009,

Polydorou, Wirsching, Wokewitz, & Hahn, 2013).

Polydorou et al. (2013) have reported that QTH is

more effective than laser bleaching, while Hahn et al.

(2013) did not investigate any improvement with LED

and laser in bleaching teeth. In another study which

evaluated six different light resulted that the diode laser,

QTH and LED had a signi cant impact on Teeth Whit-

ening (Domínguez et al., 2011) Similarly, Kossatz et al.,

compared effect of LED and laser on 35% hydrogen per-

oxide bleaching gel and reported no signi cant differ-

ences (Kossatz et al., 2011).

In another study where 35% hydrogen peroxide was

used, LED, QTH, plasma arc lamp, argon laser was used

and they have been reported no effect on tooth bleach-

ing (Lima et al., 2009). Clinician should be aware of any

risks regarding to bleaching process (Alqahtani, 2014).

The aim of this study was to evaluate effect of LED and

QTH light on teeth whitening, since using of any type

of light as an additional device is questionable in-of ce

bleaching.

MATERIAL AND METHODS

In vitro experimental study, the 60 human anterior teeth

were selected. First teeth were checked for any defects,

cracks, decays or  llings. Then selected teeth after scal-

ing, brushing (for 10 seconds with pumice and water

by prophylaxis rubber cup then cleaned with ultrasonic

cleaner, and stored for one week in the solution0.1%

Thymol at 4°C. While the entire of laboratory work used

gloves, surgical masks and face shields (Kohn et al., 2003),

(Kumar, Sequeira, Peter, & Bhat, 2005), (Lolayekar, Bhat,

& Bhat, 2007). The teeth were  xed in acrylic resin into

the mold which the angle of light cure is perpendicular to

the labial surface of the teeth. By creating four small holes

(depth of about 0.5 mm) with bur (No#1) created square-

shaped area (with dimensions of approximately 3 mm) in

the middle third of the labial teeth (Figure 1).

Labial surface of teeth were cleansed and brushed.

Then all the teeth stored in Ringer (Ringer’s Infu-

sion, Shahid Ghazi Pharmaceutical Co., Tabriz-Iran).

The teeth are completely dry with gauze and randomly

divided into three groups (20 = n) with different bleach-

ing protocols:The  rst group without light, the second

LED light cure system (Woodpecker Dental LED.D Cur-

ing Light, China), the third group QTH light cure system

(Coltolux 75 Curing Light-Coltene/Whaledent, USA).

Each group divided into two subgroups of 10 teeth the

 rst subgroup, hydrogen peroxide 37.5% Polaof ce +

(SDI, Australia) and in the second subgroup of hydrogen

peroxide 40% Opalescence Boost (Ultradent Products

Inc, South ordan, UT USA) was used ( gure 1).

The samples were placed on holder plate, white paper

Leneta. Light source positioned at an angle of 45 degrees

Baharan Ranjbar Omidi et al.

566 EVALUATION OF TWO TYPES OF BLEACHING GEL AND LIGHT SOURCE BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

FIGURE 1. Preparation of tooth for bleaching

to a line perpendicular to the surface and spectropho-

tometer device (KONIKA MINOLTA CS2000, Japan)

with an approximate angle of zero degrees relative to a

line perpendicular to the sample surface and they were

placed approximately 70 cm.

The device was set at 0.2 degrees. This angle makes

circular area with 2.4 mm in diameter in specimens.

Three measurements were taken for each sample and

average measurements were reported. Measurements

were conducted under laboratory conditions at approxi-

mately 25°C. The primary color of the teeth (M1) was

measured by spectroradiometer. for changing the color,

teeth were retained for 7 days in a mixture of tea (tea

bags Golestan) obtained by the method Sulieman et al

(Sulieman, Addy, & Rees, 2003). Teethwere brushed to

remove pigments.

