Received: 16 March 2017
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Revised: 18 April 2017
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Accepted: 25 April 2017
DOI: 10.1111/jerd.12308
RESEARCH ARTICLE
Effect of resin infiltration on the color and microhardness of bleached white-spot lesions in bovine enamel (an in vitro study) Sidika Aynur Horuztepe, DDS, PhD1 1 DDS, PHD, Specialist in Restorative Dentistry at EOTDental Clinic, Ankara, Turkey
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Meserret Baseren, DDS, PhD2
Abstract Objectives: The aim of this study was to investigate both the effect of resin infiltration on the
2
DDS, PHD, professor, Department of Restorative Dentistry, Hacettepe University, Ankara, Turkey Correspondence Sidika Aynur Horuztepe, Specialist in Restorative Dentistry at EOT Dental Clinic, 06680 Cankaya, Ankara, Turkey. Email:
[email protected]
color and microhardness of white spot lesions (WSLs) that treated with bleaching and to analyze the penetration of the infiltrant. Materials and Methods: In each of 135 bovine enamel specimens, WSLs were produced. The samples were then randomly divided into three groups (n 5 45): group I, bleached; group II, resininfiltrated; group III, bleached and resin-infiltrated. The specimens were subjected to a pH-cycling regime for four weeks. The color and microhardness were measured at the baseline, after production of WSLs, after the treatments. The color alteration (DE*) and the percentage of surface microhardness recovery (SMHR) were calculated. The penetration of the infiltrant was evaluated by scanning electron microscopy. Results were analyzed with analysis of variance, Shapiro–Wilk, Tukey’s, Kruskal–Wallis and Conover–Dunn tests (P 5 .05). Results: The SMHR% in resin infiltration groups was significantly higher than that of the bleached group only (P < .05). Bleaching treatment prior to resin infiltration produced no significant change in the microhardness (P > .05). Using a bleaching treatment prior to resin infiltration produced significant color alteration (P < .05). The penetration of the resin infiltrant was deepest in-group II. Conclusions: The resin infiltration enhanced the microhardness of the WSLs regardless of whether or not a bleaching treatment was used. Using a bleaching treatment before resin infiltration resulted in color alteration, and it was also found to negatively influence the penetration of the infiltrant. KEYWORDS
resin infiltration, tooth bleaching, white spot lesion
impair the esthetic outcome of any such treatment.4 In some cases,
1 | INTRODUCTION
WSLs may remineralize and return to a visually acceptable appearance White spot lesions (WSLs) are the first signs of incipient enamel caries,
within a year after debonding, because of the abrasive effect of tooth
and they are characterized by a loss of minerals under an intact surface
brushing. In some cases, however, WSLs may remain at an esthetically
1–4
layer and a whitish appearance.
WSLs are considered to be a com5–7
mon complication of fixed orthodontic treatments,
which might
unacceptable level.8,9 Several techniques have been proposed to camouflage white-spot lesions; the usual treatment chosen for WSLs consist of improving remi-
The manuscript was originally presented as an oral presentation at the International Association for Dental Research Continental European Division organizes its 47th Meeting of CED-IADR from 15 to 17 October, 2015, in Antalya, Turkey. Hacettepe University Research Fund, Grant/Award Number: 012. D06.201.003.
J Esthet Restor Dent. 2017;1–9.
neralization through CPP-ACP (Casein Phosphopeptide—Amorphous Calcium Phosphate) or fluoride-containing products, restorative procedures, microabrasion or through the use of a laser.4 Most of these techniques are effective for shallow WSLs, which require a lot clinical effort and removal of remineralizable enamel.3 Excellent esthetic results have
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C 2017 Wiley Periodicals, Inc. V
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been achieved using restorative techniques using composite and ceramic 10
materials,
but they are usually associated with an excessive loss in
sound dental hard tissue. Due to the reversible nature of white spots, 3
less invasive methods are generally preferred.
