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Journal ArticleDOI

A comparative study on monomer elution and cytotoxicity of different adhesive restoration materials

16 Feb 2017-Journal of Adhesion Science and Technology (Taylor & Francis)-Vol. 31, Iss: 4, pp 414-429

TL;DR: Except for SR and QF, all other adhesive restoration materials showed different degrees of toxicity along with different monomer release kinetics, indicated that the cytotoxicity of the materials increased with the monomers release.

AbstractThis study evaluated monomer release and cytotoxicity of different adhesive restoration materials used for dental restorations. The extracts (1, 2, and 7 days) of three types of adhesive dental restoration materials, [Quixfill (QF), Silorane Restorative (SR), and Ketac N 100 Restorative (KR)], and the adhesive resins, [XP Bond (XP), Silorane Primer (SP), Ketac N 100 Primer (KP), and Silorane Bond (SB)] were analyzed using high performance liquid chromatography/mass spectrometry (HPLC-MS). The cytotoxicity levels were determined at different time points (24, 48, and 72 h) of cell culture using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. All adhesive resin materials showed monomer release at varying amounts with the highest release after 7 days. The lowest amount of release was observed in QF and the highest with KP. Bis-Phenol A (BPA) was not detected in SP and KR that contain bisphenol-A diglycidyl ether dimethacrylate (bis-GMA). Decamethylpenthasiloxane (D5) was ...

Topics: Dental restoration (51%)

Summary (3 min read)

Introduction

  • Resin-based composite materials and amalgam are both accepted as appropriate materials for the direct restoration of class I and II cavities in restorative dentistry.
  • In an attempt to overcome the disadvantages of glass ionomers, different types of glass ionomers have been developed including resin-modified glass ionomers. [7].
  • Several studies have shown the elution of different monomers such as bis-GMA, TEGDMA, and UDMA, from methacrylate-based resin restoration materials [12] but limited information is available on the monomer release from silorane-based restorative materials. [12–15].
  • The in vitro cytotoxicity tests have the advantage of easy detection of the influence of a material on isolated cells growing in culture plates.[17].
  • The null hypotheses tested were that adhesive restoration materials with different chemistry would not show significant difference in monomer elution kinetics and in cytotoxic effect on cell cultures.

Specimen preparation

  • Materials were placed in polytetrafluoroethylene molds and processed according to the manufacturer`s instructions in a laminar flow chamber (Bioair, Siziano, Italy).
  • The materials were then photopolymerized using light-emitting diode (LED, Elipar Free Light, 3 M ESPE, St. paul, USA; Light output: 1007 mW/cm2) according to the manufacturers’ instructions (40 s for QF, SR and KR; 20 s for XP, SP, SB, and KP).
  • The power output of the unit was measured with a radiometer (Cure-Rite, Dentsply-Caulk) before the placement of each restoration.
  • In total, 27 specimens of adhesive restoration materials and 54 specimens of primers and adhesives were prepared.

Preparation of extracts

  • All specimens from material groups were divided into three subgroups according to the extraction time intervals (1, 2, 7 days).
  • The disk-shaped specimens of all subgroups were immersed separately in 10 mL of culture medium (extract solution, DMEM, Sigma) immediately after photopolymerization.
  • The cell suspension was stained with Trypan Blue (Sigma Chemical Co.), counted using a Neubauer chamber and seeded in 24-well plates (Nunc, Sigma–Aldrich, Copenhagen, Denmark) at a density of 1 × 104 cells/well.

HPLC analysis

  • The analysis of extracts from adhesive materials and reference solutions of the monomers were performed using LC/MS System (Waters Alliance 2695 Separations Module HPLC System, Waters 2996 Photodiode Array Detector and Waters Micromass ZQ Mass Spectrometer, Meadows Instrumentation Inc., Bristol, USA).
  • A diode array detector was used to analyze the extracts except for SR, and the mass detector was chosen for SR extracts.
  • The injection volume was 20 μL and the elution time for the extracts was 15 min including bis-GMA, whereas for the remainder it was 6 min.
  • Calculating and comparing the area of the monomer peaks at different extraction time intervals performed a semi-quantitative comparison of the eluted silorane monomers.