Then the teeth color was measured for the second

time (M2). The teeth were bleached in all 3 groups

according to the protocol set for each group, while the

distance to the labial surface of the teeth were 5 mm to

light tip. The intensity of light rays was measured before

the start of each bleaching cycle using Radiometer (QTH

= 370mw/cm2, LED = 380mw/cm2) to ensure constant

light output is achieved at all stages of bleaching. In all

three groups, the use of bleaching gel and light were

performed exactly according to the manufacturer’s

instructions. A thin layer of (1 mm) Polaof ce bleaching

gel was placed on the labial surface of the teeth for 8

minutes, then using clean cotton it was cleansed by gel

then was stained with fresh gel.

This process was repeated three times (according to

the manufacturer’s instructions) and at the end all clear

gel, rinsed with water and dried and the bleaching gel

Opalescence Boost, a thin layer (mm1) of gel on the

labial surface of teeth put for 20 minutes (according to

the manufacturer’s instructions) and at the end all clear

gel, rinsed with water and dried. Light application in

groups 2 and 3 were three 8-minute for Polaof ce and a

20-minute period to Opalescence Boost.

Tooth color was measured immediately after bleach-

ing (M3). Samples were put on Ringer with 37 ° C which

switching with new Ringer every day then he teeth color

were measured after 72 hours (M4), 1 week (M5), one

month (M6). All stages of tooth color measurement sys-

tem were performed by spectrophotometer according to

CIE L*a*b* (Commission Internationale de I’Eclairage’s)

(Tavares et al., 2003). According to the ADA (American

Dental Association) tooth color measurement, device

located in the middle third of the labial surface of the

teeth ( gure 2).

Tooth bleaching ΔE values are directly in uenced

by the index tooth color difference between the initial

measurement and other measurements are shown and

using the formula: E = [(ΔL *) 2+ (Δa *) 2+ (Δb *) 2] 1 / 2Δ

(Δa = a * post - a * baseline, Δb = b * post - b * baseline,

ΔL = L * post - L * baseline) was achieved. Data were

collected with 20 SPSS statistical software and ANOVA

test value of P (P<0.05) were obtained and studied under

Tukey test was used pairs of groups.

RESULTS AND DISCUSSION

ΔE averages and standard deviations for all groups and

in all stages after bleaching compared to after being in

tea shown in Table 1.

Baharan Ranjbar Omidi et al.

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS EVALUATION OF TWO TYPES OF BLEACHING GEL AND LIGHT SOURCE 567

Signi cant difference between ΔE of groups (at times

immediately, three days and one week after white) one-

way ANOVA test was observed ( P-Value <= 0.05). ΔE

signi cant difference between the groups was observed

one after month the bleaching. (P = 0.57)

Comparing of pairs of groups by test Tukey, both of

bleaching, a signi cant difference in the effectiveness

of bleaching (ΔE) with the use of light QTH compared to

LED and without the use of light (in the time immedi-

ately after bleaching, three days and 7 days after bleach-

ing) showed that although a month later bleaching of

teeth whitening showedsigni cant difference in ef cacy

between any of these groups (Table 2).

To achieve lightening of teeth in a short time, bleach-

ing technique in the of ce, using a high concentration

hydrogen peroxide gel, with and without the use of light

is recommended (Luk et al., 2004), (Roberto et al., 2011).

Some studies have emphasized that light can be used

to catalyze the hydrogen peroxide, thus accelerates the

bleaching process (Dostalova et al., 2004), (Tavares et al.,

2003). This issue is still discussed in articles and reviews.

In the present study, the teeth ΔE after tea, signi cantly

increased (ΔE in all groups was higher than 3.3 means

the discoloration caused by tea in all groups were detect-

able by eye) ΔE, difference before and after exposure to

tea among all groups was not signi cant.

