Dual-gradient structure leads to optimized combination of high fracture resistance and strength-ductility synergy with minimized final catastrophic failure

The objective of this investigation was to correlate the chemical composition of welding rods for gas tungsten arc welding with the fracture resistance and tensile properties of type 347 welds through the systematic tests and microstructural analyses. Five weld metals which differed in contents of carbon, nitrogen and niobium each other and a high δ-ferrite containing weld metal were deposited by the six different welding rods. J-R fracture resistance and tensile properties were evaluated for the type 347 welds. The microstructural examinations were performed to relate key microstructural features to mechanical properties. It was found that the contents of Nb(C,N) precipitates in type 347 welds were determined by the mixed function of carbon and nitrogen and niobium contents in welding rods. The strengths of type 347 welds were in direct proportion to the contents of Nb(C,N) and J-R fracture resistances were inversely proportional to the contents of Nb(C,N). It was concluded that the type 347 weld with high fracture resistance and adequate strength was obtainable by controlling the sum of carbon and nitrogen contents near 0.1wt% and a limitation of the carbon content below 0.04 wt% in welding rod.

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Fracture Resistance of Monolithic Zirconia Crowns in Implant Prostheses in Patients with Bruxism

Materials ◽

10.3390/ma12101623 ◽

2019 ◽

Vol 12 (10) ◽

pp. 1623 ◽

Cited By ~ 3

Author(s):

Ting-Hsun Lan ◽

Chin-Yun Pan ◽

Pao-Hsin Liu ◽

Mitch M. C. Chou

Keyword(s):

Cyclic Loading ◽

Computer Aided Design ◽

Fracture Resistance ◽

Testing Machine ◽

Von Mises Stress ◽

High Fracture ◽

Computer Aided ◽

Zirconia Crowns ◽

Monolithic Zirconia ◽

Von Mises

The aim of this study is to determine the minimum required thickness of a monolithic zirconia crown in the mandibular posterior area for patients with bruxism. Forty-nine full zirconia crowns, with seven different occlusal thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm, were made by using a computer-aided design/computer-aided manufacturing system (CAD/CAM). Seven crowns in each group were subjected to cyclic loading at 800 N and 5 Hz in a servohydraulic testing machine until fracture or completion of 100,000 cycles. Seven finite element models comprising seven different occlusal thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm were simulated using three different loads of vertical 800 N, oblique 10 degrees 800 N, and vertical 800 N + x N torque (x = 10, 50, and 100). The results of cyclic loading tests showed that the fracture resistance of the crown was positively associated with thickness. Specimen breakage differed significantly according to the different thicknesses of the prostheses (p < 0.01). Lowest von Mises stress values were determined for prostheses with a minimal thickness of 1.0 mm in different loading directions and with different forces. Zirconia specimens of 1.0 mm thickness had the lowest stress values and high fracture resistance and under 800 N of loading.

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Polymer composites with dual gradient structure

Macromolecular Symposia ◽

10.1002/masy.19971180151 ◽

1997 ◽

Vol 118 (1) ◽

pp. 389-393 ◽

Cited By ~ 4

Author(s):

Chul Rim Choe ◽

Min Park

Keyword(s):

Polymer Composites ◽

Gradient Structure ◽

Dual Gradient

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The Retention and Fracture Resistance of Two All-ceramic Post and Core Systems in Anterior Endodontically Treated Teeth

Galen Medical Journal ◽

10.31661/gmj.v3i2.113 ◽

2014 ◽

Vol 3 (2) ◽

pp. 95-101

Author(s):

Anahita Safari ◽

Amir Alireza Khaledi ◽

Zeinab Shafiee ◽

Naeeme Rahmani

Keyword(s):

