scholarly journals External gap progression after cyclic fatigue of adhesive overlays and crowns made with high translucency zirconia or lithium silicate

2021 ◽  
Author(s):  
Andrea Baldi ◽  
Allegra Comba ◽  
Giorgio Ferrero ◽  
Edoardo Italia ◽  
Riccardo Michelotto Tempesta ◽  
...  
Keyword(s):  
Cyclic Fatigue ◽  
Lithium Silicate

scholarly journals External Marginal Gap Variation and Residual Fracture Resistance of Composite and Lithium-Silicate CAD/CAM Overlays after Cyclic Fatigue over Endodontically-Treated Molars

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 3002
Author(s):  
Andrea Baldi ◽  
Allegra Comba ◽  
Riccardo Michelotto Tempesta ◽  
Massimo Carossa ◽  
Gabriel Kalil Rocha Pereira ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Composite Resin ◽  
Cyclic Fatigue ◽  
Lithium Silicate ◽  
Restorative Material ◽  
Micro Ct ◽  
Fiber Post ◽  
Marginal Gap ◽  
The Core ◽  
Interfacial Gap

The purpose of this in vitro study was to evaluate the external marginal gap variation with a 3D quantitative method and the residual fracture resistance after cyclic fatigue in endodontically treated molars restored with overlays of different materials, with and without fiber posts-supported buildups. Forty-eight human maxillary molars were selected, endodontically treated, prepared with standardized MOD cavities and randomly allocated into 6 study groups considering the “core strategy” (build-up with composite resin; build-up with composite resin supported by a fiber post); and the “restorative material” of the indirect adhesive overlay (GrandioBlocks, Voco; Cerasmart, GC; CeltraDuo, Dentsply). All procedures were executed according with manufacturers guidelines. Micro-CT analysis prior and after cyclic fatigue were executed, followed by scanning electron microscope analysis and fracture resistance test. The Two-Way ANOVA analysis showed that interfacial gap progression was significantly influenced by the “core strategy” (p < 0.01) but not of “restorative material” (p = 0.59). Concerning fracture resistance, “restorative material” was statistically significant (p < 0.01), while “core strategy” (p = 0.63) and the interaction (p = 0.84) were not. In conclusion, the fiber post presence within the build-up promoted a lower interfacial gap opening after fatigue, evaluated through micro-CT scans. In terms of fracture resistance, teeth restored with Cerasmart and Celtra Duo were statistically similar, but superior to GrandioBlocks.

NUCLEAR SPIN-LATTICE RELAXATION IN A LITHIUM-SILICATE GLASS

1982 ◽  
Vol 43 (C9) ◽  
pp. C9-143-C9-147 ◽  
Author(s):  
P. Heitjans ◽  
B. Bader ◽  
K. Dörr ◽  
H. J. Stöckman ◽  
G. Kiese ◽  
...  
Keyword(s):  
Silicate Glass ◽  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Lithium Silicate ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation ◽  
Lithium Silicate Glass

Cyclic fatigue comparison among endodontic instruments with similar cross section and different surface coating

2019 ◽  
Vol 68 (2) ◽  
Author(s):  
Eugenio Pedullà ◽  
Gianluca Plotino ◽  
Mauro Scibilia ◽  
Nicola M. Grande ◽  
Daniele De Santis ◽  
...  
Keyword(s):  
Cross Section ◽  
Surface Coating ◽  
Cyclic Fatigue

Chairside CAD-CAM milling materials optical properties: feldspathic versus lithium silicate

2018 ◽  
Vol 19 (4) ◽  
pp. 230-233
Author(s):  
Adrian Mihai Varvară ◽  
◽  
Ralph Boutros ◽  
Anca Ştefania Mesaroş ◽  
Elena Bianca Varvară ◽  
...  
Keyword(s):  
Optical Properties ◽  
Lithium Silicate ◽  
Cad Cam

Degree of Conversion of Light Cured Resin Cements Polymerized under Two Thicknesses of Different Lithium Silicate Ceramics

2020 ◽  
Author(s):  
Mohamed Abdel Rahman Maraghy
Keyword(s):  
Degree Of Polymerization ◽  
Resin Cement ◽  
Lithium Silicate ◽  
Resin Cements ◽  
Ceramic Disc ◽  
Ceramic Disk ◽  
The Difference ◽  
Light Cure Unit ◽  
Glass Slab ◽  
Finger Pressure

Objective: To show the consequence of two thicknesses of ceramic on the polymerization of resin cement light cured when three different lithium silicate ceramics were used. Materials and Methods: 42 ceramic slices were prepared from three types of ceramics, Emax CAD, Celtra Duo CAD and Vita suprinity CAD (n=14). They were further divided into two subgroups according to thicknesses into sub group thickness 0.5mm and sub group thickness 1mm (n=7). Teflon moulds were fabricated with specific dimensions, where the ceramic disc was placed followed by light cured resin cement Bisco choice 2 veneer and a glass slab with finger pressure applied. Curing with Ascent® PX LED light cure unit for 20 seconds took place, where the tip placed over the ceramic sample directly. Cement film was then separated from the ceramic disk and subjected to analysis by Fourier Transform Infrared Spectroscope. Uncured cement samples were also subjected to analysis. Results: Celtra DUO CAD ceramic showed higher degree of polymerization that of Emax and Vita suprinity while the difference between Emax and Suprinity on the degree of polymerization was not significant. Also, ceramic thicknesses had a significant effect on the degree of polymerization of the resin cement. Conclusion: Thickness of ceramics up to 1mm affects the polymerization of resin cement significantly.