Cultivation of L929 fibroblasts

  • The murine fibroblast cell line L929 in the third passage was obtained (HUKUK Cell Line Collection, no: 92123004 Foot and Mouth Disease Institute, Ankara, Turkey).
  • The cells were grown as monolayer culture in 25 cm2 flasks in Dubelcco’s modified Eagle’s medium (DMEM, Sigma Chemical Co.) supplemented with 10% fetal bovine serum (FBS, Hyclone, Utah, USA) and 1% penicillin/streptomycin at 37 °C in an incubator (Heraeus, Germany) containing 5% CO2 at 95–98% humidity.
  • Next, they were centrifuged and suspended in 24-well tissue culture plates of 1-mL aliquots, containing 5 × 104 cells/mL.

Mitochondrial activity

  • Cell metabolic activity was evaluated through the mitochondrial activity analysis using MTT test that detects the presence of succinic dehydrogenase enzyme (SDH) active in viable cells [22].
  • The succinic dehydrogenase activity has shown to be a reasonable representative of mitochondrial activity in the cells and reflects both cell number and activity.
  • Subsequently, the absorbance at 570 nm was measured using spectrophotometer with a microplate reader (Asys UVM 340, Biochrom, Victoria, Australia) with a reference of 690 nm.
  • The cell viability was calculated according to the Equation (1):.

Statistical analysis

  • Data were analyzed using a statistical software package (SPSS Software V.20, Chicago, IL, USA).
  • The differences in the release of each component from different adhesive materials were analyzed using one-way analysis of variance and repeated measures of variance analysis to determine the variability of the monomer elution between three different extraction time intervals.
  • Bonferroni post hoc test was used to determine the differences (1) Cell viability (%) = (Optical densities of test groups∕Optical densities of control groups) × 100 between the toxicity of the materials.
  • The relationship between the monomer release and toxicity was analyzed using the Spearman’s rho correlation test (−1 < r < 1).
  • P values less than 0.05 were considered to be statistically significant in all tests.

Morphologic assessment

  • L929 cells in the culture medium showed typical fibroblastic morphology .
  • The cells incubated with QF extracts for 48 h showed a spindle-shaped morphology similar to the typical fibroblastic morphology of control cells.
  • The cultures incubated with SR (1 and 2 days) extracts for 72 h were spindle-shaped in appearance similar to the control cells.
  • The cells incubated with KP extracts for 24 h were round in shape and additionally led to the enlargement of the intercellular space.
  • The cells treated with SP for 48 h and KR extracts for 72 h had morphologies similar to that of the cells incubated with KP extracts for 24 h .

Cell viability

  • After 72 h, 1- and 2-days extracts of SR were biocompatible to the cells and similar to the results of 48 h .
  • When the toxicities of the 1-day extracts of all tested materials after different incubation periods were compared, differences among the cell survival rates of KP, KR, SP, and XP were found to be statistically not significant (p > 0.05).
  • The chromatogram of silorane restorative extract of 2 days.

Discussion

  • This study was undertaken to measure the amount of monomers released from different types of adhesive restoration materials with different monomer types and to assess the cytotoxicity of these materials on L929 mouse fibroblast cultures at different time intervals.
  • The monomers were identified based on the mass spectra of each peak in the chromatogram.
  • The cytotoxic effect of adhesive materials on L929 cells was investigated using MTT assay where the reduction of MTT by viable cells is a good indicator of toxicity.[22].
  • The cytotoxicity of the materials increased with the monomer release where the correlation was significant after 48 h.

Conclusion

  • From this study, the following could be concluded: (1) All tested adhesive restorative materials showed monomer release kinetics at varying degrees at the time intervals tested.
  • (2) The least amount of monomer release was detected for the hybrid posterior resin composite, QF, containing UDMA, and TEGDMA. (4) The most toxic material was KP after 1 day but the differences among the toxicities after 2 and 7 days were not statistically significant between materials tested.
  • (5) After 48 h, 1- and 2-days extracts of SR and all extracts of QF were biocompatible with the cells.
  • (6) The amount of monomer release and cytotoxicity of the materials indicated weak but significant correlation especially after 48 h.