Fracture Resistance ◽

High Fracture Toughness ◽

High Fracture ◽

Endodontically Treated Teeth ◽

Core System ◽

Crosshead Speed ◽

All Ceramic ◽

Post And Core ◽

The Difference ◽

Selection Of

Background: In anterior endodontically treated teeth a better esthetic can be achieved by using all-ceramic post -core restorations instead of metal post systems. Maximum retention and fracture resistance of the post are the criteria upon which selection of a post system is based. The aim of this study was to evaluate the fracture resistance and retention of two all-ceramic post and core systems including IPS Empress 2 post-core system and IPS Empress 2 core connected to Zirconium Cosmopost, and comparing these features among the two groupsMaterial and methods: Eighty extracted maxillary central incisors and canines were divided into two groups of 40 including IPS Empress 2 and zirconium Cosmopost. To evaluate retention, shear force was applied to the cement at the crosshead speed of 0.5 mm/min; force was applied until the post was detached from the canal. To measure the fracture resistance, the samples were loaded at 45-degrees to the horizon at the crosshead speed of 5 mm/min until fracture occurred.Result: The mean fracture strength and standard deviation of zirconium Cosmopost and IPS Empress 2 were 302.10 N (69.922), 151.63 N (48.661), respectively. The difference between groups was significant statistically (P<0.001). The zirconium Cosmoposts had lower retention than IPS Empress2 dowel-core, but the difference between groups was insignificant (p =0.134). Conclusion: Within the limitations of the study, it could be concluded that zirconium Cosmopost system may be a candidate for the restoration of anterior endodontically treated teeth, as the high fracture toughness and propitious esthetic feature.

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Functions with Primal-Dual Gradient Structure and u-Hessians

Applied Optimization - Nonlinear Optimization and Related Topics ◽

10.1007/978-1-4757-3226-9_12 ◽

2000 ◽

pp. 219-233 ◽

Cited By ~ 6

Author(s):

Robert Mifflin ◽

Claudia Sagastizábal

Keyword(s):

Gradient Structure ◽

Primal Dual ◽

Dual Gradient

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Are Metal-Free Monolithic Crowns the Present of Prosthesis? Study of Mechanical Behaviour

Materials ◽

10.3390/ma12223663 ◽

2019 ◽

Vol 12 (22) ◽

pp. 3663 ◽

Cited By ~ 2

Author(s):

Rubén Agustín-Panadero ◽

Raquel León Martínez ◽

María Fernanda Solá-Ruíz ◽

Antonio Fons-Font ◽

Georgina García Engra ◽

...

Keyword(s):

Fracture Resistance ◽

Tetragonal Zirconia ◽

Control Group ◽

High Fracture ◽

Group V ◽

Static Compression ◽

Group I ◽

Monolithic Zirconia ◽

Graphene Nanoparticles

Purpose: To analyze in vitro the mechanical behavior of five types of complete coverage crowns fabricated from different materials. Materials and methods: Seventy-five full coverage crowns were divided into five groups according to material: Group I, metal core with feldspathic ceramic covering (MC- control group); Group II, zirconia core with feldspathic ceramic covering (CZ); Group III, tetragonal monolithic zirconia (TMZ); Group IV, cubic monolithic zirconia (CMZ); Group V, high molecular weight polymethyl methacrylate (PMMAG) doped with graphene nanoparticles. All crowns underwent in vitro fatiguing by dynamic loading in wet conditions to simulate the masticatory forces to which prosthodontic materials are subject in the oral medium. Lastly, fracture resistance was evaluated by static compression testing. Results: The fracture resistance values obtained were as follows: Group MC, 2443.6 ± 238.6 N; Group CZ, 2095.4 ± 329.2 N; Group TMZ, 2494.6 ± 236.6 N; Group CMZ, 1523.6 ± 325.2 N; and Group PMMAG, 1708.9 ± 386.6 N. Group MC presented higher strength with statistically significant differences in comparison with Groups CZ (P = 0.002), CMZ (P < 0.001), and PMMAG (P < 0.001). Weibull distribution showed less probability of cumulative biomechanical failure in Groups MC and TMZ. Conclusions: Metal-ceramic and tetragonal zirconia showed high fracture resistance, while cubic zirconia and PMMA doped with graphene nanoparticles obtained lower values.

