مجال
التميز
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تميز دراسي وبحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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Sagittal Condylar Angle and Gender Differences
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رابط إلى البحث:
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Click here
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تاريخ النشر:
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01-04-2013
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موجز عن البحث:
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Purpose:
The purpose of this study was to
measure sagittal condylar inclination (SCI) in male and female participants
and to assess differences between the two groups. This measurement has a
clinical value in setting the articulator SCI before fabrication of indirect
restorations.
Materials and
Methods:
The study included 32 dental students,
16 men and 16 women (aged 18 to 40 years). The participants had no signs of
muscular or articular pain. SCI was recorded for participants using a CADIAX®
compact 2 electronic axiograph.
Results:
The mean SCI in
both men and women varied between 26.1° and 61.8°, with a mean of 41.9° (SD
7.8). The mean right SCI was 42.0° (SD 8.5), and the mean left SCI was 41.9°
(SD 9.2). The mean SCI for men was 40.3° (SD 7.9), and the mean for women was
43.6° (SD 7.7). No statistically significant difference in SCI values was
found between the right and left side (p = 0.995),
or between the male and female groups (p = 0.133).
Also, no correlation could be found between SCI and the age of the
participants (r2 = 0.016, p = 0.489).
Conclusions:
The mean value of
SCI was within the range reported in previous studies. SCI is highly
variable, but this variability does not seem to be attributed to condylar
asymmetry, gender, or age of the adult participants. This high variability
suggests that independent condylar measurements should be conducted for each
patient instead of relying on reported average values.
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البحث ( 2):
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عنوان البحث:
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Degree
of conversion of bulk-fill compared to conventional resin-composites at two
time intervals
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رابط إلى البحث:
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تاريخ النشر:
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08-07-2013
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موجز عن البحث:
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Objective:
The purpose of
this study was to assess the degree of conversion (DC) over time, using FTIR
spectroscopy for bulk-fill flowable resin composite materials compared to
conventional flowable and regular resin composite materials.
Methods:
Eight resin composites were investigated
including flowable bulk-fill materials SureFil SDR (SDR), Venus bulk-fill
(VBF), x-tra base (XB), and Filtek Bulk Fill (FBF). Conventional flowable and
regular composite materials included: Venus Diamond flow (VDF), Grandioso
flow (GRF), Venus Diamond (VD), and Grandioso (GR). Degree of conversion (DC)
was assessed by Fourier transform infrared spectroscopy using attenuated
total reflectance technique. DC was measured for samples immediately
post-cure (n = 3), and after 24 h storage period
at 37 °C (n = 3). Results were
analysed using one-way analysis of variance (ANOVA), Bonferroni post hoc
test, and independent-samples t-test at α = 0.05 significance level.
Results:
Immediately
post-cure, the mean DC values of the different materials were in the
following order:
GRF > VDF > SDR > VBF > XB > GR > FBF < VD
and ranged from 34.7 to 77.1%. 24 h post-cure, DC values were in the
following order: GRF > VBF > VD > SDR > VDF > GR > XB < FBF
and ranged from 50.9 to 93.1%. GRF showed significantly higher DC values than
all other materials at both time intervals while XB and FBF showed
significantly lower values at 24 h post-cure.
Significance:
The 24 h
post-cure DC values of the bulk-fill composites SDR and VBF are generally
comparable to those of conventional composites studied; however, the
24 h post-cure DC values of XB and FBF were lower compared to the other
materials.
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البحث (3):
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عنوان البحث:
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Post-irradiation
hardness development, chemical softening, and thermal stability of bulk-fill
and conventional resin-composites
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تاريخ النشر:
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13-12-2014
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موجز عن البحث:
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Methods:
Six bulk-fill (SureFil SDR, Venus bulk fill,
X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram
bulk-fill) and eight conventional resin-composite materials (Grandioso flow,
Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus
Diamond, TPH Spectrum, and Filtek Z250) were tested (n = 5). Initial and 24 h (post-cure
dry storage) top and bottom microhardness values were measured. Microhardness
was re-measured after the samples were stored in 75% ethanol/water solution.
Thermal decomposition and filler content were assessed by TGA. Results were
analysed using one-way ANOVA and paired sample t-test (α = 0.05).
Results:
All materials showed significant increase of
microhardness after 24 h of dry storage which ranged from 100.1% to
9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all materials.
All materials showed significant decrease of microhardness after 24 h of
storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of
post-irradiation hardness development was positively correlated to the extent
of ethanol softening (R2 = 0.89, p < 0.001).
