international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
evaluation the effect of in-office bleaching on
color changes on restorative composite resins
ameer al-ameedee1, hala ragab2, ziad salameh3, essam osman4
1faculty of dentistry, beirut arab university, lebanon, babylon university, hila, iraq
2faculty of dentistry, beirut arab university/lebanon
3school of dentistry / lebanon university /beirut/lebanon
4faculty of dentistry, beirut arab university
abstract: this study evaluated the vitro performance of the effect of in-office bleaching (zoom gel material) on the color changes of
the one hundred twenty discs specimens, 5 mm in diameter and 2 mm thickness and shade color (a1).these were divided to three groups
according to material which prepared from beautiful ii (b), isp empress direct (e) and ceram.x.mono composite resins (c), each
group s discs specimens were subdivided into four subgroups (n=10), according to the time follow up. all specimens’ discs were polished
and stored in distilled water at 37°c for one week. these specimens discs were exposed later to four sessions of in office bleaching. the
colorimetric measurements were performed at baseline (before bleaching), 48 hours after bleaching, 3 months and 6 months after
bleaching. data statistically analyzed. results showed: there were significant effects on the different color parameters l*, a* and b*
according to the cie l* a* b* color system and color change (?e) on the specimens of the three contemporary composite resins
materials.
keywords: restorative composite color changes, in-office bleaching gel, cie l* a* b* color system, beautifil ii composite resins, isp
empress direct composite resins and ceram.x.mono composite resins.
1. introduction
the esthetic goals of our patients and dentistry today have
become increasingly demanding the use of composite resins
as tooth composite resin to achieve the optical properties of
natural teeth. the aesthetic appearance of anterior teeth has
become a major concern for patients. discolored vital
anterior teeth have long treated with different approaches
including crowns, direct and indirect veneers, composite
resin composite resin, and most conservatively bleaching.
both take-home and in-office bleaching techniques have
proven effective results in whitening teeth with the latter
having the advantage of producing immediate results [1],[
2].
the bleaching agents are able to provide tooth color change
and, at the same time, may yield color and surface
alterations of resin composite resin existed on teeth. the
response of resin composites to the whitening materials is
associated with the type, the concentration of bleaching
agent and the total bleaching time the available products
concerning the effect on color and on surface properties of
aesthetic materials are expected, the effects of bleaching
regimens on the color and gloss of resin composites had
adequately investigated [3], [4], [5]. kim et al, they revealed
that tooth whitening causes negligible alterations on the
color and the surface of a nano filled and two micro-hybrid
resin composites [6].
the type of the resin composite in terms of composition in
organic and inorganic phase has detected as a crucial factor
for the degree of color and surface alterations induced by the
bleaching products [7], [8], [9], [10], [11] and [12]. resin
materials are especially more prone to chemical alteration
compared to inert metal or ceramic composite resin [13],
[14] and [15]. in addition, composite resins tend to discolor
teeth due to their resin matrix hydropinghilicity and water
absorption properties. thus, the degree of discoloration may
lead the patient and the dentist to replace composite resin
composite resin over time [16]. the typical in-office
bleaching regimen involves application of a high percentage
hydrogen peroxide formulation either to the teeth surfaces,
which activated chemically or by a light source. the
theoretical advantage of using lights was their ability to heat
hydrogen peroxide, thereby enhancing the rate of oxygen
decomposition. the oxidation in which the molecules
causing discoloration are chemically modified [17]. the
increased amount of oxygen-free radicals produced thus
enhances the release of stain-containing molecules and,
therefore, results in enhanced whitening [18], [19].
among many reports concerning the effects of in-office
bleaching on natural teeth, and its effect on tooth-colored
composite resin is not, yet, fully known. the resin
composites are widely used as restorative materials because
of their excellent aesthetic properties. however, their initial
color may change over time because of surface and marginal
staining, as well as internal material deterioration [20], [21].
discoloration can be evaluated with various instruments.
instrumental colorimetric, used in the present investigation,
can eliminate the subjective interpretation of visual color
comparison [22]. in this study, color measurements were
performed by stereomicroscope using the cie (commission
internationale de i’ eclairage) l*a*b* color system. color
measurements were assessed utilizing (l*) value. the major
parameter causing the color change was found to be (l*)
rather than the chroma (a* and b*) [23].
the purpose of this study was to determine the different
color parameters l*, a* and b* according to the cie l* a*
b* color system and ?e color change of three nano filled
composites when subjected to in-office bleaching technique
paper id: 02013454 77
international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
using zoom gel material. the null hypothesis was that the
three-nano filled composites would respond similarly to the
bleaching agent.