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High fracture resistance of carbon fiber treated by electron beam irradiation

Journal of Materials Research ◽

10.1557/jmr.2001.0226 ◽

2001 ◽

Vol 16 (6) ◽

pp. 1632-1635 ◽

Cited By ~ 60

Author(s):

Yoshitake Nishi ◽

Takashi Toriyama ◽

Kazuya Oguri ◽

Akira Tonegawa ◽

Kazuo Takayama

Keyword(s):

Electron Beam ◽

Carbon Fiber ◽

Fracture Resistance ◽

Critical Density ◽

Dangling Bonds ◽

High Fracture ◽

Bending Strain ◽

New Concepts ◽

Irradiation Treatment ◽

Lower Temperature

A crack reduction by electron beam (EB) irradiation treatment for carbon fiber, used without the traditional method of accompanying heat, was developed to modify the mechanical properties at lower temperature. The EB treatment improved the resistance to fracture. Namely, the maximum ratio of fractured samples (maxRf) and the minimum bending strain on fracture (minεf) were defined as simple indicators of fracture resistance and became smaller by the EB treatment. Furthermore, a critical density of dangling bonds for a fracture was suggested and determined for carbon fiber treated by EB irradiation. The EB irradiation to reduce cracking and the determination of the critical density of dangling bonds are new concepts that can be broadly applied in the fields of aerospace and rapid-transit production engineering.

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On $\mathcalVU$-theory for Functions with Primal-Dual Gradient Structure

SIAM Journal on Optimization ◽

10.1137/s1052623499350967 ◽

2000 ◽

Vol 11 (2) ◽

pp. 547-571 ◽

Cited By ~ 31

Author(s):

Robert Mifflin ◽

Claudia Sagastizábal

Keyword(s):

Gradient Structure ◽

Primal Dual ◽

Dual Gradient

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Effect of Angle and Type of Customized Abutment (Castable & Cast-to) on Torque Loss and Fracture Resistance After Cyclic Loading

The Open Dentistry Journal ◽

10.2174/1874210601811120987 ◽

2018 ◽

Vol 12 (1) ◽

pp. 987-994

Author(s):

Moeen Hosseini Shirazi ◽

Maryam Memarian ◽

Marzieh Alikhasi ◽

Somayeh Zeighami

Keyword(s):

Cyclic Loading ◽

Repeated Measures ◽

Fracture Resistance ◽

Testing Machine ◽

Chromium Alloy ◽

Cobalt Chromium ◽

High Fracture ◽

Before And After ◽

Torque Loss ◽

Rotational Freedom

Background: Implant placement with more than 25° angle and use of customized abutments are still challenging in implant dentistry. Also, casting is still the most commonly used method for fabrication of customized abutments. Objective: This study evaluated the effect of angulation and type of abutment (castable and cast-to) on torque loss and fracture resistance after cyclic loading. Methods: Two implants were mounted with 0 and 30° angle on a gypsum model. Castable and Cast-to abutments were casted by cobalt-chromium alloy on each implant (10 samples in 4 groups). Rotational freedom was measured by a video-measuring microscope. The reverse torque values before and after cyclic loading (500,000 cycles) were measured by a digital torque-meter. Abutments were subjected to fracture resistance test in a universal testing machine. Data were analyzed using the Kruskal Wallis, two-way ANOVA and repeated measures tests. Results: Difference between castable and cast-to abutments regarding rotational freedom was not significant. Torque loss in castable abutments was significantly greater than cast-to abutments before and after cyclic loading (P < 0.05). The effect of abutment angle on torque loss before and after cyclic loading was not significant. Conclusion: Irrespective of the abutment angle, torque loss was significantly higher in castable groups. Considering the high fracture resistance, abutment fractures were not clinically an issue.

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Contemporary All-ceramic Systems – Part 2

Acta Medica (Hradec Kralove Czech Republic) ◽

10.14712/18059694.2017.64 ◽

2007 ◽

Vol 50 (2) ◽

pp. 105-107 ◽

Cited By ~ 2

Author(s):

Shriharsha Pilathadka ◽

Dagmar Vahalová

Keyword(s):

Success Rate ◽

Fracture Resistance ◽

Clinical Success ◽

High Strength ◽

Ceramic Materials ◽

In Vivo Studies ◽

High Fracture ◽

All Ceramic

Current all-ceramic materials offer a accepted level of fracture resistance, fit and aesthetics. High fracture resistance recommends it to be a material to support fixed partial denture (FPD) in a stress bearing area with clinical success. This part of the present literature review covers the success rate, selection criteria of all ceramic systems, cementation technique, finishing and polishing. In vitro and in vivo studies of new high strength ceramics were well documented. Data suggest that single crowns in the anterior and posterior region are more predictable than bridges. Well-studied longterm success rate for FPDs are very limited.

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