scholarly journals Biocompatibility of Lithium Disilicate and Zirconium Oxide Ceramics with Different Surface Topographies for Dental Implant Abutments

2021 ◽  
Vol 22 (14) ◽  
pp. 7700
Author(s):  
Susanne Jung ◽  
Marco Maria Moser ◽  
Johannes Kleinheinz ◽  
Arndt Happe
Keyword(s):  
High Strength ◽  
Lithium Disilicate ◽  
Cytotoxic Effects ◽  
Cellular Behavior ◽  
Implant Abutments ◽  
Surface Topographies ◽  
Living Dead ◽  
Level Of Significance ◽  
Dental Applications ◽  
First Time

Gingivafibroblasts were cultured on lithium disilicate, on zirconia dioxide, and on titanium with two different surface roughnesses (0.2 µm and 0.07 µm); Proliferation (MTT), Living/Dead staining, cytotoxicity (LDH), proliferation (FGF2), and inflammation (TNFα) were analyzed after 1 day and 21 days. Furthermore, alteration in cell morphology (SEM) was analyzed. The statistical analysis was performed by a Kruskal–Wallis test. The level of significance was set at p < 0.05. There were no distinct differences in cellular behavior between the tested roughness. There were slight differences between tested materials. Cells grown on zirconia dioxide showed higher cytotoxic effects. Cells grown on lithium disilicate showed less expression of TNFα compared to those grown on zirconia dioxide or titanium. These effects persisted only during the first time span. The results indicate that the two tested high-strength ceramics and surface properties are biologically suitable for transmucosal implant components. The findings may help clinicians to choose the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical dental applications.

Crystal Phase Formation and Mechanical Properties of Lithium Disilicate Glass-Ceramics for Dental Restoration

2010 ◽  
Vol 177 ◽  
pp. 447-450 ◽  
Author(s):  
Xin Zhang ◽  
Yi Wen Hu ◽  
Yin Wu ◽  
Wen Jie Si
Keyword(s):  
Mechanical Properties ◽  
Phase Formation ◽  
Glass Ceramics ◽  
High Strength ◽  
Lithium Disilicate ◽  
Sem Analysis ◽  
Dental Restoration ◽  
Bending Test ◽  
Crystal Phase ◽  
High Temperature Xrd

The purpose of this study was to evaluate the crystal phase formation behavior and its influence on the mechanical properties of LiO2-SiO2-P2O5 glass-ceramics system. High temperature XRD was used to analyze the crystal phase formation in situ. The crystalline phases in the material both before and after heat-treatment were also analyzed. The flexural strength was measured by three-point bending test according to ISO 6872:2008(E). The SEM analysis showed that the high strength of the glass-ceramics is attributed to the continuous interlocking microstructure with fine lithium disilicate crystallines.

Structure and crystallization of SiO2and B2O3doped lithium disilicate glasses from theory and experiment

2017 ◽  
Vol 19 (37) ◽  
pp. 25298-25308
Author(s):  
Andreas Erlebach ◽  
Katrin Thieme ◽  
Marek Sierka ◽  
Christian Rüssel
Keyword(s):  
Solid Solutions ◽  
Lithium Disilicate ◽  
First Time ◽  
Theory And Experiment

Solid solutions of SiO2and B2O3in Li2O·2SiO2are synthesized and characterized for the first time by calculations and experiments.

scholarly journals A pilot trial on lithium disilicate partial crowns using a novel prosthodontic Functional Index for Teeth (FIT)

2019 ◽  
Author(s):  
Edoardo Ferrari Cagidiaco ◽  
Simone Grandini ◽  
Cecilia Goracci ◽  
Tim Joda
Keyword(s):  
Clinical Performance ◽  
Pilot Trial ◽  
Lithium Disilicate ◽  
Bone Biology ◽  
Functional Index ◽  
Posterior Teeth ◽  
Significant Difference ◽  
Group 2 ◽  
Technical Complication ◽  
Level Of Significance

Abstract Background Lithium disilicate is now a well accepted material for indirect restorations. The aim of this trial was to evaluate two lithium disilicate systems using a novel prosthodontic Functional Index for Teeth (FIT).Methods Partial adhesive crowns on natural abutment posterior teeth were made on sixty patients (clinicaltrial.gov # NCT 01835821). Patients were divided into two groups: Group 1 e.max press (Ivoclar), Group 2 LiSi press (GC Co.). The restorations were followed-up for 3 years. The FIT is composed of seven variables (Interproximal, Occlusion, Design, Mucosa, Bone, Biology and Margins), each of them to be evaluated using a 0-1-2 scoring scheme. The Mann-Whitney ‘U’ test was applied. The level of significance was set at p<0,05.Results Survival rate was 100%, without any biological or technical complication. No statistically significant difference emerged between the two groups in any of the assessed variables (p>0.05).Conclusions The results showed that it is possible to evaluate the clinical performance of partial crowns using FIT. The FIT proved to be an effective tool to foresee the possible risk of failures and to monitor the performance of the restorations at each recall. The two lithium dislocate materials showed same results after 3 years of clinical service.