2. material and methods
three groups (n=40 discs) of resin composites specimens:
beautifil ii [bisphenylglycidyl dimethacrylate (bis-gma),
7.5% triethylenglycol dimethacrylate (tegdma), 5%
aluminofluoro, 70% al2o3 (borosilicate glass). dlcamphorquinone,
(shofu dental corporation, usa)]. isp
empress direct [paste of dimethacrylates, copolymer 20-
21%wt, barpum glass 77.5-79%wt, ytterbium trifluoride
(550nm), initiators, stabilizers and pigments,(ivoclar
vivodent, usa)]. ceram.x.mono [methacrylate modified
polysiloxane, dimethacrylate resin, ba-al-borosilicate glass
70%, pyrogenic sio257% , camphorquinone, ethyl-4-
diemthylamino benzoate, uv stabilizer, butylated hydroxy
toluene, (detrey, dentsply, germany)] composite resin
specimens, these three resin composites used in this study.
each group specimens was subdivided into four subgroups
according to the time follow up (n=10, shade a1). each disc
specimen was prepared by using cylindrical teflon mold
length 2mm and width 5mm, the resin composite put as one
increment, and light cure to polymerized from each side for
40 seconds using a light unit (gnatus, fotopolimerizador
optilight plus, brasil) with intensity of 350 mw/cm2 then
polished with sof-lex system (3m espe, company). all
composite resin groups’ discs specimens were stored in
distilled water at 37°c for one week to complete their
polymerization, and then subjected to in-office bleaching for
four sessions according to the manufacture instructions. the
measurements recoded according to timetable as shown in
table 1.
the test measures l*, a*, and b* color space and this system
are referred to as ciel*a*b*. in the color space, l*indicates
lightness (l*+=lightness and l*-= darkness), the
a*coordinate represents the red/green range (a*+=redness
and a*-=greenness) and the b* coordinate represents for the
yellow/blue range (b* + = yellowness and b* - = blueness).
the values of the coordinates a* and b* approach zero are
indicating neutral colors (white and gray) and an increase in
magnitude for more saturated or intense colors [24]. color
evaluation performed using a vita easy shade
spectrophotometry which expresses color coordinates
according to the cie l* a* b* color system. other methods
of color determination had been used in dentistry, including
visual assessment with the instrumental methods generally
considered more precise as they eliminate subjective errors
[25].
more importantly, the cie l* a* b* color system is widely
popular and developed for characterization of colors based
on human perception. this system color difference value,
?e is expressed as a relative color change between
successive color measurements. it generally agreed that a
value of ?e ? 3.3 considered clinically perceptible [24],[25],
[26], [27]. the l*a*b*system allows the numeric definition
of a color as well as the difference between two colors
values were obtained using the hunter’s equation (central
bureau of the international commission on illumination
colorimetric cie publication. vienna, austria: 1986)
following formula:
?e= [(l1 – l0)2+ (a1 – a0)2 + (b1 – b)2]1/2.
the change in color from baseline compared to the color
after 48 hours of the bleaching was calculated (?e1). the
change in color of the 3-months after bleaching compared to
the color after48 hours of bleaching was also calculated
(?e2). the change in color after 6-months of the bleaching
compared to the color after 3-months was also calculated
(?e3).
2.1 statistical analysis
a randomly selected sample from each treatment group was
used to examine color changes. this assessment was
performed using a vita easy shade. the measurements data
of color changes were collected, tabulated and statistically
analyzed. data were presented as mean, standard deviation
(sd) which is a measure of variation between values, which
is a measure values. lde post hoc test was used for pairwise
comparison between the means when the anova test
is significant. the significance level was set at p = 0.05.
statistical analysis was performed with spss 20.0
(statistical package for scientific studies inc., chicago, il,
usa) for windows.