In this study, ΔE changes in groups (immediately, three

days and one week after bleaching), was signi cant,so

the applicationof Polaof ce with QTH showed whitening

effect. In the present study, the Tukey test results showed

that in both bleaching agent (Opalescence and Pola

of ce), QTH Light application signi cantly increased the

effectiveness of bleaching component compared to LED

or without light, immediately after bleaching teeth, 3 days

and 7 days after bleaching, Because QTH heat transfer

capability to the teeth is more than LED. QTH produce

more heat than light on the tooth surface which can form

groups that cause more tooth dehydration (Liang et al.,

2012). Also, previous studies which have examined differ-

ent types of light reported that QTH effect was remarkably

higher in immediately after bleaching (Sulieman et al.,

2005, Polydorou et al., 2013 Liang et al., 2012).

FIGURE 2. Evaluation of samples by spectrophotometer

Table 1.

1 month after

bleaching

7days after

bleaching

3 days after

bleaching

Immediately after

bleaching

Groups

6/74 (1/12) 3/92 (0/82) 4/95 (0/9) 3/8 (0/57) Polaof ce+without light

9/83 (2/78) 3 (0/8) 3/82 (0/77) 2/89 (1) Opalescence Boost without light

7/25 (0/88) 4/78 (0/49) 5/39 (0/58) 3/57 (0/56) LED Polaof ce+

7/17 (1/08) 98/3 (0/53) 4/21 (0/37) 3/28 (0/54) LED Opalescence Boost

6/58 (1) 10/84 (1/11) 10/3 (1/09) 8/82 (1/21) QTH Polaof ce+

6/32 (0/81) 8/44 (0/45) 8/08 (0/45) 7/28 (0/4) QTH+Opalecensce Boost

Signi cant difference between ΔE of all groups after being in tea using one-way ANOVA test was observed. (P = 0.47)

Baharan Ranjbar Omidi et al.

568 EVALUATION OF TWO TYPES OF BLEACHING GEL AND LIGHT SOURCE BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

In this study, ΔE difference was not statistically sig-

ni cant a month after bleaching,in all groups, ΔE was

more than 3.3 which teeth bleaching was still detectable

after a month with eye. Tukey test results compare pairs

of groups after one month however no signi cant dif-

ference was observed between ΔE. This means that after

a month no statistically signi cant differences between

the different methods of bleaching as observed similar

results from studies have concluded the same, (Poly-

dorou et al., 2013) and (Alomari & El Daraa, 2010).

In this study, all groups showed obvious effect imme-

diately after bleaching, though there is noconsiderably

differences between one and three months. Although

some studies have reported the effects of light on tooth

whitening (Luk et al., 2004), (Domínguez et al., 2011),

(Ontiveros & Paravina, 2009), (Wetter, Barroso, & Pelino,

2004), but many studies have focused Light extremely

ineffectiveness on teeth whitening (Lima et al., 2009),

(Polydorou et al., 2013), (Roberto et al., 2011),(Bernardon

et al., 2010), (Marson, Sensi, Vieira, & Araújo, 2008),

(Mondelli, Francisconi, Almeida, & Ishikiriama, 2012),

(Hein et al., 2003), (Papathanasiou, Kastali, Perry, &

Kugel, 2002).

Although, in this study QTH had greater effectiveness

after 7 days, but after one month treatment relapse was

observed. In Polydorous study, the use of QTH for each

tooth was 4times in 8 minutes (Polydorou et al., 2013),

while in Liangs study, two sessions with7 days interval

3 times of 10 minute were applied (Liang et al., 2012).

So in both of these study groups, teeth were exposed

longer to QTH light. Relapse in treatmentin the Poly-

dorous study only occurred in a month after treatment

QTH group (Polydorou et al., 2013), which is similar to

the results of our study, while both groups in the Liangs

study showed relapse after a week with or without light

cure system (Liang et al., 2012).