scholarly journals Effect of synchronous irrigation on cyclic fatigue of nickel-titanium instrument in the dynamic and static models

2021 ◽  
Vol 19 ◽  
pp. 228080002098740
Author(s):  
Haiyun Liu ◽  
Yanfeng Li ◽  
Guangquan Chai ◽  
Yuan Lv ◽  
Changjian Li ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Flow Rate ◽  
Dynamic Control ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Control Group ◽  
Time To Failure ◽  
Dynamic Tests ◽  
Significant Difference ◽  
Experimental Group

Objective: To evaluate the effect of synchronous water irrigation on the fatigue resistance of nickel-titanium instrument. Methods: A standardized cyclic fatigue test models were established, and five types of nickel-titanium instruments (PTU F1, WO, WOG, RE, and M3) were applied. Each instrument was randomly divided into two groups ( N = 12). There was synchronous water irrigation in the experimental group, and no water irrigation in the control group. Besides, ProTaper Universal F1 was randomly divided into 10 groups ( N = 20). In the static group, nickel-titanium instruments were divided into one control group (no irrigation, N = 20) and six experimental group (irrigation, N = 20) based on different flow rate, angle and position; while in the dynamic group, instruments were divided into one control group (no irrigation, N = 20) and two experimental group (irrigation, N = 20) based on different flow rate. The rotation time (Time to Failure, TtF) of instruments was recorded and analyzed. Results: According to the static experiments, the TtF of instruments in all experimental groups was significantly higher than that in the static control group. Besides, the dynamic tests of PTU F1 showed that the TtF in the experimental group was significantly higher than that in the dynamic control group. Compared with control group, the TtF in the experimental groups increased by at least about 30% and up to 160%. The static and dynamic tests of PTU F1 showed that the TtF of nickel-titanium instrument in all experimental groups was significantly higher than that in the control group. However, there was no significant difference between any two experimental groups. Conclusion: Regardless of dynamic or static model, TtF with irrigation was longer than that with non-irrigation, indicating that synchronous irrigation can increase the fatigue resistance of nickel-titanium instrument. However, different irrigation conditions may have the same effect on the fatigue resistance.

Corrosion susceptibility comparison of EUROFER steel in contact two lithium silicate breeders

2014 ◽  
Vol 89 (7-8) ◽  
pp. 1436-1439 ◽  
Author(s):  
T. Hernández ◽  
P. Fernández
Keyword(s):  
Lithium Silicate ◽  
Corrosion Susceptibility

scholarly journals The Effects of Sterilization Procedures on the Cutting Efficiency of Endodontic Instruments: A Systematic Review and Network Meta-Analysis

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1559
Author(s):  
Mario Dioguardi ◽  
Enrica Laneve ◽  
Michele Di Cosola ◽  
Angela Pia Cazzolla ◽  
Diego Sovereto ◽  
...  
Keyword(s):  
Systematic Review ◽  
Selection Process ◽  
Meta Analysis ◽  
Indirect Comparison ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Cyclic Fatigue ◽  
P Value ◽  
Cutting Efficiency ◽  
Dental Instruments

Sterilization processes guarantee the sterility of dental instruments but can negatively affect instrument features by altering their physical and mechanical properties. The endodontic instrumentation can undergo a series of alterations, ranging from corrosion to variation in the cutting angle and then changes in the torsional properties and torsional fatigue resistance. This systematic literature review and meta-analysis aims to investigate alterations to the cutting efficiency of endodontic instruments that are induced by procedures for their disinfection and sterilization. Methodologies adopted for this investigation follow the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. The following were used as search terms on PubMed and Scopus: “endodontic sterilization”, “endodontic autoclave”, “cyclic fatigue”, “torsional”, “cutting efficiency”, “sterilization”, “surface characteristics”, and “corrosion”. At the end of the selection process, 36 articles were identified, and seven of them are included in this systematic review. The results of a meta-analysis conducted for the use of 10 autoclaving cycles shows a standardized mean difference (SMD) of 0.80 with a p-value equal to 0.04 with respect to effect on cutting efficiency. The network meta-analysis, through direct and indirect comparison between the different autoclave cycles (0, 1, 5, 10, and 15 cycles), revealed that treatment involving 15 autoclave cycles produced the most robust results in terms of having the greatest effects in terms of altered cutting efficiency with a probability of 57.7% and a SUCRA (surface under the cumulative ranking) of 80%. The alterations in the effects on cutting efficiency appear to be triggered after five cycles of sterilization by heat (autoclave). In conclusion, the meta-analysis of the data indicates that the autoclave sterilization protocol must not be repeated more than five times to preserve cutting efficiency. Within the limitations of this review, we can therefore establish that sterilization by autoclaving alone results in steel and NiTi instruments becoming less efficient in cutting after five cycles, as measured by a reduction in cutting efficiency.

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