Read by QxMD icon Read

Cyclic Fatigue

Maximiliane Amelie Schlenz, Alexander Schmidt, Peter Rehmann, Bernd Wöstmann
PURPOSE: To analyse fatigue damage of monolithic computer-aided-designed/computer-aided-manufactured (CAD/CAM)-materials after loading with high masticatory forces in standardized posterior crowns in a mouth-motion-simulator. METHODS: For manufacturing of test specimens (5 groups, 16 specimens each), two corresponding Standard-Tessellation-Language-(STL)-data-sets (one for the teeth and one for the crowns) were designed. The teeth were CAD/CAM-milled of human third molars and the crowns of three different CAD/CAM composite blocks (Lava Ultimate,'LU'; Brilliant Crios'BC'; Cerasmart,'CS'), one polymer-infiltrated-ceramic network (Vita Enamic,'VE') and a control group of lithium disilicate ceramics (IPS e...
March 13, 2019: Journal of Prosthodontic Research
Roberto Sorrentino, Chiara Ottavia Navarra, Roberto Di Lenarda, Lorenzo Breschi, Fernando Zarone, Milena Cadenaro, Gianrico Spagnuolo
OBJECTIVES: Stresses produced during the fabrication of copings and by chewing activity can induce a tetragonal-to-monoclinic (t⁻m) transformation of zirconia. As a consequence, in the m-phase, the material is not able to hinder possible cracks by the favorable mechanism known as "transformation toughening". This study aimed at evaluating if different marginal preparations of zirconia copings can cause a premature phase transformation immediately after manufacturing milling and after chewing simulation...
March 14, 2019: Materials
D E Betancourt, P A Baldion, J E Castellanos
Several studies have shown that the dentin-resin interface is unstable due to poor infiltration of resin monomers into the demineralized dentin matrix. This phenomenon is related to the incomplete infiltration of the adhesive system into the network of exposed collagen fibrils, mainly due to the difficulty of displacement and subsequent replacement of trapped water between interfibrillar spaces, avoiding adequate hybridization within the network of collagen fibrils. Thus, unprotected fibrils are exposed to undergo denaturation and are susceptible to cyclic fatigue rupture after being subjected to repetitive loads during function...
2019: International Journal of Biomaterials
Eugenio Pedullà, Emanuele Ambu, Fabio Rovai, Seok-Woo Chang, Federico Campedelli, Giacomo Corsentino, Silvia Rapisarda, Giusy R M La Rosa, Simone Grandini
AIM: The aim of the present study was to evaluate the resistance to cyclic fatigue of heat-treated single files used in proper or in reciprocating optimum torque reverse motions. METHODS: Ninety-six HyFlex electrical discharge machining (EDM), Reciproc R25 (Rec), WaveOne Primary (WO), and WaveOne Gold (WOG) Primary were used. Resistance to cyclic fatigue was determined by recording time to fracture in a stainless steel artificial canal. Differential scanning calorimetric analysis was performed...
March 7, 2019: Journal of Investigative and Clinical Dentistry
Sara A Keller, Sebastian Valet, Ann Martens, Bernhard Weisse, Anton E Fürst, Jan M Kümmerle
OBJECTIVE:  The aim of this study was to evaluate cyclic fatigue behaviour of a new pin with a thread run-out design in comparison with three other types of pins commonly used for equine transfixation pin casting. MATERIALS AND METHODS:  Twenty-four pairs of equine cadaveric third metacarpal bones (MC3) equipped with one transfixation pin placed horizontally in the distal metaphysis were tested using a simplified model, mimicking the biomechanical situation of equine transfixation pin casting...
March 7, 2019: Veterinary and Comparative Orthopaedics and Traumatology: V.C.O.T
Ibrohim Rustamov, Gaolong Zhang, Margarita Skotnikova, Yuming Wang, Zixi Wang
Frictional and fretting wear behaviors of Inconel X-750 alloy against GCr15 steel ball were investigated in dry contact condition with ∼60% air humidity. Fretting tests were run at the high frequency tribosystem SRV 4 in room temperature and ball-on-flat contact configuration were adopted with the relative oscillatory motion of small displacement amplitude (40  μ m). Sliding regimes, wear volumes, frictional properties, and material damage mechanisms were studied with regard to different normal loading and test durations...
April 2019: Journal of Tribology
Michael C Aynardi, Kaitlin Saloky, Evan P Roush, Paul Juliano, Gregory S Lewis
BACKGROUND: The structural importance of the spring ligament complex in arch stability has been described. Furthermore, the pathology of this complex is often noted in patients with posterior tibial tendon dysfunction. The purpose of this biomechanical study was to evaluate spring ligament repair alone versus augmentation with the FiberTape device in a cadaveric flatfoot model. METHODS: Eight paired, below-the-knee, cadaveric specimens underwent flatfoot creation and reconstruction...