For other groupsin the Polydorous study, relapse

occurred after 3 months (Polydorou et al., 2013), while

in Liangs it happened sooner (Liang et al., 2012). These

results can be explained by a lower concentration of

bleaching agent used in study (32% Beyond II Advanced

Formula Whitening Gel) compared with current study

(37.5% Polaof ce and 40% Opalescence Boost) and

Polydorou study (38% Opalescence Boost), although this

difference is negligible. Tooth dehydration can cause

brighter teeth immediately after bleaching so this can be

increased by the heat transferred to the teeth (Luk et al.,

2004). Tooth color becomes lighter during dehydration

however returning to normal mode after rehydration.

During in-of ce bleaching, many factors could cause

dehydration teeth, including teeth isolation, heat from

the light (Liang et al., 2012).

According to the results of this study at any time

after the teeth bleaching, a signi cant difference in the

effectiveness of the bleaching was observed regardless

of light cure application, Which could be due to the

concentration of these two bleaching gel (37.5% Pola

of ce + and 40% Opalescence Boost). Also, according

to the manufacturer’s instructions, each of bleaching

gel which hadless concentrations, longer exposure in

the tooth surface (37.5% Polaof ce 3 times for 8 min-

utes and 38% Opalescence Boost only 20 minutes)so the

effectiveness of bleaching materials weresimilar. Scien-

ti c community believe that light cure bleaching effec-

tiveness occurs due to reversible dehydration (Polydorou

et al., 2013) so in long-term we should expect relapse

of treatment. The results obtained in this study during

a month is not only con rmed the stability of tooth

Table 2.

GroupsP-value

Immediately

P-value

After3 days

P-value

After 7days

P-value

After one

month

Polaof ce with Opalescence Boost Without light 0.450. 350. 440.31

Polaof ce with Opalescence Boost LED0.710.10. 280. 95

Polaof ce with Opalescence Boost QTH0.240.080. 080. 84

Without light Polaof ce + LED Polaof ce+0.980.930. 750. 93

Without light Polaof ce + QTH + Polaof ce*0.001*0.001*0.000. 99

Polaof ce + LED with QTH + Polaof ce +*0.00*0.002*0.000. 89

Without light + Opalescence Boost LED + Opalescence Boost0.920.870.50. 55

Whithout light + Opalescence Boost QTH + Opalescence Boost*0.001*0.00*0.000. 36

LED + Opalescence Boost QTH + Opalescence Boost*0.001*0.00*0.000. 94

ΔE Changes in groups at different times after bleach in arein Charts 1, 2 and 3.

Baharan Ranjbar Omidi et al.

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS EVALUATION OF TWO TYPES OF BLEACHING GEL AND LIGHT SOURCE 569

color But also enhances the white color of the teeth in

both LED and without light cure system. The Greenwall

hypothesis is that during bleaching, teeth get aerated by

oxygen and oxidation processes caused by dehydration

change the visual characteristics of the teeth. This partly

is explained why teeth become whiter in this study after

a month. For this reason, after a two-week period, scat-

tered oxygen rehydrate and teeth show their true colors

(Greenwall, 2001).

While in current study, the majority of teeth bleached

within a month except QTH group which heat lead

to improve the effectiveness of treatment in few  rst

days,another parameter that can affect the outcome of

the study is the viscosity of bleaching gel. Opalescence

Boost was replaced with Opalescence Xtra Boost some

time ago, although, manufacturer claim no chemi-

cal change, but the foundation and consistency has

changed; the new bleaching gel is more viscous than

before. The composition and sticky bleaching gel affect

on the release of hydrogen peroxide which impact on

bleaching process (Christian Hannig, Weinhold, Becker,

& Attin, 2011), (Hannig, Zech, Henze, Dreier, & Attin,

2005), (Thitinanthapan, Satamanont, & Vongsavan,

1999). high viscosity bleaching agents compared to low

one shows higher peroxide emissions (Christian Hannig

et al., 2011).

This change in viscosity after bleaching can cause

different behavior because the viscosity of the material

affects the free movement of peroxide (peroxide release

kinetics). The clinical perspective, highlights light cure

effect on the con dence and satisfaction of patients to

continue bleaching. After a month there was no signi -

cant difference between the three groups and this shows

that bleaching by light relapse sooner and do not main-

tain long-term effect.