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Journal of Adhesion Science and Technology
ISSN: 0169-4243 (Print) 1568-5616 (Online) Journal homepage: https://www.tandfonline.com/loi/tast20
A comparative study on monomer elution and
cytotoxicity of different adhesive restoration
materials
Tuğba Toz, Arlin Kiremitçi, Anıl Sera Çakmak, Oya Ünsal Tan, Erhan Palaska,
Menemşe Gümüşderelioğlu & Mutlu Özcan
To cite this article: Tuğba Toz, Arlin Kiremitçi, Anıl Sera Çakmak, Oya Ünsal Tan, Erhan Palaska,
Menemşe Gümüşderelioğlu & Mutlu Özcan (2017) A comparative study on monomer elution
and cytotoxicity of different adhesive restoration materials, Journal of Adhesion Science and
Technology, 31:4, 414-429, DOI: 10.1080/01694243.2016.1215768
To link to this article: https://doi.org/10.1080/01694243.2016.1215768
Published online: 01 Aug 2016.
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Citing articles: 1 View citing articles

JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 2017
VOL. 31, NO. 4, 414429
http://dx.doi.org/10.1080/01694243.2016.1215768
A comparative study on monomer elution and cytotoxicity of
dierent adhesive restoration materials
Tuğba Toz
a
, Arlin Kiremitçi
b
, Anıl Sera Çakmak
c,d
, Oya Ünsal Tan
e
, Erhan Palaska
e
,
Menemşe Gümüşderelioğlu
c,d
and Mutlu Özcan
f
a
Faculty of Dentistry, Department of Restorative Dentistry, School of Dentistry, Istanbul Medipol University,
Istanbul, Turkey;
b
Faculty of Dentistry, Department of Restorative Dentistry, Hacettepe University, Ankara,
Turkey;
c
Faculty of Engineering, Department of Chemical Engineering, Hacettepe University, Ankara, Turkey;
d
Faculty of Engineering, Department of Bioengineering, Hacettepe University, Ankara, Turkey;
e
Faculty of
Pharmacology, Department of Pharmaceutical Chemistry, Hacettepe University, Ankara, Turkey;
f
Dental
Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental
Materials Science, University of Zurich, Zurich, Switzerland
ABSTRACT
This study evaluated monomer release and cytotoxicity of dierent
adhesive restoration materials used for dental restorations. The
extracts (1, 2, and 7days) of three types of adhesive dental restoration
materials, [Quixll (QF), Silorane Restorative (SR), and Ketac N 100
Restorative (KR)], and the adhesive resins, [XP Bond (XP), Silorane Primer
(SP), Ketac N 100 Primer (KP), and Silorane Bond (SB)] were analyzed
using high performance liquid chromatography/mass spectrometry
(HPLC-MS). The cytotoxicity levels were determined at dierent
time points (24, 48, and 72h) of cell culture using 3-(4,5-dimethyl-
2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. All
adhesive resin materials showed monomer release at varying amounts
with the highest release after 7days. The lowest amount of release
was observed in QF and the highest with KP. Bis-Phenol A (BPA) was
not detected in SP and KR that contain bisphenol-A diglycidyl ether
dimethacrylate (bis-GMA). Decamethylpenthasiloxane (D5) was not
eluted from SR. Except for SR and QF, all other adhesive restoration
materials showed dierent degrees of toxicity along with dierent
monomer release kinetics. The correlation between the monomer
release and cytotoxicity of the materials indicated that the cytotoxicity
of the materials increased with the monomer release (Spearmans rho
correlation coecient – r). The correlation after 48h was statistically
signicant (r=−0.342, p=0.017).
Introduction
Resin-based composite materials and amalgam are both accepted as appropriate materials
for the direct restoration of class I and II cavities in restorative dentistry. However, according
to the current dental concepts, resin composites are considered as the most suitable direct
posterior lling materials since they also allow for minimal invasive restorations.[1]
KEYWORDS
Adhesion; cytotoxicity;
high-performance liquid
chromatography; L929 cell
culture; monomer release
ARTICLE HISTORY
Received 12 May 2016
Revised 7 July 2016
Accepted 12 July 2016
© 2016 Informa UK Limited, trading as Taylor & Francis Group
CONTACT Tuğba Toz ttoz@medipol.edu.tr

JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY 415
e polymerizable matrix of resin materials usually contains one or more base monomers
such as bisphenol-A diglycidyl ether dimethacrylate (bis-GMA) and/or urethane dimeth-
acrylate (UDMA), diluent co-monomers such as ethylene glycol dimethacrylate (EGDMA)
and/or triethylene glycol dimethacrylate (TEGDMA), and various additives such as pho-
toinitiators (e.g. camphoroquinone), co-initiators (e.g. dimethyl-aminobenzoic-acid- ester),
polymerization inhibitors and photostabilizers (e.g. benzophenone).[2] Despite the improve-
ments in adhesive technologies, drawbacks such as polymerization shrinkage within such
materials could not be eliminated.[3] In order to overcome the shortcomings of conventional
resin-based composites, dental siloranes have been introduced that consist of a new organic
matrix.[4] Siloranes present low polymerization shrinkage due to the ring-opening oxirane
monomer, increased hydrophobicity, and thereby increased biocompatibility compared to
the conventional resin-based composites.[5]
As an alternative to resin composites, glass ionomers are also commonly used for a num-
ber of applications such as base or liner materials, as luting cements for indirect restorations,
or as temporary or permanent restorative materials for direct restorations. Glass ionomers
present several advantages of biocompatibility, low coecient of thermal expansion, the
ability to adhere to the moist tooth structure without necessitating an intermediate agent
that decreases the chair-side of the treatment procedure and anticariogenic properties due
to uoride release compared to methacrylate-based resin composites. However, they have
some drawbacks such as poor polishability and less favorable mechanical properties, surface
wear, or decreased fracture resistance over time.[6] In an attempt to overcome the disad-
vantages of glass ionomers, dierent types of glass ionomers have been developed including
resin-modied glass ionomers.[7]
e application of adhesive restoration materials in dentistry has been extensively pro-
moted over the last decade.[8] However, concerns in the dentistry over the generation
of biodegradation products have also increased and possible eects of byproducts from
composite resin matrix degradation on the function of host cells and micro-organisms are
being questioned.[9] e release of unpolymerized components from the polymerizable
resin matrix as a result of incomplete polymerization of adhesive restoration materials may
inuence the biocompatibility of the restorations.[2] Consequently, the amount of mono-
mer elution plays an important role in biocompatibility of adhesive restorative materials.
Chromatographic techniques are helpful in the analysis of compounds released from
resin-based dental llings. e components extracted from resin-modied glass ionomers,
compomers, and resin composites could be determined using gas chromatography/mass
spectrometry (MS).[10] Unfortunately, base-monomer analysis by gas chromatography is
almost impossible due to their low volatility and decomposition at higher temperature in the
injection port of the gas chromatograph. One of the few available techniques suitable for the
analysis of high-molecular-mass compounds is high-performance liquid chromatography
(HPLC), mainly coupled with mass spectrophotometry or diode array detection.[11] Several
studies have shown the elution of dierent monomers such as bis-GMA, TEGDMA, and
UDMA, from methacrylate-based resin restoration materials [12] but limited information
is available on the monomer release from silorane-based restorative materials.[12–15]
By denition, cytotoxicity of an agent is the cascade of molecular events that interferes
with macromolecular synthesis, causing unequivocal functional and structural damage
in a cell culture. e interactions of the materials and their components with the cells
at a molecular level are responsible for tissue reactions such as inammation, necrosis,