Initial thermal decomposition temperature assessed by TGA was variable and
was correlated to ethanol softening.
Conclusions:
Bulk-fill
resin-composites exhibit comparable bottom/top hardness ratio to conventional
materials at recommended manufacturer thickness. Hardness was affected to a
variable extent by storage with variable inorganic filler content and initial
thermal decomposition shown by TGA.
Clinical
significance:
The manufacturer
recommended depth of cure of bulk-fill resin-composites can be reached based
on the microhardness method. Characterization of the primary polymer network
of a resin-composite material should be considered when evaluating its
stability in the aqueous oral environment.
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البحث (4):
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عنوان البحث:
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Qualitative and quantitative
characterization of monomers of uncured bulk-fill and conventional
resin-composites using liquid chromatography/mass spectrometry
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رابط إلى البحث:
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تاريخ النشر:
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13-04-2015
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موجز عن البحث:
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Objectives:
The aim of this
study was to assess the resin matrix monomer composition of selected
bulk-fill and conventional resin-composite materials using reverse phase
liquid chromatography coupled with electron spray ionization mass
spectrometry.
Material and
methods:
Six bulk-fill (SureFil SDR, Venus Bulk Fill,
X-tra base, Filtek Bulk Fill flowable, Sonic Fill, and Tetric EvoCeram Bulk
Fill) and eight conventional resin-composites (Grandioso Flow, Venus Diamond
Flow, X-Flow, Filtek Supreme XTE, Grandioso, Venus Diamond, TPH Spectrum, and
Filtek Z250) were tested. For assessment of resin composition and relative
monomer amounts, uncured resin-composites were analysed with reverse phase
liquid chromatography/electron spray ionization mass spectrometry. log P values (a measure of hydrophobicity) of
detected compounds were calculated and their correlation to reverse phase
liquid chromatography retention time was explored. Data were analysed with
one-way ANOVA, Tukey post hoc test, Pearson correlation and regression
analyses at α = 0.05.
Results:
The main monomers detected were BisGMA, UDMA,
TEGDMA, and BisEMA. Monomers were detected at variable combinations in
different materials with significantly different relative amounts. Other
monomers were detected including HDDMA, DEGDMA, TCD-DI-HEA, and SDR-UDMA in
Grandioso flow, X-flow, Venus Diamond, and SureFil SDR respectively. A
positive correlation between log P and reverse
phase liquid chromatography retention time was detected (r2 = 0.62, p = 0.004).
Conclusions:
Resin composition of bulk-fill
resin-composites is comparable to that of conventional materials with the
exception of SureFil SDR. The relative hydrophobicity of dental monomers can
be determined by their reverse phase liquid chromatography retention time.
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البحث (5):
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عنوان البحث:
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Long-term sorption and solubility of
bulk-fill and conventional resin-composites in water and artificial saliva
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رابط إلى البحث:
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here
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تاريخ النشر:
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09-10-2015
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موجز عن البحث:
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Objectives:
To
assess sorption and solubility of several bulk-fill and conventional
resin-composites after one-year storage in water and artificial saliva (AS).
Methods:
Six
bulk-fill (SureFil SDR, Venus Bulk Fill, X-tra base, Filtek Bulk Fill
flowable, Sonic Fill, and Tetric EvoCeram Bulk Fill) and eight conventional
resin-composites (Grandioso Flow, Venus Diamond Flow, XFlow, Filtek Supreme
XTE, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested.
Disc shaped samples (n = 5) were randomly immersed into distilled water and
AS for one-year period and weighed at different time intervals. Data were
analysed using repeated measures ANOVA, one-way ANOVA, and Tukey’s post hoc
test (α = 0.05).
Results:
In
water, all materials (with the exception of X-Flow) reached a stable mass
within three months with a slow increase observed in AS up to one year.
Sorption values in water and AS for most materials were not significantly
different (p ≥ 0.2). Sorption and solubility values in water ranged from (6.5
μg/mm3 and −1.77 μg/mm3 respectively) for X-tra base to
(78.8 μg/mm3 and 44.77 μg/mm3 respectively) for X-Flow
(p < 0.005). Sorption of the polymer matrix in water ranged from 1.18% for
XB to 9.95 % for XF.
Conclusions:
Water
sorption and solubility of resin-composites are material-dependent and highly
affected by the filler loading and hydrophilicity of the resin matrix. BisEMA
and UDMA-BisEMA based resins appeared to be more hydrophobic than BisGMA
based systems. Water and AS, are generally comparable as storage media in
terms of water sorption.