3. results
3.1. the effects of bleaching on the three composite resin
group’s specimens discs
where are ?l*, ?a* and ?b* values: its color differences’ in
the cie l* a* b* color space
if ?l*+: means specimen after is lighter than before during
time follow up.
if ?l*?: means specimen after is darker than before during
time follow up.
if ?a*+: means specimen after is redder than before during
time follow up.
if ?a*?: means specimen after is greener than before
during time follow up.
if ?b*+: means specimen after is yellower than before
during time follow up.
if ?b*?: means specimen after is bluer than before during
time follow up.
if ?e: ? 3 means specimen recognizes for human eyes view.
results showed there were highly significant differences in
the cie l* a* b* color space means values for all-time
follow up among the three groups composite resin
specimens discs that means there were differences on l* a*
b* color space among those groups.
results showed that among all groups were significant
differences p<0.01 in ?e color changes means values when
compared before bleaching with 48 hours, 3months after
bleaching time follow up except ceram.x.mono was no
significant that means there was bleaching effect on these
materials, as seen in table (2) and diagrams(1, 2. 3). while
among all groups were no significant differences in ?e color
changes means values when compared before bleaching with
6months after bleaching time follow up except isp empress
direct was significant differences p<0.01 that means there
paper id: 02013454 78
international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
was time effect on these materials, as seen in table (2) and
diagrams(1, 2. 3).
within beautifil ii and isp empress direct composite resin
specimens’ discs, between before bleaching time follow up
and 48 hours after bleaching all-time follow up of the three
groups composite resin specimens discs. while only ?e for
48 hours after bleaching showed highly significant
differences in between groups that means there were
bleaching effect on these materials, as seen in table (2) and
diagrams(4).
3.1. the effects of bleaching on each composite resin
group’s specimens discs
3.1.1. the effects of bleaching on beautifil ii (b)
composite resin group’s specimens discs
tables 3, 4 and diagrams 2, 3, 4 were showed that:
1. results were showed highly significant differences
(p<0.01) of the beautifil ii discs’ specimens in the ?l*,
?a* ?b* and ?e means values (f=47.07, f=45.248,
f=28.02, f=398.7 respectively) for 6-months’ time follow
up that means there were an effect differences changes on
l* a* b* and ?e of these materials (table 3).
2. results showed that the l* and b* means values were
highly significant differences decrease (p<0.01) mean
values for before bleaching comparing with 48 after
bleaching, 3 months and 6 months after bleaching that
means bleaching had an effect on mean values of this
material. results showed of the l* and b* means values
of the beautifil ii discs’ specimens decrease for time
follow up: after 48 hours of bleaching, 3-months after
bleaching and 6-months after bleaching.
3. results showed that the a* mean values of the beautifil ii
discs’ specimens were highly significant differences
increase (p<0.01) mean values for before bleaching
comparing with 48 after bleaching, 3 months and 6
months after bleaching that means bleaching had an effect
on color changes (?e) values of this material. the a*
mean values change from negative to positive means
values that means specimens color were became redder in
color than for before bleaching time follow up.
4. results showed that the ?e means values were highly
significant differences decrease (p<0.01) mean values for
48 hours after bleaching comparing with 3 months and 6
months after bleaching that means bleaching had an effect
on mean values of this material. results showed of the ?e
means values of the beautifil ii discs’ specimens decrease
for time follow up: 3 months after bleaching and 6 months
after bleaching
3.1.2 the effects of bleaching on isp empress direct
discs’ specimens group (e)
tables 5, 6 and diagrams 2, 3, 4 were showed that:
1. results were showed significant differences in the ?l*,
?a* and ?e means values f=3.417 p=0.027, f=2.646
p=0.049, f=7.969 p=0.002 respectively, while b* showed
no significant differences (f=0.607 p=0.426) for 6
months’ time follow up (tables 5, 6).
2. results showed that the l* means values were not
significant among 6 months’ time follow up, except before
bleaching comparing with 48 after bleaching was
significant differences increase (p<0.01) that means
bleaching had an effect on mean values of this material for
that time follow up (positive increase direction in mean
value), and the specimens became lighter after. while
(positive decrease direction in mean value) and the
specimens became darker for 3-months and 6-months after
bleaching time follow up.
3. results showed that the a* means values was not
significant among all 6 months’ time follow up except
before bleaching comparing with 48 after bleaching was
significant differences increase (p<0.01) (negative
increase direction in mean value) that means the
specimens became greener in negative mean values and
bleaching had an effect on mean values of this material for
that time follow up.
4. results showed that the b* means values was not
significant among 6 months’ time follow up. (tables 5, 6).
5. results showed that the ?e means values was not
significant among 6 months’ time follow up except before
bleaching comparing with 3 months after bleaching was
significant differences increase (p<0.011) (tables 5, 6).