March 1, 2019: Foot & Ankle International
Afnan Kashkari, Burak Yilmaz, William A Brantley, Scott R Schricker, William M Johnston
PURPOSE: The aim of this study was to compare the integrity of zirconia, lithium disilicate, and zirconia-reinforced lithium silicate CAD-CAM crowns after being subjected to cyclic loading and then subjected to static loading until fracture. MATERIAL AND METHODS: Zirconia (Zirkonzahn), lithium disilicate (LDS, Ivoclar Vivadent AG), and zirconia-reinforced lithium silicate glass ceramic (ZLS) (Vita Suprinity, Vita Zahnfabrik) monolithic crowns were milled (n = 6)...
February 28, 2019: Journal of Esthetic and Restorative Dentistry
Cambre N Kelly, Nathan T Evans, Cameron W Irvin, Savita C Chapman, Ken Gall, David L Safranski
Additive manufacturing (3D printing) is emerging as a key manufacturing technique in medical devices. Selective laser melted (SLM) Ti-6Al-4V implants with interconnected porosity have become widespread in orthopedic applications where porous structures encourage bony ingrowth and the stiffness of the implant can be tuned to reduce stress shielding. The SLM technique allows high resolution control over design, including the ability to introduce porosity with spatial variations in pore size, shape, and connectivity...
May 2019: Materials Science & Engineering. C, Materials for Biological Applications
Michelle Paulino Sousa, João Paulo Mendes Tribst, Amanda Maria de Oliveira Dal Piva, Alexandre Luiz Souto Borges, Sérgio de Oliveira, Paulo César da Cruz
Because the main complication of implant-supported prostheses is torque loosening and/or fixation screw fracture, the goal of this study was to evaluate the torque before and after fatigue (screw placement and removal, respectively), single load-to-failure (compression test), and stress concentration of straight and angled abutments. Eighty implants were included in polyurethane cylinders. Half of the implants received straight abutments (group S, n = 40) and the other half received angled abutments (group A, n = 40)...
March 2019: International Journal of Periodontics & Restorative Dentistry
Gang Li, Zhiguang Qiu, Yan Wang, Ying Hong, Yongbiao Wan, Jianming Zhang, Junlong Yang, Zhigang Wu, Wei Hong, Chuan Fei Guo
Skin-like electronics ask for materials that are conducting, soft, intrinsically stretchable and highly robust. However, electronic devices often consist of multilayers, and the failure of the electronic devices mostly starts from the debonding of the layers due to poor interfacial adhesion and large mechanical mismatch. Herein, we introduce a fully organic and intrinsically stretchable electrode that achieves high robustness by grafting the substrate to improve the interfacial adhesion, and by introducing deep folds and wrinkles to improve the stretchability...
February 20, 2019: ACS Applied Materials & Interfaces
Joanne Y Zhang, Paul Tornetta, Bob Jones, Yanming Zheng, Andy Whitten, Jacob Cartner, William M Ricci
OBJECTIVES: To evaluate the effect of locking hole inserts (LHIs) and their insertion torque on locking plate fatigue life. METHODS: Eighteen standard 3.5-mm locking plates were instrumented with LHIs (Smith & Nephew, Memphis, TN) of 1.70 or 3.96 Nm insertion torque, or without LHIs, whereas eleven 4.5-mm locking plates were instrumented with LHIs at 3.96 Nm insertion torque or without LHIs. Plates were cyclically loaded to failure (ie, plate fracture) in four-point bending...
March 2019: Journal of Orthopaedic Trauma
Donald L Kellis, Christopher Sarter, Brittany L Cannon, Paul H Davis, Elton Graugnard, Jeunghoon Lee, Ryan D Pensack, Theresa Kolmar, Andres Jäschke, Bernard Yurke, William B Knowlton
The excitonic circuitry found in photosynthetic organisms suggests an alternative to electronic circuits, but the assembly of optically active molecules to fabricate even simple excitonic devices has been hampered by the limited availability of suitable molecular scale assembly technologies. Here we have designed and operated a hybrid all-optical excitonic switch comprised of donor/acceptor chromophores and photochromic nucleotide modulators assembled with nanometer scale precision using DNA nanotechnology...
February 13, 2019: ACS Nano
Shaoting Lin, Xinyue Liu, Ji Liu, Hyunwoo Yuk, Hyun-Chae Loh, German A Parada, Charles Settens, Jake Song, Admir Masic, Gareth H McKinley, Xuanhe Zhao
The emerging applications of hydrogels in devices and machines require hydrogels to maintain robustness under cyclic mechanical loads. Whereas hydrogels have been made tough to resist fracture under a single cycle of mechanical load, these toughened gels still suffer from fatigue fracture under multiple cycles of loads. The reported fatigue threshold for synthetic hydrogels is on the order of 1 to 100 J/m2 . We propose that designing anti-fatigue-fracture hydrogels requires making the fatigue crack encounter and fracture objects with energies per unit area much higher than that for fracturing a single layer of polymer chains...