Recently, resin infiltration has been proposed as an alternative minimally invasive treatment option for enamel WSLs; it was originally developed to prevent proximal caries lesions.11,12 It is a promising therapeutic technique, as it makes use of both preventive and restorative actions in the treatment of noncavitated carious lesions.13 After the removal of the hypermineralized surface layer, the penetration of the low-viscosity resin (i.e., an infiltrant) into the lesion depth is driven by capillary forces.3,12 Thus, the progression of lesion is slowed down, and
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2.1 | Sample preparation Enamel–dentin specimens (5 mm 3 4 mm, 1 mm enamel and 1 mm dentin thickness) were prepared from bovine incisors, with the second dentition used (n 5 135). After being embedded in an acrylic resin, the enamel surfaces polished using 1200, 2400, 4000 grit silicone carbide paper respectively. All of the surfaces of the samples were examined using a stereomicroscope to ensure that there were no cracks or other surface defects. After preparation, the specimens were stored in deionized water at 48C to prevent dehydration from occurring.
2.2 | Color measurement
even stopped, by occluding the porosities that increase the diffusion of
After the samples had been carefully dried with absorbent paper, meas-
acids.13 This not only reduces the microporosities, but also provides
urements were made of the baseline color from the enamel surface of
12,13
In addition to controlling
the specimens; these were done under standardized ambient condi-
lesion progression, the resin infiltration of WSLs produces a positive
tions using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik,
some mechanical support to the tissue.
side-effect, as it masks the whitish appearance of enamel, as a resin 5
Bad Säckingen, Germany) that recorded color variables L*, a*, and b*
with a refractive index similar to that of healthy teeth is used. Resin
according to the Commission Internationale de l’Eclairage (CIE), these
infiltration has been proven to be effective both in situ14 and in
three variables represent a tri-dimensional color space that has three
vivo.15,16 When WSLs are masked by the resin infiltration technique,
axes: the L* axis represents the degree of lightness within a sample,
the chalky white appearance is removed, and the area is restored to
and it ranges from 0 (black) to 100 (white); the a* axis is a parameter in
the enamel’s original color. However, resin infiltration may make teeth
the red–green direction; whereas the b* axis is a parameter in
looker darker, as patients can become accustomed to the white opaque
the blue–yellow direction.17 The spectrophotometer made three
appearance of WSLs;17 in such cases, a bleaching treatment can be
consecutive readings, automatically calculating the mean values of L*,
performed before the resin infiltration.
a*, and b*.
Treatments that whiten discolored teeth have become popular in
The color measurements were conducted at the baseline, after
recent years, as they are an easy, inexpensive, and conservative
WSLs were formed, and after pH cycles had been conducted over 28
method for improving the color of such teeth. Bleaching is also consid-
days. The L*, a*, and b* values were recorded for each measurement,
ered to be a simple and effective procedure for removing internal and
and the values of the changes in L* (DL), a* (Da), and b* (Db) were calcu-
external discolorations from teeth.18 Tooth whitening has also been recommended as a way to camouflage the appearance of WSLs, as it can reduce the contrast between these lesions and the enamel adjacent to it.19 However, it is currently unclear whether bleaching agents
lated. The total color change (DE) of each tooth was calculated according to the following formula: h i1⁄2 DE 5 ðDLÞ2 1 ðDaÞ2 1 ðDbÞ2
have a negative impact on WSLs.20 Although a recent study evaluated the effect of bleaching on resin-infiltrated demineralized lesions,17 no information is available on how bleaching affects demineralized enamel before resin infiltration occurs. The aim of this in vitro study, therefore is to investigate the effect of bleaching treatments on the microhardness and color of WSLs before resin infiltration is carried out. The first hypothesis we tested was that the microhardness of WSLs would decrease after bleaching. The second hypothesis was that the resin infiltrant would increase the microhardness of negatively affected bleached WSLs. The third, meanwhile, was that bleaching treatments carry out before resin infiltration would cause a clinically
2.3 | Microhardness measurement Surface microhardness (SMH) measurements were conducted at the baseline condition, after WSLs were formed, and after pH cycles had been conducted over 28 days. Vicker’s hardness number (VHN) of each enamel surface in a sample was measured with a microindentation hardness tester (Shimadzu HMV-2, Tokyo, Japan) that was fitted with a 50-g load for 15 seconds. Three indentations, 100 mm apart, were made at the center of each specimen before being averaged. The mean VHN and percentage of surface microhardness recovery value (SMHR%) of each specimen were also calculated.
significant change in the color of WSLs.