3.1.3. the effects of bleaching on ceram.x.mono discs’
specimens groups (c)
tables (7, 8) and diagrams (2, 3, 4) were showed that:
1. the ?l*, ?a*?b* and ?e were showed no significant
differences f=0.607 p=0.615, f=0.986 p=0.410, f=0.503
p=0.682 respectively except ?e means values was
significant differences f=8.843 p=0.001 in for 6 months’
time follow up.
2. results showed that the l**, ?a* and ?b* means values
were not significant among 6 months’ time follow up
that means bleaching had no or very little effect on these
means values of this material.
3. results showed that the ?e mean were significant
differences decrease (p=0.043) mean values for 48 hours
after bleaching comparing with 3 months after bleaching
and highly significant differences decrease (p<0.01)
comparing with 6 months after bleaching that means
bleaching had an effect on color changes (?e) values of
this material.
4. discussion
discoloration of resin composite remains a major cause for
the aesthetic failure of materials. such discoloration may be
caused by intrinsic and extrinsic factors. the intrinsic factors
involve the discoloration of the resin material itself. every
component of resin composite material may take part in this
phenomenon. to ensure excellent aesthetics, it is necessary
for tooth colored restorations to maintain intrinsic color
stability and resistance to surface staining. extrinsic factors
for discolorations are known to cause staining of composite
restorations. [28].
the results collected in the present investigation showed
these differences in color change might be related to
differences in chemical composition, size, distribution of
filler partials therefore a larger area of interface between
partial-matrix composite, possibly making it more
susceptible to discoloration. bleaching have an effect
increase means values of a* became redness and ?e color
while decrease in l* darker and b*became blueness of
beautify ii resin composite. and for isp empress direct
resin composite have an effect increase means values of l*
the brightness became lightness, b* chroma became
paper id: 02013454 79
international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
yellowness and ?e color while decrease in a* became
greenness.
finally bleaching have an effect increase means values of l
became lighter * and ?e color while decrease in a* became
greener and b* became blueness of ceram.x.mono resin
composite. despite increase in brightness that was evident
for these composites, this parameter alone was not
conclusive or decisive for description of color, since color
can only be described in three dimensions. this statement is
corroborated by lim et al. [29] who concluded that the
correlation between the contents of cargo, chroma and value
is moderate, despite a direct relationship between content
loading, scattering coefficient and reflected light. the
increase in mean ?e values for all groups and showed a
decrease in mean ?e values during 6 months following
bleaching this was supported by other studies. [30], [31],
[32] and [33].
this in vitro study has several limitations. one is the lack of
thermo cycling that could influence the degree of total color
change. specimens in the present investigation were not
thermally cycled. thermal cycling is an important factor that
affected the color of resin composite restorations. thermo
cycling is an in vitro process for which the tested materials
were subjected to large temperature extremes compatible
with the oral cavity. the difference in thermal expansion
coefficient or thermal conductivity coefficient between filler
particles and resin matrix may result in a difference in
thermal volumetric changes between resin matrix and filler
particles. furthermore, it must be mentioned that hydrolytic
degradation of bonding between resin matrix and filler
particles also occurred during thermal cycling as result of
water absorption. it was also reported that water absorption
would be accompanied by hygroscopic expansion in the
resin matrix and filler phase, thereby enhancing the
weakening filler–matrix interface. all these factors led to the
dislodgement of filler particles and effect on color changes
therefore should be considered in future research.
5. conclusions
based on the results obtained from this investigation, the
following conclusions could be derived:
1.bleaching have an effect increase means values of a* and
?e color while decrease in l*and b* of beautifil ii resin
composite.
2. bleaching have an effect increase means values of l*, b*
and ?e color while decrease in a* of imp empress direct
resin composite.
3. bleaching have an effect increase means values of l* and
?e color while decrease in a*and b* of ceram.x.mono
resin composite.
4. all parameter there were decrease in mean value with
time follow up.
