scholarly journals In Vitro Wear of New Indirect Resin Composites

2009 ◽  
Vol 34 (4) ◽  
pp. 423-428 ◽  
Author(s):  
V. Jain ◽  
J. A. Platt ◽  
B. K. Moore ◽  
G. A. Borges
Keyword(s):  
Clinical Relevance ◽  
Wear Testing ◽  
Resin Composites ◽  
Testing Conditions ◽  
Full Coverage ◽  
Indirect Composites ◽  
Wear Tests

Clinical Relevance The application of indirect resin composites for full-coverage restorative purposes still remains a concern due to wear. New indirect composites behave differently under different wear-testing conditions. Overall, Belleglass-NG showed the lowest wear when tested in vitro under different wear tests.

scholarly journals In Vitro Comparison of Microleakage of Posterior Resin Composites With and Without Liner Using Two-Step Etch-and-Rinse and Self-etch Dentin Adhesive Systems

2011 ◽  
Vol 36 (2) ◽  
pp. 213-221 ◽  
Author(s):  
S Kasraei ◽  
M Azarsina ◽  
S Majidi
Keyword(s):  
Clinical Relevance ◽  
Class Ii ◽  
Resin Composites ◽  
Adhesive Systems ◽  
Sandwich Technique ◽  
Composite Restorations ◽  
Etch And Rinse ◽  
Self Etch ◽  
In Vitro Comparison

Clinical Relevance The use of resin-modified glass ionomers as cavity liners in the closed-sandwich technique reduced microleakage in Class II composite restorations.

scholarly journals Marginal Adaptation and Micropermeability of Class II Cavities Restored with Three Different Types of Resin Composites—A Comparative Ten-Month In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1660
Author(s):  
Sevda Mihailova Yantcheva
Keyword(s):  
Methylene Blue ◽  
In Vitro Study ◽  
Sem Analysis ◽  
Marginal Adaptation ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Gingival Margin ◽  
Different Types ◽  
Ageing Period

The development of composite materials is subject to the desire to overcome polymerization shrinkage and generated polymerization stress. An indicator characterizing the properties of restorative materials, with specific importance for preventing secondary caries, is the integrity and durability of marginal sealing. It is a reflection of the effects of polymerization shrinkage and generated stress. The present study aimed to evaluate and correlate marginal integrity and micropermeability in second-class cavities restored with three different types of composites, representing different strategies to reduce polymerization shrinkage and stress: nanocomposite, silorane, and bulk-fill composite after a ten-month ageing period. Thirty standardized class ΙΙ cavities were prepared on extracted human molars. Gingival margins were 1 mm apical to the cementoenamel junction. Cavities were randomly divided into three groups, based on the composites used: FiltekUltimate-nanocomposite; Filtek Silorane LS-silorane; SonicFill-bulk-fill composite. All specimens were subjected to thermal cycles after that, dipped in saline for 10-mounds. After ageing, samples were immersed in a 2% methylene blue. Thus prepared, they were covered directly with gold and analyzed on SEM for assessment of marginal seal. When the SEM analysis was completed, the teeth were included into epoxy blocks and cut longitudinally on three slices for each cavity. An assessment of microleakage on stereomicroscope followed. Results were statistically analyzed. For marginal seal evaluation: F.Ultimate and F.Silorane differ statistically with more excellent results than SonicFill for marginal adaptation to the gingival margin, located entirely in the dentin. For microleakage evaluation: F.Ultimate and F.Silorane differ statistically with less microleakage than SonicFill. Based on the results obtained: a strong correlation is found between excellent results for marginal adaptation to the marginal gingival ridge and micropermeability at the direction to the axial wall. We observe a more significant influence of time at the gingival margin of the cavities. There is a significant increase in the presence of marginal fissures (p = 0.001). A significant impact of time (p < 0.000) and of the material (p < 0.000) was found in the analysis of the microleakage.

scholarly journals Homozygous MTAP deletion in primary human glioblastoma is not associated with elevation of methylthioadenosine

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yasaman Barekatain ◽  
Jeffrey J. Ackroyd ◽  
Victoria C. Yan ◽  
Sunada Khadka ◽  
Lin Wang ◽  
...  
Keyword(s):  
Clinical Relevance ◽  
Homozygous Deletion ◽  
In Vitro Models ◽  
Arginine Methyltransferase ◽  
Human Glioblastoma ◽  
Primary Glioblastoma ◽  
Methylthioadenosine Phosphorylase ◽  
Metabolomic Profiling

AbstractHomozygous deletion of methylthioadenosine phosphorylase (MTAP) in cancers such as glioblastoma represents a potentially targetable vulnerability. Homozygous MTAP-deleted cell lines in culture show elevation of MTAP’s substrate metabolite, methylthioadenosine (MTA). High levels of MTA inhibit protein arginine methyltransferase 5 (PRMT5), which sensitizes MTAP-deleted cells to PRMT5 and methionine adenosyltransferase 2A (MAT2A) inhibition. While this concept has been extensively corroborated in vitro, the clinical relevance relies on exhibiting significant MTA accumulation in human glioblastoma. In this work, using comprehensive metabolomic profiling, we show that MTA secreted by MTAP-deleted cells in vitro results in high levels of extracellular MTA. We further demonstrate that homozygous MTAP-deleted primary glioblastoma tumors do not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma. These findings highlight metabolic discrepancies between in vitro models and primary human tumors that must be considered when developing strategies for precision therapies targeting glioblastoma with homozygous MTAP deletion.