2.4 | Formation of white spot lesions To visualize the formation of the WSLs, half of the enamel surface of
2 | MATERIALS AND METHODS
each specimen was covered with acid-resistant nail varnish (Rossmann, Burgwedel, Germany), although the other half was left unprotected.
The experimental flow diagram is presented in Figure 1.
Artificial WSLs in the unprotected areas were created by storing the
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FIGURE 1
Flow diagram of the experimental procedure
3
specimens in 5 L of a demineralizing solution containing 50 mM acetic
mens were then washed using a soft brush for 1 minutes and then
acid, 3 mM CaCl212H2O, 3 mM KH2PO4,
50 mM
stored in distilled water at room temperature during the intervals
KOH, 6 mM thymol, H2O, and 10 mM methylhydroxy-diphosphonate
between the treatment phases. At the end of the treatment, they were
(pH 4.95; 37.88C) for 28 days.21 The pH level was monitored daily and,
pH-cycled for 28 days.
3 mM
CH3COOH,
if necessary, adjusted with either hydrochloric acid (10%) or a potassium hydroxide solution (10 M). The specimens were randomly divided into three groups according to the experimental protocols (n 5 45):
2.4.2 | Group II (resin-infiltrated WSL) The specimens were submitted to resin infiltration as per to the manufacturer’s instructions. Hydrochloric acid gel (15%) (Icon-Etch, DMG, Hamburg, Germany) was applied to the surface of a WSL for 2 minutes,
2.4.1 | Group I (bleached WSL)
and then it was rinsed with water and dried in air for 30 seconds
The WSLs were treated with a chemically activated office-bleaching
before ethanol (Icon-Dry, DMG, Hamburg, Germany) was applied for
system (Opalescence Boost 40% Hydrogen Peroxide, Ultradent, South
30 seconds; the sample was then subsequently air dried some more. A
Jordan, UT, USA) as per the manufacturer’s instructions.
low-viscosity resin infiltrant (Icon-Infiltrant, DMG, Hamburg, Germany)
The bleaching system consisted of two syringes: one syringe con-
was then applied to the surface for 3 minutes and the sample was
tained the activator, whereas the other contained hydrogen peroxide.
light-cured for 40 seconds (Hilux Ledmax 5, Benlio glu Dental Inc,
Before being applied, the bleaching agent was mixed with the activator.
Ankara, Turkey). The resin infiltrant was reapplied for 1 minutes before
The activated gel was applied as a 0.5–1-mm-thick layer to the surfa-
the sample was again light-cured. The surface of the specimens was
ces of the teeth for 20 minutes through two applications. The speci-
polished using flexible discs (Sof-Lex, 3M ESPE, St Paul, MN, USA) for
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FIGURE 2
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SEM view of a section of the WSL at, (a) 1,000 times magnification, and (b) 5,000 times magnification
about 20 seconds to remove any excess resin. The specimens were then stored in distilled water at room temperature during the intervals between the treatment phases. After infiltration, the samples were pHcycled for 28 days.
2.6 | Scanning electron microscopic (SEM) analysis For the SEM analysis, five specimens of each group were randomly selected. After they were horizontally cross-sectioned along the midline, the exposed surfaces were polished using 1200, 2400, and 4000 grit abrasive papers respectively. The polished specimens were then
2.4.3 | Group III (bleached/resin infiltrated WSL) The specimens were bleach treated, as they were for group I. After they were pH-cycled for 14 days, the resin infiltrant was applied to the bleached specimens, as in group I. They were then pH-cycled for a further 14 days after infiltration.
put into an ultrasonic bath (Amsco, Reliance Sonic 250, Steris Corp., Mentor, OH, USA) in deionized water for 10 minutes, before being immersed in 95% ethanol and dried for 72 hours in a desiccator. The test specimens were fixed to metal stubs by doubled-faced carbon tape and sputter-coated with gold–palladium using a vacuum metalizing appliance; they were then examined under a scanning electron microscope (Carl Zeiss EVO-50 EP, Cambridge, UK) at 20 kV to evaluate the penetration depth of the resin infiltrant. The samples were pho-
2.5 | pH cycling
tographed using magnifications of 500, 1000, and 5000 times
All of the specimens were subjected for 28 days to a pH-cycling regi-
magnifications.