5. future scope of this study to the use of in-office
bleaching gel have enhance esthetic apparent effect on
beautiful restoration and to use (surface pre-reacted glass
ionomer) technology that contains a stable phase of glassionomer
for aesthetic and long-lasting restorations that
release and recharge fluoride on other types composite
resin to improve chemicals and physicals properties.
table 1: groups’ specimen’s distribution for time follows up
testing
discs groups time follow up testing.
before
bleaching
after 48
hours.
after 3
months.
after 6 months
bleaching
beautifil ii composite
(group one, n=40)
10 discs 10 discs 10
discs
10 discs
ips empress direct
composite (group
two, n=40)
10 discs 10 discs 10
discs
10 discs
ceram-x.mono
composite (group
three, n=40)
10 discs 10 discs 10
discs
10 discs
table 2: one-way anova test for the cie l* a* b* color
system and ?e, among the three groups composite resin
specimens discs for 6-months’ time follow up.
before
bleaching
after 48
hours of
bleaching
3-months
after
bleaching
6-months
after
bleaching
groups
b&
e&
c
l* f-test 151.6 151.06 37.37 59.44
p-value
p<0.01 p<0.01 p<0.01 p<0.01
hs hs hs hs
a* f-test 622.07 370.7 318.4 410.4
p-value
p<0.01 p<0.01 p<0.01 p<0.01
hs hs hs hs
b* f-test 788.9 247.3 111.6 118.5
p-value
p<0.01 p<0.01 p<0.01 p<0.01
hs hs hs hs
between
groups
b&e&c
f-test ?e 337.7 0.139 1.017
p-value ?e p<0.01 0.871 0.375
hs ns ns
b: beautiful ii group, e: isp empress direct group, c:
ceram.x.mono group.
table 3: descriptive statistics of ?l*, ?a* and ?b* values
of beautifil ii discs’ specimens (b) for 6-months, subgroups
(n=10).
before
bleaching
48 hours
after
bleaching
3-months
after
bleaching
6-months
after
bleaching
ftest
pvalue
b l* mean 83.15 80.07 80.7 80.49 47.07 p<0.0
sd 0.508 0.0483046 0.775 0.884 1 hs
a* mean -0.37 0.87 0.62 0.55 45.248 p<0.0
sd 0.17 0.0483046 0.362 0.314 1 hs
b* mean 20.57 15.06 15.22 15.16 28.02 p<0.0
sd 0.236 0.052 0.155 0.151 1 hs
?e
b
mean 6.452 0.725 0.277 398.7 p?0.0
sd 0.306 0.843 0.297 1 hs
b: beautiful ii group, e: isp empress direct group, c:
ceram.x.mono group.
*same latter in same row significant differences,*different
number in same colom significant differences.
paper id: 02013454 80
international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
table 4: lsd multiple comparisons in the cie l* a* b*
color in beautifil ii discs’ specimens group (b), base line
measurements for all 6-months’ time follow up (n=10).
before
bleaching&
48 hours after
bleaching
before
bleaching& 3
months after
bleaching
before
bleaching& 6
months after
bleaching
b l* p-value p<0.01 p<0.01 p<0.01
sig hs hs hs
a* p-value p<0.01 p<0.01 p<0.01
sig hs hs hs
b* p-value p<0.01 p<0.01 p<0.01
sig hs hs hs
?eb 48 hours after
bleaching&3
months after
bleaching
48 hours after
bleaching&6
months after
bleaching
p-value p<0.01 p<0.01
sig hs hs
b: beautiful ii group, e: isp empress direct group, c:
ceram.x.mono group.
table 5: descriptive statistics of ?l*, ?a*, ?b* and ?e
values of isp empress direct discs’ specimens group (e) for
all time intervals subgroups (n=10).
before
bleaching
48 hours
after
bleaching
3 months
after
bleaching
6 months
after
bleaching
f-test pvalue
e l* mean 79.08 79.46 78.9 78.01 3.417 0.027
sd 0.397 0.381 0.483 0.396 s
a*mean -2.26 -2.46 -2.18 -2.28 2.646 0.049
sd 0.201 0.143 0.282 0.266 s
b*mean 12.85 13.12 12.86 12.78 0.951 0.426
sd 0.525 0.301 0.538 0.531 ns
e mean ?e 0.177 0.248 0.748 7.969 0.002
sd ?e 0.072 0.207 0.562 s
b: beautiful ii group, e: isp empress direct group, c:
table 6: lsd multiple comparisons in the cie l* a* b* and
?e color in isp empress direct discs’ specimens (e) group
among before bleaching measurements other time intervals
periods (n=10).
before
bleaching& 48
hours after
bleaching
before
bleaching& 3
months after
bleaching
before
bleaching& 6
months after
bleaching
e l* p-value 0.048 0.340 0.709
sig s ns ns
a* p-value 0.049 0.441 0.847
sig s ns ns
b* p-value 0.221 0.963 0.748
sig ns ns ns
e p-value ?e 0.654 0.001
sig ?e ns s
b: beautiful ii group, e: isp empress direct group, c:
ceram.x.mono group.