January 2019: Science Advances
V A Mergulhão, L S de Mendonça, M S de Albuquerque, R Braz
PURPOSE: The purpose of this in vitro study was to evaluate the resistance and patterns of fracture of endodontically treated maxillary premolars (ETPs) restored with different methods. METHODS AND MATERIALS: Mesio-occluso-distal cavities were prepared in 50 extracted caries-free human maxillary premolars after endodontic treatment. The teeth were divided into five groups (n=10), according to the restorative method. G1: intact teeth (control group); G2: conventional composite resin; G3: conventional composite resin with a horizontal glass fiber post inserted between buccal and palatal walls; G4: bulk-fill flowable and bulk-fill restorative composites; and G5: ceramic inlay...
January 2019: Operative Dentistry
Ahmet Keles, Emel Uzunoglu Ozyurek, Mehmet Ozgur Uyanik, Emre Nagas
INTRODUCTION: The aim of this study was to evaluate the effect of different temperatures of sodium hypochlorite (NaOCl) on the cyclic fatigue resistance of the heat-treated file systems. METHODS: The cyclic fatigue resistance of Reciproc 25 (VDW Dental, Munich, Germany), Reciproc Blue R25 (VDW), WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland), WaveOne Gold Primary (Dentsply Maillefer), and One Shape (25.06; Micro Mega, Besançon, France) was tested in the following conditions: control (no immersion), immersion in distilled water (DW) at 37°C ± 1°C, immersion in DW at 60°C ± 1°C, immersion in NaOCl at 37°C ± 1°C, and immersion in NaOCl at 60°C ± 1°C...
February 2019: Journal of Endodontics
Joo-Yeong Lee, Sang Won Kwak, Jung-Hong Ha, Ibrahim H Abu-Tahun, Hyeon-Cheol Kim
INTRODUCTION: The aim of this study was to compare the cyclic fatigue, torsional resistance, and bending stiffness of single-file glide path preparation nickel-titanium instruments. METHODS: ProGlider (#16/progressive taper; Dentsply Sirona, Ballaigues, Switzerland), One G (#14/.03; Micro-Mega, Besancon, France), and EdgeGlidePath (#16/progressive taper; Edge Endo, Albuquerque, NM) were tested. For the bending stiffness test, the instrument was bent to a 45° angle along the main axis while 3 mm of the tip was secured...
February 2019: Journal of Endodontics
D Melo, A Completo, A Nascimento, F Fonseca
BACKGROUND: The most common implant options for the metacarpophalangeal joint arthroplasty include silicone, pyrocarbon and metal-polyethylene. A systematic review of outcomes of silicone and pyrocarbon implants was conducted; however, a similar exercise for metal-polyethylene implants revealed a scarcity of published results and lack of long-term follow-up studies. The aim of the present work is to test the hypothesis that the magnitude of metacarpophalangeal joint cyclic loads generates stress and strain behaviour, which leads to long-term reduced risk of metal-polyethylene component loosening...
January 22, 2019: Clinical Biomechanics
Vitor Guarçoni de Paula, Gerson Bonfante, Fabio C Lorenzoni, Paulo G Coelho, Leonardo Rigoldi Bonjardim, Vinicius P Fardin, Estevam A Bonfante
OBJECTIVE: To evaluate the probability of survival of monolithic and porcelain veneered lithium disilicate crowns comprised by a conventional or modified core when loaded on marginal ridges. METHODS: Lithium disilicate molar crowns (n=30) were fabricated to be tested at mesial and distal marginal ridges and were divided as follows: (1) bilayered crowns with even-thickness 0.5mm framework (Bi-EV); (2) bilayered crowns with modified core design (Bi-M-lingual collar connected to proximal struts), and: (3) monolithic crowns (MON)...
January 24, 2019: Dental Materials: Official Publication of the Academy of Dental Materials
Sathyanarayanan Sridhar, Frederick Wang, Thomas G Wilson, Kelli Palmer, Pilar Valderrama, Danieli C Rodrigues
Currently many assume that bacteria are the primary etiological factor associated with failure of titanium dental implants. However, emerging data indicates a possible role for mechanical forces in implant failure. This study is based on the hypothesis that the synergistic effect of mechanical forces and bacterial biofilm can lead to surface damage resulting in in vivo release of metallic particles. The primary aim of the study was to develop a dynamic fatigue test method for dental implants immersed in wet environments such as; (i) 0...
January 17, 2019: Journal of the Mechanical Behavior of Biomedical Materials
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"