416 T. TOZ ET AL.
immunological alterations, genotoxicity, and apoptosis.[16] e in vitro cytotoxicity tests
have the advantage of easy detection of the inuence of a material on isolated cells growing
in culture plates.[17] A number of methods have been developed such as lactate dehydro-
genase assay, bromodeoxiuridine assay [18], and uorescence microscopy [19] in order to
investigate the cytotoxicity of dental resin materials. However, 3-(4,5-dimethyl-2-thiazolyl)-
2,5- diphenyl-2H tetrazolium bromide (MTT) assay is considered to be more useful to
estimate cell densities in small culture volumes and has some advantages, such as simplicity,
accuracy, reliability, and eciency.[20]
e objective of this study, therefore, was to measure the amount of monomers released
from dierent types of adhesive restoration materials with dierent monomer types using
HPLC-MS and HPLC-Ultraviolet (UV) and to assess the cytotoxicity of these materials on
L929 mouse broblast cultures at dierent time intervals. e null hypotheses tested were
that adhesive restoration materials with dierent chemistry would not show signicant
dierence in monomer elution kinetics and in cytotoxic eect on cell cultures.
Materials and methods
Specimen preparation
Disk-shaped specimens from the tested restorative materials including etch-and-rinse adhe-
sive system ‘XP’ (XP Bond, Dentsply De Trey, Germany), posterior hybrid composite ‘QF’
(Quixll, Dentsply De Trey, Germany), silorane composite ‘SR’ used with its own self-etch
adhesive system including primer ‘SP’ and bond ‘SB’ (Silorane, 3M ESPE, St. Paul, USA),
and nano-ionomer ‘KR’ applied with its own primer ‘KP’ (Ketac N 100, GC, Tokyo Japan)
were prepared (Table 1). Materials were placed in polytetrauoroethylene (Teon) molds
and processed according to the manufacturer`s instructions in a laminar ow chamber
(Bioair, Siziano, Italy). e etch-and-rinse adhesive system (XP), primer (SP and KP), and
adhesive resin (SB) disks were 5mm in diameter and 1mm in thickness and adhesive res-
toration materials (QF, SR, and KR) were 5mm in diameter and 4mm in thickness. e
adhesive restorative materials were applied in two layers, while the primers and adhesives
were applied in one layer and the surfaces of all materials were covered with a transpar-
ent strip to prevent the formation of air-inhibited surface layer. e materials were then
photopolymerized using light-emitting diode (LED, Elipar Free Light, 3M ESPE, St. paul,
USA; Light output: 1007mW/cm
2
) according to the manufacturers’ instructions (40 s for
QF, SR and KR; 20 s for XP, SP, SB, and KP). e power output of the unit was measured
with a radiometer (Cure-Rite, Dentsply-Caulk) before the placement of each restoration.
In total, 27 specimens of adhesive restoration materials and 54 specimens of primers and
adhesives were prepared.
High-performance liquid chromatography
Preparation of extracts
All specimens from material groups were divided into three subgroups (n=9 for the adhe-
sive restoration materials; n=18 for primers and adhesives) according to the extraction
period (1, 2, 7days). e extraction period was adjusted accordingly for the methyltetra-
zolium (MTT) test procedure. Immediately aer photopolymerization, the specimens in

JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY 417
each subgroup were weighed (Mettler Toledo, Colombus, USA) and, except for SR, spec-
imens in all groups were placed separately into 10mL of 70% methanol/water solution
(Sigma–Aldrich, St Louis, MO USA). e extracting medium for the SR groups was pure
methanol solution as it is not soluble in methanol/water solution. e specimens were
incubated for 1, 2, and 7days at 37°C in dark. Aer the incubation period, the specimens
were removed and the extracts were analyzed using HPLC.
Table 1.The brands, types, manufacturers, batch numbers, and chemical compositions of the adhesive
restorative materials tested in this study.
Adhesive restor-
ative system
Type of the
material Manufacturer Batch number Chemical composition
Adhesive restora-
tive system
Type of the
material
Manufacturer Batch number Chemical composition
XP bond Two-step etch
and rinse
adhesive
system
Dentsply, De
Trey, Konstanz
Germany
0,707,000,223 Carboxylic acid-modified dimeth-
acrylate,phosphoric acid-modified
acrylate resin,urethane dimeth-
acrylate, TEGDMA,HEMA, butylated
benzenediol,ethyl-4-dimethylam-
inobenzoate,camphorquinone,
functionalizedamorphous silica,
t-butanol
Quixfill Methacyr-
late-based
hybrid pos-
terior resin
composite
07,030,000,799 Resin: urethane dimethacrylate
(UDMA);triethyleneglycol di-
methacrylate (TEGDMA); di- and
trimethacrylate resins; carboxylic
acid-modified dimethacrylate resin;
butylated hydroxy tolüene (BHT); UV
stabilizer, camphorquinone; ethyl-4-
dimethylaminobenzoateFillers: sila-
nated strontium aluminumsodium
fluoride phosphate silicate glass
Silorane primer Primer 3M ESPE,St. Paul,
USA
20,090,220 2-Hydroxyethyl methacrylate (HEMA)
bisphenol A diglycidyl ether
dimethacrylate (bis-GMA), water,
ethanol, phosphoric acid-meth-
acryloxy-hexylester mixture,
silane treated silica 1,6-Hexanediol
dimethacrylate,copolymer of acrylic
and itaconic acid,(Dimethylamino)
ethyl methacrylate,dl-Camphorqui-
none,phosphine oxide
Silorane bond Adhesive resin 20,090,220 Substituted dimethacrylate Silane
treated silica, triethylene glycol di-
methacrylate (TEGDMA), phosphoric
acid methacryloxy-hexylesters-
dl-Camphorquinone 1,6-Hexanediol
dimethacrylate
Silorane Silorane
restorative
20,090,220 3,4 epoxycyclohexylethylcyclopolyme-
thylsiloxane,bis-3,4-epoxycyclohex-
ylethylphenylmethylsilane, silanized
glass,yittrium floride, camphorqui-
none
Ketac N 100
Primer
Nano-ionomer
primer
3M ESPE 20,070,917 Water, HEMA, acrylic/itaconic acid
copolymer, photo-initiators
Ketac N 100 Photopolym-
erizedna-
no-ionomer
restorative
20,070,917 Paste A: silane-treated glass, si-
lane-treated ZrO2silica, silane-treat-
ed silica, PEGDMA, HEMA, bis-GMA,
TEGDMAPaste B: silane-treated
ceramic, silane-treated silica, water,
HEMA, acrylic/itaconic acidcopol-
ymer

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Abstract: The objective of this study was to evaluate the biocompatibility and mechanical properties of two commercially available and one experimental periodontal dressing materials. The cytotoxicity of Periobond ® , Barricaid ® and one experimental periodontal dressing based on Exothane ® 8 monomer was tested on 3T3/NIH mouse fibroblast. Genotoxicity was assessed by micronuclei formation, and cell alterations were analyzed using light microscopy. Both biological assays were performed using the eluate obtained from specimens after 24, 72, or 168 hours of incubation. Mechanical characterization was assessed through the ultimate tensile strength and the water sorption and solubility tests. The significance level of α = 0.05 was used for all statistical analyses. All the materials promoted a cell viability lower than 60% in all evaluated times. In general, the cell viability was significantly reduced after 72 and 168h of specimens' incubation. Considering the factor material, there were not statistical differences in the cell viability (p = 0.156). The genotoxicity was not statistically significant among the groups in the different periods of time (p > 0.05). Differences in the ultimate tensile strength values were not statistically significant different among the groups (p = 0.125). Periobond ® showed the higher water sorption values (p < 0.001). Regarding solubility, there were no statistical differences between the groups (p = 0.098). All the periodontal dressing materials evaluated in this study exerted a cytotoxic effect against mouse fibroblasts, and their toxicity became more evident over time. Among the materials evaluated, the experimental light-cure type has shown overall similar properties to the commercial references.