CONCLUSION

According to data obtained from this study, the fol-

lowing results can be obtained. In of ce- bleaching,

with and without light, is effective to bleach teeth.

In both type of bleaching, bleaching effectiveness of

QTH increases signi cantly compared to LED and with-

out the use of light, at times of instantly, 3 days and 7

days after bleaching.Light cure does not lead to increase

effectiveness of bleachingwithin a month.

REFERENCES

Alomari Q, El Daraa E. 2010 A randomized clinical trial of in-

of ce dental bleaching with or without light activation. Con-

temp Dent Pract. 11:17–24.

Barghi N. 1998 Making a clinical decision for vital tooth

bleaching:At-home or in-of ce? Compendium Continuing

Educationin Dentistry 19(8): 831-838.

BernardonK,Sartori N, Ballarin A, Perdigão, Lopes GC, Bara-

tieri LN. 2010 Clinical performance of vital bleaching tech-

niques. Oper Dent. 35:3-10.

Buchalla W, Attin T.2007 External bleaching therapy with acti-

vation by heat, light or laser: a systematic review. Dent Mat

23: 586- 96.

Domínguez A, García A, CostelaA,Gómez C. 2011 In uence of

thelight source and bleaching gel on the ef cacy of the tooth

whiteningprocess. Photomed Laser Surg 2011; 29: 53-9.

Dostalova T, Jelinkova H, Housova D, Sulc J, Nemec M, Miyagi

M 2004 Diode laser activated bleaching. Braz Dent J 15:3-8.

Greenwall L. 2001 Bleaching Techniques in Restorative Den-

tistry. London: Martin Duntz Ltd

Hahn P, Schondelmaier N, Wolkewitz M, Altenburger M, Poly-

dorou O. 2013 Ef cacy of tooth bleaching with and without

light activation and its effect on the pulp temperature. Odon-

tology.2013 Jan;101(1):67-74.

Hannig C, Weinhold HC, Becker K, Attin T. 2011 Diffusion

of peroxi des through dentine in vitro with andwithout prior

use of a desensitizing varnish. ClinOralInvestig 15(6) :863-

868.

Hannig C, Zech R, Henze E, Dreier S, Attin T.2005 Peroxide

release into saliva from  ve different homebleaching systems

in vivo. Am J Dent.18(1): 13-18.

Hein DK, Ploeger B, Hartup K, Wagstaff RS, Palmer TM, Hansen

LD.2003 In-of ce vital tooth bleaching - what do lights add?

CompendContinEduc Dent. 24:340-52.

Ishikaw-Nagai S,TeruiT,Ishibashi K, et.al. 2004 Prediction of

optical ef cacy of vital tooth bleaching using regression anal-

ysis. Color Research and Application 29:390-4

Joiner A. 2004 Tooth colour: a review of the literature. Den-

tistry 32:3-12.

Kohn WG, Harte A, Malvitz DM, Collins AS, Cleveland

L, Eklund K; Centers for Disease Control and Prevention.

CDC.2004 Guidelines for Infection Control in Dental Health-

Care Settings-2003. Am Dent Assoc. 2004 Jan;135(1):

33-47.

Kossatz S, Dalanhol AP, Cunha T, Loguercio A, Reis A.2011

Effect o ight activation on tooth sensitivity after in-of ce

bleaching. OperDent 2011; 36: 251-7.

Kumar M, Sequeira PS, Peter S, Bhat GK. Sterilisation of

Extracted Human Teeth for Educational Use. Indian J Med

Microbiol 2005;23(4):256-258.

Kurachi C, Tuboy AM, Magalhães DV, Bagnato VS. 2001 Hard-

ness evaluation of a dental composite polymerizedwith experi-

mental LED-based devices. Dent Mater 2001; 17: 309–15.