scholarly journals Nitrogen-phosphate Fertilizers Based on Activation of Phosphorite Powder with Partially Ammoniated Mix of Phosphoric and Sulphuric Acids

2020 ◽  
pp. 1-10
Author(s):  
A. A. Rasulov ◽  
Sh. S. Namazov ◽  
B. E. Sultonov
Keyword(s):  
Citric Acid ◽  
Gross Domestic Product ◽  
Optimal Condition ◽  
Ammonium Sulphate ◽  
Weight Ratio ◽  
High Strength ◽  
Technological Parameters ◽  
Phosphate Fertilizers ◽  
First Time ◽  
Phosphoric Acids

In this article obtaining complex nitrogen-phosphate fertilizers based on activation of phosphorite powder with partially ammoniated mix of phosphoric and sulphuric acids have been studied. In order to reduce the foaming of the process, for the first time a partially ammoniated mix of acids was used. The optimal technological parameters for activation phosphorite powder with partially neutralized mixes of sulphuric and phosphoric acids are the followings: the mix of sulphuric and phosphoric acids with a ratio of SО3:Р2О5 = 1.2; рН of acids – 2.5; weight ratio of ammonium sulphate-phosphate slurry towards phosphorite powder is 100 : 20; temperature is 60°С; duration is 30 min.  The composition nitrogen-phosphate fertilizers obtained in optimal condition contains (wt., %): N – 11.55; Р2О5total -24.61; Р2О5acceptable by citric acid -21.66; Р2О5 acceptable by EDTA -20.24; Р2О5water-soluble  -13.02; CaOtotal -13.59; СаОacceptable by citric acid -11.43. In that condition, granulated products of nitrogen-phosphate can be produced with high strength. The advantage of offered promising technology concludes in reduction two times expenditure of the most expensive ammonia in comparison with ammonium sulphate production and an increase in gross domestic product.

scholarly journals The nanostructuring of ultra-high-molecular-weight polyethylene in thermal and mechanical fields as revealed by DSC

2021 ◽  
Vol 2103 (1) ◽  
pp. 012095
Author(s):  
L P Myasnikova ◽  
A K Borisov ◽  
Yu M Boiko ◽  
A P Borsenko ◽  
V F Drobot’ko ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Melting Temperature ◽  
Mechanical Characteristics ◽  
Thickness Distribution ◽  
High Strength ◽  
High Modulus ◽  
Know How ◽  
First Time ◽  
Ultra High Molecular Weight

Abstract The ultra-high-molecular-weight polyethylene reactor powders are widely used for the actively developing solvent-free method for producing high-strength high-modulus PE filaments, which includes the compaction and sintering of a powder followed by orientational hardening. To find an appropriate regime of the technological process, it is important to know how the nanostructure changes when transforming from a powder to a precursor for hardening. Nanocrystalline lamellae are characteristics of the powder structure. For the first time, the DSC technique was used to follow changes in the thickness distribution of lamellae in ultra-high-molecular-weight polyethylene reactor powder on its way to a precursor for orientation hardening. It was found that the percentage of thick (>15 nm) and thin (10 nm) lamellae in compacted samples and those sintered at temperatures lower than the melting temperature of PE (140°C) remains nearly the same. However, significant changes in the content of lamellae of different thicknesses were observed in the samples sintered at 145°C with subsequent cooling under different conditions. The influence of the lamellae thickness distribution in precursors on the mechanical characteristics of oriented filaments was discussed.

scholarly journals Effects of Calcium Phosphate Nanoparticles on Ca-PO4 Composite

2007 ◽  
Vol 86 (4) ◽  
pp. 378-383 ◽  
Author(s):  
H.H.K. Xu ◽  
M.D. Weir ◽  
L. Sun ◽  
S. Takagi ◽  
L.C. Chow
Keyword(s):  
Volume Fraction ◽  
High Strength ◽  
Nano Particles ◽  
Nano Silica ◽  
Ion Release ◽  
Mass Fractions ◽  
Calcium Phosphate Nanoparticles ◽  
Filler Mass ◽  
First Time ◽  
Filler Level

Nano-particles of dicalcium phosphate anhydrous (DCPA) were synthesized for the first time. The objectives of this study were to incorporate DCPA nano-particles into resin for Ca-PO4 release to combat dental caries, and to investigate the filler level effects. Nano-DCPA and nano-silica-fused silicon nitride whiskers at a 1:1 ratio were used at filler mass fractions of 0–75%. The flexural strengths in MPa (mean ± SD; n = 6) of DCPA-whisker composites ranged from (106 ± 39) at 0% fillers to (114 ± 23) at 75% fillers, similar to (112 ± 22) of a non-releasing composite (TPH) (p > 0.1). The composite with 75% fillers in a NaCl solution (133 mmol/L, pH = 7.4, 37°C) yielded a Ca concentration of (0.65 ± 0.02) mmol/L and PO4 of (2.29 ± 0.07) mmol/L. Relationships were established between ion-release and DCPA volume fraction VDCPA: Ca = 4.46 VDCPA1.6, and = 66.9 VDCPA2.6. Nano-DCPA-whisker PO4 composites had high strength and released high levels of Ca-PO4 requisite for remineralization. These new nano-composites could provide the needed combination of stress-bearing and caries-inhibiting capabilities.