Journal ArticleDOI
Abstract: This study aimed to evaluate the in vitro effect of the novel bioactive adhesive monomer CMET, a calcium salt of 4-methacryloxyethyl trimellitate acid (4-MET), on human dental pulp stem cells (hDPSCs) and its capacity to induce tertiary dentin formation in a rat pulp injury model. Aqueous solutions of four tested materials [4-MET, CMET, Ca(OH)2, and mineral trioxide aggregate (MTA)] were added to the culture medium upon confluence, and solvent (dH2O) was used as a control. Cell proliferation was assessed using the Cell Counting Kit-8 assay, and cell differentiation was evaluated by real-time quantitative reverse transcription-polymerase chain reaction. The mineralization-inducing capacity was evaluated using alizarin red S staining and an alkaline phosphatase activity assay. For an in vivo experiment, a mechanical pulp exposure model was prepared on Wistar rats; damaged pulp was capped with Ca(OH)2 or CMET. Cavities were sealed with composite resin, and specimens were assessed after 14 and 28 days. The in vitro results showed that CMET exhibited the lowest cytotoxicity and highest odontogenic differentiation capacity among all tested materials. The favorable outcome on cell mineralization after treatment with CMET involved p38 and c-Jun N-terminal kinases signaling. The nuclear factor kappa B pathway was involved in the CMET-induced mRNA expression of odontogenic markers. Similar to Ca(OH)2, CMET produced a continuous hard tissue bridge at the pulp exposure site, but treatment with only CMET produced a regular dentinal tubule pattern. The findings suggest that (1) the evaluated novel bioactive adhesive monomer provides favorable biocompatibility and odontogenic induction capacity and that (2) CMET might be a very promising adjunctive for pulp-capping materials.

References
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Journal ArticleDOI
TL;DR: A tetrazolium salt has been used to develop a quantitative colorimetric assay for mammalian cell survival and proliferation and is used to measure proliferative lymphokines, mitogen stimulations and complement-mediated lysis.
Abstract: A tetrazolium salt has been used to develop a quantitative colorimetric assay for mammalian cell survival and proliferation. The assay detects living, but not dead cells and the signal generated is dependent on the degree of activation of the cells. This method can therefore be used to measure cytotoxicity, proliferation or activation. The results can be read on a multiwell scanning spectrophotometer (ELISA reader) and show a high degree of precision. No washing steps are used in the assay. The main advantages of the colorimetric assay are its rapidity and precision, and the lack of any radioisotope. We have used the assay to measure proliferative lymphokines, mitogen stimulations and complement-mediated lysis.

46,508 citations


"A comparative study on monomer elut..." refers methods in this paper

  • ...Cell metabolic activity was evaluated through the mitochondrial activity analysis using MTT test that detects the presence of succinic dehydrogenase enzyme (SDH) active in viable cells [22]....

    [...]

  • ...[33] In this study, the cytotoxic effect of adhesive materials on L929 cells was investigated using MTT assay where the reduction of MTT by viable cells is a good indicator of toxicity.[22] According to the data obtained from the MTT test, except SR and QF, all restorative materials showed different degrees of toxicity....

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Journal ArticleDOI
TL;DR: A long survival rate for posterior composite restorations can be expected provided that patient, operator and materials factors are taken into account when the restorATIONS are performed.
Abstract: Resin composites have become the first choice for direct posterior restorations and are increasingly popular among clinicians and patients. Meanwhile, a number of clinical reports in the literature have discussed the durability of these restorations over long periods. In this review, we have searched the dental literature looking for clinical trials investigating posterior composite restorations over periods of at least 5 years of follow-up published between 1996 and 2011. The search resulted in 34 selected studies. 90% of the clinical studies indicated that annual failure rates between 1% and 3% can be achieved with Class I and II posterior composite restorations depending on several factors such as tooth type and location, operator, and socioeconomic, demographic, and behavioral elements. The material properties showed a minor effect on longevity. The main reasons for failure in the long term are secondary caries, related to the individual caries risk, and fracture, related to the presence of a lining or the strength of the material used as well as patient factors such as bruxism. Repair is a viable alternative to replacement, and it can increase significantly the lifetime of restorations. As observed in the literature reviewed, a long survival rate for posterior composite restorations can be expected provided that patient, operator and materials factors are taken into account when the restorations are performed.

628 citations


"A comparative study on monomer elut..." refers background in this paper

  • ...However, according to the current dental concepts, resin composites are considered as the most suitable direct posterior filling materials since they also allow for minimal invasive restorations.[1] KEYWORDS...