table 7: descriptive statistics of ?l*, ?a*, ?b* and ?e
values of ceram.x.mono discs’ specimens group (c) and for
all time intervals subgroups (n=10).
before
bleaching
after 48
hours of
bleaching
three
months
six
months
later
f-test p-value
ceram.x.mono
l* mean 82.51 82.77 82.52 82.35 0.607 0.615
sd 0.729 0.685 0.712 0.69 ns
a* mean 0.3 0.26 0.24 0.24 0.986 0.41
sd 0.125 0.052 0.084 0.084 ns
b* mean 15.5 15.3 15.31 15.31 0.503 0.682
sd 0.503 0.283 0.453 0.453
c mean ?e 0.17 0.859 0.995 7.439 0.003s
sd ?e 0.106 0.608 0.639
diagram 1: l* color space for all groups for 6-months
intervals
diagram 2: a* color space for all groups for 6-months
intervals.
color spaces for all group
diagram 3: b* color space for all groups for 6-months
intervals.
paper id: 02013454 81
international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
diagram 4: color change for all composite resin groups’
specimen’s discs for 6-months’ time follow up
references
[1] g. kugel and s. kastali, “tooth whitening efficacy and
safety: a randomized and controlled clinical
trial,”compend contin educ dent, vol. 29, pp516–521,
2000.
[2] j.e. dahl, “tooth bleaching – a critical review of the
biological aspects,” critic rev oral bio med, vol. 14,
pp292–304, 2003.
[3] t. attin, c. hannig, a. wiegand, r. attin., “effect of
bleaching on restorative materials and composite resin
s-a systematic review”, dental materials, vol.20,
pp852–61, 2004.
[4] s. canay and m. cehreli., “the effect of current
bleaching agents on the color of light-polymerized
composites in vitro”, journal of prosthetic dentistry,
vol. 89, pp474–8, 2003.
[5] p. villalta, h. lu, z. okte, f. garcia-godoy, j. powers.,
“effects of staining and bleaching on color change of
dental composite resins”, journal of prosthetic
dentistry, vol. 95, pp137–42, 2006.
[6] jh. kim, yk. lee, bs. lim, sh. rhee, hc. yang.
“effect of tooth whitening strips and films on changes in
color and surface roughness of resin composites”,
clinical oral investigations, vol. 8, pp118–22, 2004.
[7] p. monaghan, e. lim, e. lautenschlager., “effects of
home bleaching preparations on composite resin color”,
journal of prosthetic dentistry, vol. 68, pp575–7, 1992.
[8] f. yalcin and s.gurgan., “bleaching-induced color
change in plastic filling materials”, journal of
biomaterials applications, vol.19, pp187–195, 2005.
[9] f. yalcin and s. gurgan., “effect of two different
bleaching regimens on the gloss of tooth colored
restorative materials”, dental materials, vol.21, pp464–
468, 2005.
[10]rm. fay, t. servos, jm.powers. “color of restorative
materials after staining and bleaching”, operative
dentistry, vol. 24, pp292–296, 1999.
[11]sb.turker, t.biskin, “effect of three bleaching agents
on the surface properties of three different esthetic
restorative materials”, journal of prosthetic dentistry,
vol. 89, pp466–73, 2003.
[12]e.assmussen, “softening of bis-gma polymers by
ethanol and organic acids of plaque,” scand j dent res,
vol. 92, pp.257–261, 1984.
[13]e.assmussen, “factors affecting the quantity of
remaining double bonds in restorative resin polymers,”
scand j dent res, vol. 90, pp.490–496, 1982.
[14]w. wu, j.e. mckinney, “influence of chemicals on
wear of dental composites,” j dent res, vol.61,
pp.1180–1183, 1982.
[15] n. abu-bakr, l. han, a. okamoto, m.iwaku, “color
stability of compomers after immersion in various
media,” j esthet dent,vol. 12,pp.258–266,2000.
[16]b.a matis, m.youset, m.a. cochram and g.j. eckert,
“degradation of bleaching gels in vivo as a function of
tray design and carbamide peroxide concentration, ” per
dent, vol.27, pp.12–18, 2002.
[17]v.b. haywood, h.o. heymann. “nightguard vital
bleaching,” quint int,vol. 20,pp.173–176,1989.