men to simulate oral conditions, as described by White.22 Artificial saliva composed of 1.5 mM CaCl2, 0.9 mM KH2PO4, 130 mM KCl,
2.7 | Statistical analysis
1 mM NaN3, and 20 mmol/L HEPES was used as a remineralizing solu-
Statistical analyzes were performed with SPSS (Statistics 20.0 for Win-
tion (pH 7.0) as described by ten Cate and Duijsters.23 The pH cycling
dows, IBM SPSS, Armonk, NY, USA). The distributions of the color
consisted of exposing the samples to acidic challenge in the deminerali-
(DE*, L*, a*, b*) and hardness (SMH, SMHR) values were investigated
zation solution from 11:00 am to 1:00 pm on a daily basis, and they
using the Shapiro–Wilk test. For the normal distribution groups and
were placed in remineralizing solution for the rest of the day (approx.
sub-groups, a variance analysis (ANOVA), a Tukey’s test, and repeated
22 hours/day). The specimens were washed with deionized water
measures ANOVA (rANOVA) were used; for the non-normal distribu-
when from one immersion to the other. Solution treatment was carry
tion groups and subgroups, the Kruskal–Wallis and Conover–Dunn
out at 378C.22
tests were used (P 5 .05).
TA BL E 1
Surface microhardness and surface microhardness recovery of all groups (mean 6 SD, n 5 45)
Groups
Baseline SMH
After WSL formation SMH
After experimental protocols SMH
SMHR%
Bleached WSL (Group I)
203.64 6 30.91aA
109.46 6 23.81aB
132.96 6 31.73aC
30.67 6 31.73a
Resin infiltrated WSL (Group II)
198.09 6 26.94aA
109.53 6 21.7aB
212.82 6 27.49bA
131.69 6 59.07b
Bleached/Resin infiltrated WSL (Group III)
196.9 6 33.65aA
104.89 6 21.29aB
207.31 6 32.28bA
121.71 6 65.13b
Different uppercase letters in columns and lowercase letters in rows indicate statistically significant difference (Tukey’s test; P < .05).
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trant into the demineralized area can be observed in Figure 3b. The cross-sectional view of the infiltrated lesions showed that groups II and III had different morphologies (Figures 4 and 5). In the bleached/resin-infiltrated group (group III), a distinct ultramorphologies like as holes and column gaps were observed amongst the cured resin material, which indicates that the mineral phase fluorapatite was unable to be infiltrated completely by the resin (Figure 4b). A better penetration into the demineralized enamel was achieved by applying
0.001 0.001 0.878 0.001 0.001 0.02 0.736 0.268 0.51 0.865 0.773
5.6 6.79 5.05 2.96 0.89 2.69 2.68 2.22 7.81 4.72 10.09 SD
3.63
21.49 23.80 10.74 21.35 0.17 86.67 38.25 6.64 77.06 41.24
6.22 7.73 4.63 4.03 1.94 3.81 4.22 1.98 7.31 3.98 3.87
12.60 16.18 11.17 31.7 1.66 84.75 38.64 6.02 78.72
4.82 6.39 6.25 2.64 1.51 3.58 3.48
17.78 10.62
White spot lesion formation vs experimental applications DE b*
26.59 2.25 85.11 38.07 6.1
1.61 6.82 4.04
41.32 5.01
5.12 79.09
0.548 P value
exposed the underlying structures. The penetration of the resin infil-
Mean
resulted in the complete dissolution of the surface layer, which
Bleached/Resin Infiltrated WSL (Group III)
Figure 3a shows the removal of the surface layer by HCl acid. The etching protocol for the infiltrant (15% HCl gel for 120 seconds)
12.04
was observed on the surface of the mineral column.