Liang S., Y Sa, L Sun,X Ma, Z Wang, W Xing 2012 Effect of

halogen light irradiation on hydrogen peroxide bleaching: an

in vitro study. Australian Dental Journal. 57: 277–283.

Lima DA, Aguiar FH, Liporoni PC, Munin E, Ambrosano

GM,Lovadino R. 2009 In vitro evaluation of the effectiveness

of bleachingagents activated by different light sources. Pros-

thodont 2009; 18: 249-54.

Baharan Ranjbar Omidi et al.

570 EVALUATION OF TWO TYPES OF BLEACHING GEL AND LIGHT SOURCE BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

Luk K, Tam L, Hubert M. 2004 Effect of light energy on perox-

ide tooth bleaching. Am Dent Assoc. 135:194-201.

Marson FC, Sensi LG, Vieira LC, Arauo E. 2008 Clinical evalu-

ation of in-of ce dental bleaching treatments with and with-

out the use of light-activation sources. Oper Dent. Jan-Feb;

33(1):15-22.

Mondelli RF, Azevedo F, Francisconi AC, Almeida

CM,Ishikiriama SK. 2012 Comparative clinical study of the

effectiveness ofdifferent dental bleaching methods - two year

follow-up. ApplOral Sci. 20(4):435-43.

Nikita V Lolayekar, Vidya Bhat S, Sham S Bhat. 2007 Distin-

fection Methods of Extracted Human Teeth. Oral Health Comm

Dent 2007;1(2):27-29.

Ontiveros C, ParavinaRD.2009 Color change of vital teeth

exposed to bleaching perfomed with and without supplemen-

tary light. Dent. 37:450-7.

Papathanasiou A, Kastali S, Perry RD, Kugel G.2002 Clinical

evaluation of a 35% hydrogen peroxide in-of ce whitening

system.CompendContinEduc Dent. 23:335-8.

Polydorou O, Wirsching M, Wokewitz M, Hahn P. 2013 Three-

monthevaluation of vital tooth bleaching using light units:

a randomizedclinical study. Oper Dent.2013 Jan-Feb; 38(1):

21-32.

Roberto AR, Jasse FF, Boaventura JMC, Martinez TC, Rastelli

ANS, Junior OB 2011 Evaluation of tooth color after bleach-

ing with and without light-activation. Rev OdontoCienc.

26(3):247-252.

Sulieman M, Addy A, Rees JS. 2003 Development and eval-

uation ofa method in vitro to study the effectiveness of

toothbleaching. J Dent. 31:415-22.

Sulieman M, Addy M, MacDonald E, Rees S. 2004 The effect

of hydrogen peroxide concentration on the outcome of tooth

whitening: an in vitro study. Dentistry 32: 295-9.

Sulieman M, MacDonald E, Rees S, Addy M.2005 Comparison

of three in-of ce bleaching systems based on 35% hydrogen

peroxide with different light activators. Am Dent.18:194-7.

Tavares M, Stultz J, Newman M, Smith V, Kent R, Carpino

E 2003 Light augments tooth whitening with peroxide. J Am

Dent Assoc 134:167-75.

Tay LY, Kose C, Loguercio AD , Reis A. 2009 Assessingthe effect

of a desensitizing agent used before in-of cetooth bleaching

ournal of the American Dental Association 140(10):1245-1251.

Thitinanthapan W, Satamanont P, Vongsavan N 1999 In vitro

penetration of the pulp chamber by three brandsof carbamide

peroxide. J Esthet Dent. 11(5):259-264

Wetter NU, Barroso MC, Pelino EP. 2004 Dental bleaching ef -

cacy with diode laser and LED irradiation: an in vitro study.

Lasers Surg Med. 35:254-8.

Yap AU, Soh MS.2003 Thermal emission by different light

curingunits. Oper Dent 2003; 28: 260–6.

Zhang C, Wang X, Kinoshita 2007 Effects of KTP laser irradia-

tion, diode laser and LED on tooth bleaching: a comparative

study.Photomed Laser Surg 2007; 25: 91-5.