scholarly journals The mechanics of tessellations – bioinspired strategies for fracture resistance

2016 ◽  
Vol 45 (2) ◽  
pp. 252-267 ◽  
Author(s):  
Peter Fratzl ◽  
Otmar Kolednik ◽  
F. Dieter Fischer ◽  
Mason N. Dean
Keyword(s):  
Fracture Resistance ◽  
Three Dimensional ◽  
Bioinspired Materials

Two- or three-dimensional tiling improves the fracture resistance of natural and bioinspired materials and may even provide additional functionality.

scholarly journals Effect of Reduced Occlusal Thickness with Two Margin Designs on Fracture Resistance of Monolithic Zirconia Crowns

2020 ◽  
Vol 14 (02) ◽  
pp. 245-249
Author(s):  
Haider Hasan Jasim ◽  
Meelad Basil Findakly ◽  
Nada Ali Mahdi ◽  
Mustafa Tariq Mutar
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
Three Dimensional ◽  
Fracture Load ◽  
Anova Test ◽  
Optical Scanner ◽  
Nickel Chromium ◽  
Significant Difference ◽  
Zirconia Crowns ◽  
Monolithic Zirconia

Abstract Objectives The aim of this study was to compare the effects of two margin designs (shoulderless and slight chamfer) with two occlusal thicknesses on fracture resistance and failure mode of the monolithic zirconia crowns. Materials and Methods Forty nickel–chromium dies were duplicated from the previous two prepared teeth using a three-dimensional optical scanner. Nickel–chromium supporting dies were divided into two main groups (n = 20) according to the type of margin design: group A, slight chamfer margin design and group B, shoulderless margin design. These groups were further divided into two subgroups according to the occlusal thicknesses (0.5 and 1 mm). The digital imaging of each die was done using a three-dimensional optical scanner, then zirconia blocks were milled by 5-axis machine. The crowns were cleaned by alcohol, air dried, and cemented by resin cement. Next, the crowns were subjected to 500 hot and cold cycles (30 seconds for each cycle). The samples were subjected to a static load until failure using an electronic universal testing machine and fracture resistance was recorded in Newton (N). Statistical Analysis Data were analyzed using the test of normality (Shapiro–Wilk test) and two-way analysis of variance (ANOVA) test. Results  The highest mean fracture load was recorded by the shoulderless (1 mm occlusal thickness) subgroup (3,992.5 N), followed by shoulderless (0.5 mm occlusal thickness) subgroup (3,244.4 N), and the slight chamfer (1 mm occlusal thickness) subgroup (2,811 N). The lowest mean of fracture load was recorded by slight chamfer (0.5 mm occlusal thickness) subgroup (1,632.9 N). The two-way ANOVA test revealed a significant difference between the four subgroups. Regarding the fracture mode, the slight chamfer subgroups showed a severe fracture of the restoration while the shoulderless subgroups showed a fracture through the midline of the restoration. Conclusion Within the limitation of the comparative study, shoulderless margin design has a more favorable outcome than a slight chamfer design in all thicknesses. Although the restoration with reduced occlusal thickness has lower fracture resistance than 1 mm occlusal thickness, the 0.5 mm restorations still can tolerate occlusal forces.

Three-Dimensional Laser Engraving for Fabrication of Tough Glass-Based Bioinspired Materials

JOM ◽  
2020 ◽  
Vol 72 (4) ◽  
pp. 1487-1497 ◽  
Author(s):  
Ahmed S. Dalaq ◽  
Francois Barthelat
Keyword(s):  
Three Dimensional ◽  
Laser Engraving ◽  
Bioinspired Materials

scholarly journals Bioinspired Materials 2018: Conference Report

Biomimetics ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 4 ◽  
Author(s):  
Marloes Peeters ◽  
Patricia Linton ◽  
Araida Hidalgo-Bastida
Keyword(s):  
Tissue Engineering ◽  
Fuel Cell ◽  
3D Printing ◽  
Three Dimensional ◽  
Conference Report ◽  
Materials Chemistry ◽  
The Third ◽  
Wide Range ◽  
Bioinspired Materials ◽  
Metropolitan University

The Bioinspired Materials conference 2018 was organized for the third time by a team of researchers from Manchester Metropolitan University. This international conference aims to bring together the scientific committee in the fields of biomimetic sensors, bioinspired materials, materials chemistry, three-dimensional (3D) printing, and tissue engineering. The 2018 edition was held at the John Dalton Building of Manchester Metropolitan University, Manchester, UK, and took place on the 10th of October 2018. There were over 60 national and international attendees, with the international attendees participating in a lab tour through the synthetic facilities and Fuel Cell Innovation Centre on the 9th of October. The three conference sessions encompassed a wide range of topics, varying from biomimetic sensors, hydrogels, and biofabrics and bioengineering.