Clinical significance:
Bulk-fill
materials and conventional resin-composites tested varied in terms of
sorption and solubility but both were considered stable in long–term water storage. The
composition of each material is critical and can affect the long-term
clinical performance of either type of resin–composites.
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البحث (6):
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عنوان البحث:
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Analysis of long-term monomer elution from
bulk-fill and conventional resin-composites using high performance liquid
chromatography
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رابط إلى البحث:
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here
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تاريخ النشر:
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14-11-2015
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موجز عن البحث:
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Objective:
The aim
of this study was to assess monomer elution from bulk-fill and conventional
resin-composites stored in different media using high performance liquid
chromatography (HPLC) for up to 3 months.
Methods:
Six
bulk-fill (SureFil SDR, Venus Bulk Fill, X-tra base, Filtek Bulk Fill
flowable, Sonic Fill, and Tetric EvoCeram Bulk Fill) and eight conventional
resin-composites (Grandioso Flow, Venus Diamond Flow, X-Flow, Filtek Supreme
XTE, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested.
Cylindrical samples (n = 5) were immersed in water, 70% ethanol/water solution
(70% E/W), and artificial saliva and stored at 37 °C for 24 h, 1 month, and 3
months. The storage solutions were analysed with HPLC. Data were analysed
with repeated measures ANOVA, one-way ANOVA, and Tukey post hoc test at α =
0.05.
Results:
Monomers
detected in water and artificial saliva were TEGDMA, DEGDMA, UDMA, and
TCD-DI-HEA. No eluted monomers were detected from X-tra base and Sonic fill
in these media. All monomers showed a variable extent of elution into 70% E/W
with significantly higher amounts than those detected in water and artificial
saliva. Significantly higher elution was detected from UDMA-BisEMA based
composites compared to BisGMA and BisGMA-BisEMA based systems in 70% E/W. The
rate of elution into different media varied between different monomers and
was highly dependent on the molecular weight of the eluted compounds.
Significance:
Elution
from bulk-fill resin-composites is comparable to that of conventional
materials despite their increased increment thickness. Monomer elution is highly
dependent on the hydrophobicity of the base monomers and the final network
characteristics of the resin-matrix.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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IADR/AADR/CADR
General Session & Exhibition
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تاريخ الإنعقاد:
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20-23 March 2013
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مكان
الإنعقاد:
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Seattle,
Washington, USA
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة:
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Degree
of Conversion of Bulk Fill Resin-Composites Over Time
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ملخص المشاركة:
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:Objectives
The purpose of this study is to assess
the degree of conversion (DC) immediate and after 24hr, using FTIR
spectroscopy for several bulk fill composite materials and compare it to that
of a l flowable and conventional resin-composite materials.
:Methods
Seven resin-composites were
investigated including three bulk fill materials SureFil SDR (SDR), Venus
bulk fill (VBF), and x-tra base (XB). Conventional flowable and regular
composite materials included: Venus Diamond flow (VDF), Grandioso flow (GRF),
Venus Diamond (VD), and Grandioso (GR). DC of the materials was assessed by
Fourier transform infrared spectroscopy (FTIR) using attenuated total
reflectance (ATR) technique. DC was measured for samples immediately
post-cure (n=3), and after 24-hour storage period at 37°C (n=3). Results were
analysed using one-way analysis of variance (ANOVA), Bonferroni post hoc
test, and independent-samples t-test at α=0.05 significance level.
:Results
Material
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DC immediately post-cure
(%)
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DC 24-hour post-cure
(%)
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SDR
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58.4 (0.5)a,b
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76.1 (0.6)a
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VBF
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55.7 (0.5)a,b,c
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79.2 (1.7)a
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XB
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53.9 (0.9)a,c
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62.1 (0.4)
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VDF
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62.0 (3.2)b
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70.6 (2.0)b
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GRF
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77.1 (3.5)
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93.1 (0.2)
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VD
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34.7 (2.6)
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79.0 (1.2)a
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GR
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50.0 (0.5)a,b,c
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69.1 (0.6)b
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:Conclusions
The ultimate DC values of the
low-stress bulk fill composites SDR and VBF are generally comparable to those
of conventional composites studied. On the other hand, the effect of the
significantly low ultimate DC of XB compared to other materials on physical
and mechanical performance worth further investigation
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المؤتمر (2):
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عنوان المؤتمر:
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IADR/AADR/CADR
General Session & Exhibition
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تاريخ الإنعقاد:
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9-13 September 2014
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مكان
الإنعقاد:
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Dubrovnik,
Croatia
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة:
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Effect
of Storage on Hardness of Bulk-Fill and Conventional Resin-Composites
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ملخص المشاركة:
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:Objectives
To measure the hardness of bulk fill
and conventional resin composite materials and assess hardness changes after
24h dry and 75% ethanol/water storage.