SD
rated with gaps extending all the way to the lesion. Crystal dissolution
81.07
2a. Figure 2b shows that the longitudinal mineral columns were sepa-
Mean
An intact sound enamel layer can be observed over the WSL in Figure
Resin Infiltrated WSL (Group II)
3.3 | SEM evaluation
2.94
ences in the DE* values (P > .05) of the two.
9.98
between groups I and II indicated that there were no significant differ-
SD
duced a significant color alteration in WSLs. However, a comparison
78.49
other words, using a bleaching treatment prior to resin infiltration pro-
40.86
groups in terms of DE (Table 2). The Tukey’s test revealed that the group III samples exhibited had the highest color alteration (P < .05); in
4.62
tocols was visually detectable (DE > 3.2). According to the one-way ANOVA test, significant differences were observed between the three
78.76
improvement in the color of the WSLs following the experimental pro-
Mean
experimental protocols along with the color alteration values (DE). The
Bleached WSL (Group I)
Table 2 presents the mean values of the CIE L*, a*, and b* values of the baseline condition, after the WSLs had been formed, and after the
a*
3.2 | Color evaluation
L*
ment groups (P < .05), whereas there was no significant difference between groups II and III (P > .05).
b*
Group I showed significantly lower SMHR% than the other two treat-
a*
The SMHR% values of all of the groups are shown in Table 1.
L*
ence in terms of microhardness (P > .05).
b*
prior to the resin infiltration was found to cause no significant differ-
a*
increase in the microhardness of WSLs (P < .05). Bleaching treatment
L*
Regardless of the bleaching treatment, the resin infiltration caused an
Groups n: 45
significantly different from that of the other tested groups (P < .05).
After the experimental applications
(P > .05), the lowest SMH value was observed in group I, which was
After white spot lesion formation
Although there were no statistically significant differences between groups II and III in terms of surface microhardness (SMH)
Baseline vs experimental applications DE
tocols are shown in Figure 2.
Color alteration DE
condition, after the WSLs were formed, and after the experimental pro-
CIE L*a*b* Mean color value
The surface microhardness values of the specimens at the baseline
T A B LE 2
3.1 | Microhardness evaluation
Mean values and standard deviations of CIE L*a*b* and, DE for intervals of after WSL formation and baseline, experimental applications and baseline and, experimental applications and WSL formation
3 | RESULTS
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Baseline
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Baseline vs white spot lesion formation DE
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F I G U R E 3 (a) SEM view of the eroded area in the demineralized enamel after etching for 120 s with HCl acid gel showing the dissolution of the enamel surface layer and the expose of the underlying layer (red arrows) (as viewed at 1,000 times magnification). (b) SEM view showing the penetration of the resin infiltrant into the spaces formed in the HCL acid-applied demineralized enamel seen in Fig.3a (red arrows) (as viewed at 1,000 times magnification)
only the resin infiltrant (group II) than by conducting the infiltration
enamel microhardness from being reduced to baseline values, and
after bleaching (group III).
these treatments made the teeth more resistant to higher caries than nonfluoridated bleaching treatments.24 Attin et al. reported that the
4 | DISCUSSION
use of fluoridated bleaching gels reversed the loss of enamel surfaces in a shorter amount of time than nonfluoridated gels did.25
In the present study, bovine teeth were used and caries-like artificial
Resin infiltration is a treatment option developed to prevent the
11,14
demineralization lesions were created, as in previous in vitro study.
progression of WSLs, and it is argued that the microhardness of porous
However, the difference between artificial demineralization lesions of
lesion bodies is increased when they are filled with a resin than when
bovine enamel and natural caries lesions of human might be a limitation
they are simply untreated or remineralized carious lesions.26 In the
to reflect the clinical conditions.
present study, regardless of bleaching, the resin-infiltrated groups
In our in vitro study, the effect of resin infiltration on the micro-
showed higher microhardness values. This reflects the ability of the
hardness and color change of bleached and unbleached WSLs was
low-viscosity resin to fill the spaces between the remaining crystals of
evaluated. As all of the treatments tested increased the microhardness
the porous lesions and re-harden the demineralized tissue, thereby
of the WSLs, the first hypothesis was rejected. The increased hardness
improving their mechanical strength.