scholarly journals Resveratrol Targets Sphingolipid Metabolism to Induce Growth Inhibition in FLT3 ITD Acute Myeloid Leukemia

Proceedings ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 4
Author(s):  
Ersöz ◽  
Adan
Keyword(s):  
Growth Inhibition ◽  
Cell Fate ◽  
De Novo ◽  
Therapeutic Potential ◽  
Annexin V ◽  
Sphingolipid Metabolism ◽  
Ceramide Synthase ◽  
Cytotoxic Effects ◽  
Sphingosine 1 Phosphate ◽  
First Time

Sphingolipids are important signaling lipids which play crucial roles to determine the cell fate. Ceramide, apoptotic central molecule of sphingolipid metabolism, which is produced through de novo pathway by serine palmitoyl transferase (SPT) and can be converted to antiapoptotic sphingosine-1-phosphate (S1P) and glucosyl ceramide (GC) by sphingosine kinase (SK) and glucosyl ceramide synthase (GCS), respectively. It is aimed to investigate therapeutic potential of resveratrol on FLT3-ITD (Internal Tandem Duplication) AML cells and to identify potential mechanism behind resveratrol-mediated growth inhibition by targeting of ceramide metabolism. The cytotoxic effects of resveratrol, SPT inhibitor (myricoin), SK-1 inhibitor (SKI II), GCS inhibitor (PDMP), resveratrol: SPT inhibitor, resveratrol: SK-1 inhibitor and resveratrol: GCS inhibitor combinations on MOLM-13 and MV4-11 FLT3 ITD AML cells were investigated by cell proliferation assay. Apoptosis was evaluated by annexin V/PI double staining. There were synergistic cytotoxic effects of resveratrol with co-administration of SPT inhibitor, SK-1 inhibitor and GCS inhibitor and apoptosis was synergistically induced for resveratrol and its combinations. This preliminary data showed for the first time that resveratrol might inhibit the growth of FLT3 ITD AML cells through targeting ceramide metabolism.

Effect of Sintering Conditions on Mechanical and Optical Properties of 3Y-TZP Dental Ceramic

2014 ◽  
Vol 608 ◽  
pp. 181-186
Author(s):  
Kannigar Dateraksa ◽  
Sukunthakan Ngernbamrung ◽  
Ryan C. McCuiston
Keyword(s):  
Fracture Toughness ◽  
Optical Properties ◽  
High Strength ◽  
Dental Ceramics ◽  
Heating Rates ◽  
Microstructural Characteristics ◽  
One Step ◽  
Sintering Conditions ◽  
Dental Applications ◽  
Spray Dried

The use of zirconia dental ceramics has grown in recent years due to improvements in esthetics and biocompatibility. Zirconia is used in dental applications for its high strength and fracture toughness. In this research, the influence of sintering conditions on the strength and optical properties of zirconia was investigated. Spray dried granules of 3Y-TZP zirconia were die pressed into disc-shaped samples and cold isostatic pressed at 250 MPa. Sintering was conducted using either one step sintering at 1500 oC or two-step sintering, with pre-sintering at 1200 oC and final sintering at 1500 oC. Heating rates of 2 and 10 oC/min were used. The biaxial flexural strength, fracture toughness, density, microstructural characteristics and optical properties of the sintered samples were determined. It was found that the sintering conditions did appear to influence the mechanical and optical properties. The sintering conditions had no significant effect on the density. It was concluded that for the sintering conditions examined, the two-step sintering with a heating rate of 2 oC/min produced the best average mechanical and optical properties of 3Y-TZP zirconia.

Geotechnical characteristics of large rapid rock slides

2010 ◽  
Vol 47 (1) ◽  
pp. 116-132 ◽  
Author(s):  
James Glastonbury ◽  
Robin Fell
Keyword(s):  
High Strength ◽  
Significant Loss ◽  
Slide Mass ◽  
Geotechnical Characteristics ◽  
Lateral Margins ◽  
Internal Deformation ◽  
Strength Rock ◽  
First Time ◽  
Loss Of Strength ◽  
Rock Slides

Based on the analysis of 51 case studies of large rapid rock slides, for a landslide to travel rapidly after failure there has to be a significant loss of strength on the basal surface of rupture, lateral margins, and (or) internally within the slide mass, or the factor of safety has to be maintained below 1.0 after failure by high groundwater pressures. Internally sheared compound slides and translational slides may all travel rapidly depending on their detailed geotechnical and geometric characteristics. The characteristics of these landslides that suggest an increased likelihood of rapid failure have been identified. All the rapid rock slides examined in this study involved relatively high-strength rock masses. Most cases were considered to be first-time landslides, largely involving brittleness on the basal rupture surface. However, there were some cases considered to be reactivated or active landslides on pre-sheared rupture surfaces. For this latter group, the loss of strength leading to rapid landsliding was associated with brittle internal deformation or lateral margins.

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