:Methods
Six bulk fill (SureFil SDR, Venus bulk
fill, x-tra base, Filtek bulk, Sonic fill, and Tetric EvoCeram bulk fill) and
eight conventional resin-composite materials (Grandioso flow, Venus Diamond
flow, X- flow, Filtek Supreme Ultra Flowble, Grandioso, Venus Diamond, TPH
Spectrum, and Filtek Z250) were tested.
Cylindrical specimens (2mm and 4mm thickness for conventional and bulk
fill materials respectively) were prepared (n=5). Initial and 24h post-cure
top and bottom Vickers hardness values were measured. Specimens were then stored for 24h in 75%
ethanol/water solution and hardness was measured again. Results were analysed
using one-way analysis of variance (ANOVA), Bonferroni post hoc test, and
paired sample t-test at α=0.05.
:Results
All materials showed significant
increase of hardness after 24h of dry storage which ranged from 100.1% (±
19.9) for SureFil SDR to 9.1 % (± 4.0) for Grandioso flow. 24h post-cure
hardness values ranged from (14.8 ±0.8) for Venus bulk fill to (97.6 ± 2.5)
for Grandioso and were positively correlated to filler loading (R2=
0.8). Bottom/top hardness ratio > 0.9 were exhibited by all materials. All
materials showed significant decrease of hardness after 24h of storage in 75%
ethanol/water solution in relation to their 24h post-cure hardness values.
SDR had the highest percentage decrease of 74.2% (± 1.9). The percentage
increase of hardness after 24h of dry storage was positively correlated to
the percentage decrease of hardness after 24h of storage in 75% ethanol/water
solution (R2= 0.8).
:Conclusion
Hardness
of all materials significantly increased over 24 hours. Bottom/top surface
hardness ratio of bulk fill composites are comparable to those of
conventional materials in spite of their increased increment thickness.
Hardness of all materials significantly decreased after 24h storage in 75%
ethanol/water solution.
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المؤتمر (3):
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عنوان المؤتمر:
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IADR/AADR/CADR
General Session & Exhibition
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تاريخ الإنعقاد:
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10-14 March 2015
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مكان
الإنعقاد:
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Boston,
Mass, USA
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة:
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Assessment
of Monomer Elution From Bulk-fill Resin-composites Over Time
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ملخص المشاركة:
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:Objectives
To assess resin composition and eluted
monomers from bulk fill resin-composites over a three-month storage period in
three different storage media
Methods:
Six
bulk fill composites were tested: SureFil SDR (SDR), Venus Bulk Fill (VBF),
x-tra base (XB), Filtek Bulk Fill (FBF), Sonic fill (SF), and Tetric EvoCeram
Bulk Fill (TEC). For assessment of resin composition, samples of uncured
resin-composites were analysed with liquid chromatography/mass spectrometry.
For assessment of monomer elution from cured material, cylindrical samples
(4x4mm) were prepared using the bulk fill technique (n=5). Immediately after
cure, the samples were immersed in water, 70% ethanol/water solution (70%
E/W), and artificial saliva (AS). Samples were stored at 37°C for periods of
24h, 1 month, and 3 months and the storage solutions were then analysed with
high pressure liquid chromatography. Data were analysed with repeated
measures ANOVA, one-way ANOVA, and Tukey HSD post hoc test at α=0.05.
Results:
All
materials contained UDMA except SF. FBF, TEC, and SF contained BisGMA. BISEMA
was present in all materials except TEC. TEGDMA was present in all materials
and DEGDMA was only identified in XB. All constituent monomers eluted from
cured samples stored in 70% E/W. In water and AS, only TEGDMA and UDMA were
detected in significantly lower amounts than those detected in 70%E/W.
Monomer elution decreased with time except UDMA that continued to elute in
similar amounts in AS until three months. XB and SF showed no eluted monomers
in both water and artificial saliva during all storage periods. SF showed
significantly lower amount of BisGMA and BisEMA release than all materials.
Conclusions:
Within
three-month storage period, SF showed the highest stability in all media. The
stability of UDMA based composites may be compromised by the continuous
release of UDMA in AS. BisGMA and BisEMA based systems shows more hydrophobic
behaviour and stability than UDMA based materials.
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