values of the WSLs subjected to a bleaching agent (group I) could be
Similar results were also observed in a study conducted by Paris
related to the fluoride content of the bleaching agent used, as the
et al. In their study, they evaluated both resistance to demineralization
microhardness of the bleached WSLs was higher than that of the base-
and microhardness of infiltrated artificial enamel lesions with various
line values. These results are consistent with previous studies, which
experimental resin infiltrants; they found that the infiltrated lesions
found that bleaching treatments with fluoridation prevented the
were more resistant to acid attacks than untreated lesions.27
F I G U R E 4 (a) SEM view of the cross-sections of the bleached/resin-infiltrated lesions showing reduced and irregular infiltration of the resin into the demineralized enamel (at viewed at 500 times magnification). (b) SEM view of the cross-sections of the bleached/resininfiltrated lesions revealed a distinct ultramorphologies like as holes and column gaps were observed amongst the cured resin material (red arrows) (at viewed at 5,000 times magnification)
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F I G U R E 5 (a) SEM view of the cross-sections of the infiltrated lesions only for resin infiltrant-treated group shows that the resin penetration was greater and more uniform (at viewed at 500 times magnification). (b) SEM view of the cross-sections of the infiltrated lesions only for resin infiltrant-treated group shows more regular penetration of resin infiltrant (at viewed at 5,000 times magnification)
Our results concur with a recent analysis that identified an
a greater color change (DE*) was observed in the group treated with a
increase in the hardness of artificial dental caries when resin infiltration
resin infiltrant after bleaching than for the other groups. The color
was applied.28
alteration of WSLs are similar to previous studies9,32,33 which showed
In our study, although the group of sample that were treated with
an increased DE* values in both bleaching and resin infiltration groups.
a resin infiltrant after bleaching exhibited lower microhardness values
The results of this study agree with those reported by Johnston
than the group to which only a resin infiltrant was applied, no statisti-
et al.,34 who argued that a color change in DE exceeding 3.7 units is
cally significant difference was found between them. This can be
clinically visible. The bleaching treatment was effective in producing
explained by the fluoride in the bleaching agent potentially causing a
significant color changes in the WSLs, can be seen in Table 2.
rapid mineral precipitation on the enamel surface and resulting in an
After the bleaching treatment, significantly increased lightness and
obturation of the surface enamel pores that communicate with the
a reduced chroma were observed; however, decreasing whiteness is
underlying demineralized lesion. This process might have further lim-
often observed in the postbleaching period. Therefore, it is argued that
ited the resin infiltration of the sub-surface demineralized enamel. The
the long-term results of bleaching cannot remain stable. The reduction
second hypothesis tested in this study that the microhardness of the
of the lightness in the first week after bleaching may be associated
negatively affected bleached WSLs would increase the resin infiltrant,
with rehydration, and a further color regression towards that of the
was accepted. In a study evaluating the effect of fluoride varnish on
baseline shades might occur.35 As such, the color differences between
the penetration of an adhesive resin, the failures that occurred were
the procedures and the baseline were measured four weeks afterwards
predominantly at the enamel/resin interface. This was attributed to flu-
in the present study.
oride accumulation, which in turn prevented the resin from penetrating 29
into the enamel.
A recent in vitro study demonstrated that significant changes were observed for the L* and b* value of artificially created WSLs, but only a
The effect of using a bleaching treatment after resin infiltration
minimal change was found for a* when compared to the baseline con-
jo et al. showed has also been investigated in previous studies.17,30 Arau
dition.36 These types of color changes were similar to those achieved
that WSLs that had been infiltrated with a resin infiltrant were found
by traditional teeth whitening products that contain peroxide.37 Such
to experience significant color alteration after they had been stained
results were also observed in the present study, as notable deviations
by solutions such as wine or coffee. They suggested that the bleaching
were only recorded for L* and b*.
of the specimens could help minimize the staining effect.30 Unlike the
In our study, we evaluated how the different treatments improved
previous in vitro study that investigated the bleaching treatment effect
the appearance of WSLs by investigating the change in their color com-
on WSLs treated with resin infiltration techniques,17 this study eval-
ponents (L*, a*, and b*). Based on the results that we obtained, we
uated the effect of resin infiltration technique after bleaching; to the
believed that using a resin infiltration after bleaching resulted in
best of our knowledge, as of yet there is no related study.
increased overall whitening than that achieved by the other groups.