A three-dimensional multilayer graphene web for polymer nanocomposites with exceptional transport properties and fracture resistance

2018 ◽  
Vol 5 (2) ◽  
pp. 275-284 ◽  
Author(s):  
Xi Shen ◽  
Zhenyu Wang ◽  
Ying Wu ◽  
Xu Liu ◽  
Yan-Bing He ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Transport Properties ◽  
Polymer Nanocomposites ◽  
Fracture Resistance ◽  
Three Dimensional ◽  
High Density ◽  
Multilayer Graphene ◽  
Thermal Conductivities

A CVD-grown high-density 3D multilayer graphene web (MGW) is used as the filler for polymer nanocomposites, delivering exceptional electrical and thermal conductivities with outstanding fracture toughness.

Fracture Resistance and Analysis of Stress Distribution of Implant-Supported Single Zirconium Ceramic Coping Combination with Abutments Made of Different Materials

2012 ◽  
Vol 28 (4) ◽  
pp. 394-399 ◽  
Author(s):  
Kadir Firidinoğlu ◽  
Suna Toksavul ◽  
Muhittin Toman ◽  
Mehmet Sarikanat ◽  
İbrahim Nergiz
Keyword(s):  
Finite Elements ◽  
Stress Distribution ◽  
Fracture Resistance ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Test Machine ◽  
Finite Elements Analysis ◽  
Zirconium Ceramic ◽  
Implant Abutment ◽  
Von Mises

The purpose of this study was to compare the fracture resistance and fracture mode of single implant-zirconium coping combinations using zirconium and titanium abutments and to analyze the stress distribution pattern using three-dimensional finite elements analysis. Twenty implants with titanium and zirconium abutments were randomly divided into two groups (n = 10) and into resin blocks. Zirconium copings were cemented onto the abutments. The specimens were loaded with 135° angles to the long axis and the load values at the moment of failure were recorded using a universal test machine. Stress levels were calculated according to the maximum Von Mises criteria. The fracture resistances for titanium and zirconium abutment groups were 525.65 N and 514.05 N, respectively. No significant differences were observed between two groups regarding the fracture resistance levels. The maximum Von Mises equivalent stress concentrated on zirconium copings in both of the groups. Implant-abutment-ZrO2 coping combination has the potential to withstand physiological occlusal forces in the anterior region. Three-dimensional finite elements analysis results of the implant-abutment-ZrO2 coping combination is compatible with the results of fracture resistance.

scholarly journals Stress Distribution, Tooth Remaining Strain, and Fracture Resistance of Endodontically Treated Molars Restored Without or With One or Two Fiberglass Posts And Direct Composite Resin

2017 ◽  
Vol 42 (6) ◽  
pp. 646-657 ◽  
Author(s):  
LM Barcelos ◽  
AA Bicalho ◽  
C Veríssimo ◽  
MP Rodrigues ◽  
CJ Soares
Keyword(s):  
Stress Distribution ◽  
Root Canal ◽  
Fracture Resistance ◽  
Composite Resin ◽  
Three Dimensional ◽  
Fracture Load ◽  
The Other ◽  
Element Analysis ◽  
Tooth Structure ◽  
Fracture Modes

ABSTRACT Objectives: To evaluate the effects of direct composite resin without a post or with one or two fiberglass posts on the restoration of severely compromised endodontically treated molars. Methods and Materials: Forty-five molars with 2 mm of “remaining tooth structure” were divided into three groups: Wfgp, restored with Filtek Z350XT without a fiberglass post; 1fgp, restored with Z350XT with one fiberglass post in the distal root canal; and 2fgp, restored with Z350XT with two fiberglass posts, one in the distal root canal and the other in the mesial-buccal root canal. The teeth were load cycled. Tooth remaining strain was measured using strain gauges (n=10) at two moments: TrSt-100 N, during 100 N occlusal loading, and TrSt-Fr, at fracture load. Fracture resistance was calculated, and fracture mode was classified. The elastic modulus and Vickers hardness were calculated using dynamic indentation (n=5). Stress distribution was analyzed by three-dimensional finite element analysis. Results: The use of two fiberglass posts resulted in lower fracture resistance than was noted in the groups with one fiberglass post and without fiberglass posts. The lingual surface of the remaining tooth had higher strain values than the buccal surface, regardless of the restorative technique and moment of evaluation. The absence of a fiberglass post resulted in significantly higher strain values and more irreparable fracture modes than were noted in the other groups. The use of one fiberglass post had a better strain/fracture resistance ratio. Stresses were concentrated in the occlusal portion of the post and in the furcation region. The presence of one fiberglass post resulted in better stress distribution in the entire distal root dentin, reducing stress on the critical areas. Conclusions: The use of one fiberglass post for restoring molars with direct composite resin resulted in higher fracture resistance than did the use of two fiberglass posts; it also resulted in better tooth remaining strain and stress distribution and more reparable fracture modes than were seen in the group without a fiberglass post.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

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