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Journal ArticleDOI
TL;DR: The results of these studies suggest that elution of leachable components from composites is rapid, with the majority being released within a matter of hours.
Abstract: A significant amount of residual monomer or short chain polymers remain unbound in set composite material. Due to its potential impact on both the biocompatibility and the structural stability of the restoration, many investigators have studied the elution of these unbound molecules into aqueous media. The results of these studies suggest that elution of leachable components from composites is rapid, with the majority being released within a matter of hours. Weight losses of up to 2% of the mass of the composite have been reported under certain conditions. The studies have also shown that the extent and rate of elution of components from composites is dependent upon several factors. The quantity of leachables has been correlated to the degree of cure of the polymer network. The composition and solubility characteristics of the extraction solvent influence the kinetics and mechanism of the elution process. Elution is generally thought to occur via diffusion of molecules through the resin matrix, and is therefore dependent upon the size and chemical characteristics of the leachable species.

594 citations


"A comparative study on monomer elut..." refers result in this paper

  • ...This high amount release from the smallest monomer HEMA (130 g/ mol) is in accordance with a previous study.[25] Smaller molecules have an enhanced mobility and could be eluted at a faster rate than larger bulkier molecules....

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Journal ArticleDOI
TL;DR: Water sorption and solubility of six proprietary composite resin materials were assessed, and monomers eluted from the organic matrix during water storage identified, and triethyleneglycol dimethacrylate was the main monomer released.
Abstract: Water sorption and solubility of six proprietary composite resin materials were assessed, and monomers eluted from the organic matrix during water storage identified. Water sorption and solubility tests were carried out with the following storage times: 4 h, 24 h and 7, 60 and 180 days. After storage, water sorption and solubility were determined. Eluted monomers were analysed by high performance liquid chromatography (HPLC). Correlation between the retention time of the registered peak and the reference peak was observed, and UV-spectra confirmed the identity. The results showed an increase in water sorption until equilibrium for all materials with one exception. The solubility behaviour of the composite resin materials tested revealed variations, with both mass decrease and increase. The resin composition influences the water sorption and solubility behaviour of composite resin materials. The HPLC analysis of eluted components revealed that triethyleneglycol dimethacrylate (TEGDMA) was the main monomer released. Maximal monomer concentration in the eluate was observed after 7 days. During the test period, quantifiable quantities of urethanedimethacrylate (UEDMA) monomer were observed, whereas 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane (Bis-GMA) was only found in detectable quantities. No detectable quantities of bisphenol-A were observed during the test period.

313 citations


"A comparative study on monomer elut..." refers background in this paper

  • ...In some studies, BPA was detected [30], whereas in others is not [31]....

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Journal ArticleDOI
Abstract: Previous studies have shown a wide range of pulpal reactions to dentin bonding systems and a poor correlation between in vitro and in vivo toxicity of dentin bonding agents. Because dentin bonding agents are composed of multiple components which may diffuse through dentin, we hypothesized that these components may cause cytotoxicity through interactive (synergistic) effects. We investigated the cytotoxicities of four dentin bonding components--HEMA, Bis-GMA, TEGDMA, and UDMA--and interactive effects for three binary combinations of the dentin bonding components--HEMA and Bis-GMA, Bis-GMA and TEGDMA, and TEGDMA and UDMA. Cytotoxicities to Balb/c 3T3 mouse fibroblasts were measured by the MTT assay. Concentrations which caused 50% toxicity compared with controls (TC50 values) were compared, and the interactive effects were determined by evaluation of the differences between observed and expected MTT activities of the cells. The ranks of toxicity of the dentin bonding components in terms of TC50 values were as follows: Bis-GMA > UDMA > TEGDMA >>> HEMA (least toxic) after 24- and 72-hour exposures. As binary combinations, the three combinations of dentin bonding components interacted in three ways--synergism, additivism, and antagonism--which were influenced by the concentrations of both components. The longer period of exposure resulted in a significant increase in the cytotoxicity of the dentin bonding components and combinations. The findings indicate that both exposure time and the interactions between the dentin bonding components may be important parameters in determining the cytotoxicity of dentin bonding agents in vivo.

283 citations


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Q1. What are the contributions mentioned in the paper "A comparative study on monomer elution and cytotoxicity of different adhesive restoration materials" ?

This study evaluated monomer release and cytotoxicity of different adhesive restoration materials used for dental restorations.