We preferred to bleach the WSLs before using a resin infiltration,
Color alterations (DE*) were observed in all of the groups, with the
because these lesions are usually masked by a resin, and some patients
highest change occurring for group III. In terms of the color differences
may their teeth have darkened, since the whitish appearance of the
between all three of the groups, no statistically significant differences
WSLs disappears and the real color of the teeth returns. This may
were found in the DE* values of groups II and I. Using a bleaching treat-
encourage clinicians to use resin infiltration after bleaching therapy
ment prior to resin infiltration was found to result in a significant color
instead of bleaching resin-infiltrated WSLs.
alteration of the WSLs. The third hypothesis that the bleaching treatments
Previous studies have demonstrated that it is possible to mask enamel WSLs using resin infiltration is used.3,5,13,31 Based on this idea,
would cause a clinically significant change in the color of WSLs before the resin infiltration, is therefore also considered to have been correct.
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Color of artificially formed WSLs significantly improved after the bleaching treatment as the colorant was removed and the inherent darkness of the teeth reduced. Additionally, the color of the WSLs was significantly better after resin infiltration, because the infiltrated resin had a low refractive index that could block pores. Thus, the porosities in the WSLs were occluded, and diffusion of the pigments was reduced; this resulted in the re-coloring of the lesions being hampered. The color change was also clinically recognizable (DE* > 3.7) between the baseline condition and after resin infiltration.
5 | CONCLUSIONS Within the limitations of this study, the following conclusions may be drawn: Using a bleaching treatment before resin infiltration resulted in significant color alteration. Resin infiltration significantly increases the microhardness of bleached and unbleached WSLs. Bleaching treatments negatively influence the penetration of infiltrants.
DISCLOS URE AND ACKNOWLEDGEMENTS The authors of this article certify that they have no proprietary, financial, or other personal interest of any nature or kind in any product, service, and/or company that is presented in this article.
ACKNOWLEDG MENTS This study was supported by grant No. 012.D06.201.003 from the Hacettepe University Research Fund. We like to thanks Dr. Ruya Yazici and Dr. Sevil Gurgan for their valuable advice.
RE FE RE NCE S [1] Fejerskov ONB, Kidd E. Dental caries: the disease and its clinical management. 2nd ed. Copenhagen: Blackwell Munksgaard; 2003. [2] Kidd EA, Fejerskov O. What constitutes dental caries? Histopathology of carious enamel and dentin related to the action of cariogenic biofilms. J Dent Res. 2004;83: Spec No C:C35-C38. [3] Paris S, Schwendicke F, Keltsch J, et al. Masking of white spot lesions by resin infiltration in vitro. J Dent. 2013;41(Suppl5):e28–e34. [4] Jeong-Hye Son BH, Kim H-C, Park J-K. Management of white spots: resin infiltration technique and microabrasion. J Korean Acad Conserv Dent. 2011;36(1):66–71. [5] Paris S, Meyer-Lueckel H. Masking of labial enamel white spot lesions by resin infiltration—a clinical report. Quintessence Int. 2009; 40(9):713–718. [6] Hadler-Olsen S, Sandvik K, El-Agroudi MA, Ogaard B. The incidence of caries and white spot lesions in orthodontically treated adolescents with a comprehensive caries prophylactic regimen–a prospective study. Eur J Orthod. 2012;34(5):633–639. [7] Boersma JG, van der Veen MH, Lagerweij MD, et al. Caries prevalence measured with QLF after treatment with fixed orthodontic appliances: influencing factors. Caries Res. 2005;39(1):41–47.
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How to cite this article: Horuztepe SA, Baseren M. Effect of resin infiltration on the color and microhardness of bleached white-spot lesions in bovine enamel (an in vitro study). J Esthet Restor Dent. 2017;00:000–000. https://doi.org/10.1111/jerd. 12308