scholarly journals Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2769
Author(s):  
Jonne Oja ◽  
Lippo Lassila ◽  
Pekka K. Vallittu ◽  
Sufyan Garoushi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Accelerated Aging ◽  
Wear Depth ◽  
Resin Composites ◽  
Expiration Date ◽  
Dental Resin ◽  
Hydrothermal Aging ◽  
Dental Resin Composites

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

scholarly journals Synthesis, Characterization and Testing of Antimicrobial Activity of Composites of Unsaturated Polyester Resins with Wood Flour and Silver Nanoparticles

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1122
Author(s):  
Przemysław Pączkowski ◽  
Andrzej Puszka ◽  
Malgorzata Miazga-Karska ◽  
Grażyna Ginalska ◽  
Barbara Gawdzik
Keyword(s):  
Silver Nanoparticles ◽  
Staphylococcus Epidermidis ◽  
Polyester Resin ◽  
Wood Flour ◽  
Unsaturated Polyester ◽  
Thermomechanical Properties ◽  
Resin Composites ◽  
Polyester Resins ◽  
Before And After

This paper presents the properties of the wood-resin composites. For improving their antibacterial character, silver nanoparticles were incorporated into their structures. The properties of the obtained materials were analyzed in vitro for their anti-biofilm potency in contact with aerobic Gram-positive Staphylococcus aureus and Staphylococcus epidermidis; and aerobic Gram-negative Escherichia coli and Pseudomonas aeruginosa. These pathogens are responsible for various infections, including those associated with healthcare. The effect of silver nanoparticles incorporation on mechanical and thermomechanical properties as well as gloss were investigated for the samples of composites before and after accelerating aging tests. The results show that bacteria can colonize in various wrinkles and cracks on the composites with wood flour but also the surface of the cross-linked unsaturated polyester resin. The addition of nanosilver causes the death of bacteria. It also positively influences mechanical and thermomechanical properties as well as gloss of the resin.

scholarly journals Comparison of Proximal Contacts of Class II Resin Composite Restorations In Vitro

2006 ◽  
Vol 31 (6) ◽  
pp. 688-693 ◽  
Author(s):  
B. A. C. Loomans ◽  
N. J. M. Opdam ◽  
F. J. M. Roeters ◽  
E. M. Bronkhorst ◽  
R. C. W. Burgersdijk
Keyword(s):  
Clinical Relevance ◽  
Resin Composite ◽  
Class Ii ◽  
Composite Restorations ◽  
Composite Restoration

Clinical Relevance When placing a Class II resin composite restoration, the use of sectional matrix systems and separation rings to obtain tight proximal contacts is recommended.

scholarly journals Evaluation of Wear Behaviour in Metallic Binders Employed in Diamond Tools for Cutting Stone

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3988
Author(s):  
Fátima Ternero ◽  
Pedro M. Amaral ◽  
Jorge Cruz Fernandes ◽  
Luís Guerra Rosa
Keyword(s):  
Wear Behavior ◽  
Wear Behaviour ◽  
Empirical Expression ◽  
Testing Conditions ◽  
Diamond Tools ◽  
Test Methodology ◽  
Different Types ◽  
Stone Material ◽  
The Difference ◽  
Wear Tests

A type of disc-on-plate test methodology was used to determine the wear behavior of metallic binders employed in the manufacturing of diamond impregnated tools. The disc consists of a special circular wheel that allows the binder materials alone (i.e., without diamond, but sintered under conditions identical to those of the complete tool) to be tested against a plate of stone material under pre-determined testing conditions. The testing conditions are intended to be equivalent to those used in the industrial processes. Using plates of five types of granite and one type of marble, this work comprises wear tests of 15 different types of metallic binders and two sintering modes conducted under, at least, three different values of contact-force. The analysis of the results demonstrated that the wear of the binders can be related to their mechanical properties through an empirical expression. The larger the difference between the characteristics of the tribological pair (binder versus stone), the higher is the correlation between the experimental wear data and the values given by the empirical expression. The relationships presented in this work allow predicting the wear behavior of the binder, and therefore may help in the design process of diamond tools. There was a clear difference between the wear behavior of metallic binders when they were employed against the two main classes of stone under analysis (marble and granite).

Subcritical crack growth and in vitro lifetime prediction of resin composites with different filler distributions

2012 ◽  
Vol 28 (9) ◽  
pp. 985-995 ◽  
Author(s):  
Bárbara P. Ornaghi ◽  
Marcia M. Meier ◽  
Vinícius Rosa ◽  
Paulo F. Cesar ◽  
Ulrich Lohbauer ◽  
...  
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Lifetime Prediction ◽  
Resin Composites

Comparison of Temperature Changes in the Pulp Chamber Induced by Various Light Curing Units, In Vitro

10.2341/05-26 ◽  
2006 ◽  
Vol 31 (2) ◽  
pp. 261-265 ◽  
Author(s):  
A. R. Yazici ◽  
A. Müftü ◽  
G. Kugel ◽  
R. D. Perry
Keyword(s):  
Clinical Relevance ◽  
Critical Factor ◽  
Pulp Chamber ◽  
Temperature Changes ◽  
Thermal Transfer ◽  
Light Curing

Clinical Relevance The thickness of the residual dentin is a critical factor in the reducing thermal transfer to pulp, and this transfer varies with the curing unit used.

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