[18] l. greenwall, “bleaching techniques in restorative
dentistry,” an illustrated guide. martin duntz ltd
united kingdom, 2001.
[19] k.a. schulze, s.j. marshall, s.a. gansky, g.w.
marshall. “color stability and hardness in dental
composites after accelerated aging,” dent mater,
vol.19, pp.612–619, 2003.
[20]r. janda, j.f. roulet, m. kaminsky, g. steffin,
m.latta, “color stability of resin matrix restorative
materials as a function of methods of light activation, ”
eur j oral sci, vol.112, pp.280–285, 2004.
[21] e. ertas, a.u. güler, a.c. yücel, e.güler, “color
stability of resin composite after immersion in different
drinks,” dent mater j., vol. 25, pp.371–376, 2006.
[22]goldstein re,garber da. complete dental bleaching.
1st ed. quintessence: chicago 1995. p25-33.
[23]lima da, aguiar fh, liporoni pc, munin e,
ambrosano gm, lovadino jr. in vitro evaluation of the
effectiveness of bleaching agents activated by different
light sources. j prosthodont 2009 18: 249-254.
[24] vijay mathai, mano c angelo, k. mariamma , k.
jayakumar, k. sarath babu, “comparative
evaluation of the effect of 15%
carbamide peroxide bleaching on shear
bond strength using three different
adhesive systems: an invitro study, ”
international journal of analytical, pharmaceutical
and biomedical sciences., vol. 2, (1), pp. 18-23, jan-
mar-2013.
[25]maria beatriz freitas d’arce, débora alves nunes
leite lima, fl?vio henrique baggio aguiar, carlos
eduardo dos santos bertoldo, gl?ucia maria bovi
ambrosano, josé roberto lovadino, “effectiveness of
dental bleaching in depth after using different bleaching
agents”, j clin exp dent.,vol.5, (2), pp.100-7, 2013.
[26] i.e. ruyter, k. nimler, b. moller, “color stability of
dental composite resin materials for crown and bridge
veneers, ” dent mater,vol. 3, pp.246–251, 1987.
[27]w.m. johnston, e.c. kao, “assessment of appearance
match by visual observation and clinical colorimetry,” j
dent res.vol. 68, pp.819–822, 1989.
[28]suemori t, kato j, nakazawa t, akashi g, igarashi a,
hirai y, kumagai y, kurata h. effects of light
irradiation on bleaching by a 3.5% hydrogen peroxide
solution containing titanium dioxide. laser phys 2008
5: 379-383.
paper id: 02013454 82
international journal of science and research (ijsr)
issn (online): 2319-7064
volume 3 issue 1, january 2014
www.ijsr.net
[29]lim yk, lee yk, lim bs, rhee sh, yang hc.
influence of filler distribution on the color parameters
of experimental resin composites. dent mater
2008 24:67-73.
[30]d. hufschmidt, d. bahnemann, j. j. testab, c.a.
emilio and m. i. litter,enhancement of the
photocatalytic activity of various tio2 materials by
platinwasation, journal of photochemwastry and
photobiology a: chemwastry 148 (2002) 223-231.
[31]v.m. menéndez-flores, d. friedmann, and d. w.
bahnemann,durability of ag-tio2)(photocatalysts
assessed for the degradation of dichloroacetic acid,
international journal of photoenergy (2008) article id
280513, 11 pages, 2008. doi:10.1155/2008/280513.
[32] a.a. wasmail, d.w.bahnemann, l. robben,
v.yarovyi, and m. wark, palladium doped porous
titania photo catalysts: impact of mesoporous order and
crystallinity, chemwastry of materials 22 (2010) 108–
116.
[33]ayad f. alkaim, and mohammed b.
alqaraguly,adsorption and photocatalytic degradation
of crystal violet dye in the presence of different metals
doping on tio2, journal of applicable chemwastry 2
(2013) 291-303.
author profile
ameer al-ameedee received the b.s. and m.s.
degrees in dentistry from college of dentistry
/baghdad university 1985 and 2005, respectively.
during 1985-1996, he studied high dental diploma
(hdd. practical and scientific experience):
1-training course in prosthetic baghdad 1986.
2-training course in computer science/ babylon university /1996.
3-training course in dental implant-ology conference baghdad
1998.
4- training course endodontic conference baghdad 2004
5- in candidate of ph.d. conservative dentistry - from 2010 - to
date.
paper id: 02013454 83