The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Marc Engelsdeutsch - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical analysis of penetration removal response of Endodontic Instrument made of single crystal cu based sma comparison with niti sma Instruments
Smart Materials and Structures, 2017Co-Authors: Marin Vincent, P Xolin, A M Gevrey, Frederic Thiebaud, Marc EngelsdeutschAbstract:This paper presents an experimental and numerical study showing that single crystal shape memory alloy (SMA) Cu-based Endodontic Instruments can lead to equivalent mechanical performances compared to NiTi-based Instruments besides their interesting biological properties. Following a previous finite element analysis (FEA) of single crystal CuAlBe Endodontic Instruments (Vincent et al 2015 J. Mater. Eng. Perform. 24 4128–39), prototypes with the determined geometrical parameters were machined and experimentally characterized in continuous rotation during a penetration/removal (P/R) protocol in artificial canals. The obtained mechanical responses were compared to responses of NiTi Endodontic files in the same conditions. In addition, FEA was conducted and compared with the experimental results to validate the adopted modeling and to evaluate the local quantities inside the Instrument as the stress state and the distribution of volume fraction of martensite. The obtained results highlight that single crystal CuAlBe SMA prototypes show equivalent mechanical responses to its NiTi homologous prototypes in the same P/R experimental conditions.
Letícia C. Souza - One of the best experts on this subject based on the ideXlab platform.
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Influence of the Geometry of Curved Artificial Canals on the Fracture of Rotary Nickel-Titanium Instruments Subjected to Cyclic Fatigue Tests
Journal of Endodontics, 2013Co-Authors: Hélio Pereira Lopes, Edson Jorge Lima Moreira, Carlos Nelson Elias, José F. Siqueira, Márcia Valéria Boussada Vieira, Lucio Souza Gonçalves, Victor Talarico Leal Vieira, Letícia C. SouzaAbstract:Abstract Introduction This study evaluated the influence of different features of canal curvature geometry on the number of cycles to fracture of a rotary nickel-titanium Endodontic Instrument subjected to a cyclic fatigue test. Methods BioRaCe BR4C Instruments (FKG Dentaire, La Chaux-de Fonds, Switzerland) were tested in 4 grooves simulating curved metallic artificial canals, each one measuring 1.5 mm in width, 20 mm in total length, and 3.5 mm in depth with a U-shaped bottom. The parameters of curvature including the radius and arc lengths and the position of the arc differed in the 4 canal designs. Fractured surfaces and helical shafts of the separated Instruments were analyzed by scanning electron microscopy. Results The Student's t test showed that a significantly lower number of cycles to fracture values were observed for Instruments tested in canals with the smallest radius, the longest arc, and the arc located in the middle portion of the canal. Scanning electron microscopic analysis of the fracture surfaces revealed morphologic characteristics of ductile fracture. Plastic deformation was not observed in the helical shaft of the fractured Instruments. Conclusions Curvature geometry including the radius and arc lengths and the position of the arc along the root canal influence the number of cycles to fracture of rotary nickel-titanium Instruments subjected to flexural load.
Marin Vincent - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical analysis of penetration removal response of Endodontic Instrument made of single crystal cu based sma comparison with niti sma Instruments
Smart Materials and Structures, 2017Co-Authors: Marin Vincent, P Xolin, A M Gevrey, Frederic Thiebaud, Marc EngelsdeutschAbstract:This paper presents an experimental and numerical study showing that single crystal shape memory alloy (SMA) Cu-based Endodontic Instruments can lead to equivalent mechanical performances compared to NiTi-based Instruments besides their interesting biological properties. Following a previous finite element analysis (FEA) of single crystal CuAlBe Endodontic Instruments (Vincent et al 2015 J. Mater. Eng. Perform. 24 4128–39), prototypes with the determined geometrical parameters were machined and experimentally characterized in continuous rotation during a penetration/removal (P/R) protocol in artificial canals. The obtained mechanical responses were compared to responses of NiTi Endodontic files in the same conditions. In addition, FEA was conducted and compared with the experimental results to validate the adopted modeling and to evaluate the local quantities inside the Instrument as the stress state and the distribution of volume fraction of martensite. The obtained results highlight that single crystal CuAlBe SMA prototypes show equivalent mechanical responses to its NiTi homologous prototypes in the same P/R experimental conditions.
Hélio Pereira Lopes - One of the best experts on this subject based on the ideXlab platform.
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Influence of the Geometry of Curved Artificial Canals on the Fracture of Rotary Nickel-Titanium Instruments Subjected to Cyclic Fatigue Tests
Journal of Endodontics, 2013Co-Authors: Hélio Pereira Lopes, Edson Jorge Lima Moreira, Carlos Nelson Elias, José F. Siqueira, Márcia Valéria Boussada Vieira, Lucio Souza Gonçalves, Victor Talarico Leal Vieira, Letícia C. SouzaAbstract:Abstract Introduction This study evaluated the influence of different features of canal curvature geometry on the number of cycles to fracture of a rotary nickel-titanium Endodontic Instrument subjected to a cyclic fatigue test. Methods BioRaCe BR4C Instruments (FKG Dentaire, La Chaux-de Fonds, Switzerland) were tested in 4 grooves simulating curved metallic artificial canals, each one measuring 1.5 mm in width, 20 mm in total length, and 3.5 mm in depth with a U-shaped bottom. The parameters of curvature including the radius and arc lengths and the position of the arc differed in the 4 canal designs. Fractured surfaces and helical shafts of the separated Instruments were analyzed by scanning electron microscopy. Results The Student's t test showed that a significantly lower number of cycles to fracture values were observed for Instruments tested in canals with the smallest radius, the longest arc, and the arc located in the middle portion of the canal. Scanning electron microscopic analysis of the fracture surfaces revealed morphologic characteristics of ductile fracture. Plastic deformation was not observed in the helical shaft of the fractured Instruments. Conclusions Curvature geometry including the radius and arc lengths and the position of the arc along the root canal influence the number of cycles to fracture of rotary nickel-titanium Instruments subjected to flexural load.
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influence of curvature location along an artificial canal on cyclic fatigue of a rotary nickel titanium Endodontic Instrument
Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, 2011Co-Authors: Hélio Pereira Lopes, Edson Jorge Lima Moreira, Carlos Nelson Elias, Wanderson Miguel Maia Chiesa, Norbi Rodrigues Correia, Nubia Carvalho De Souza Navegante, Bianca Esther Cabral ChiesaAbstract:Objectives This study evaluated the effects of curvature location along an artificial canal on cyclic fatigue (CF) of an Mtwo rotary Instrument, verifying the number of cycles to fatigue fracture (NCF) and morphologic characteristics of the fractured Instruments. Study design CF testing of Instruments was performed in artificial canals with curvature radii of 10 mm and arc lengths of 11 mm. Mtwo rotary Instruments size 40, 0.04 taper were used in 2 groups (n = 10): group A, curvature positioned on middle part; group B, apical curvature. All Instruments were rotated until fracture. The number of cycles to failure was registered. Data were analyzed by independent sample t test. Fractured surfaces and the helical shafts of the Instruments were analyzed by scanning electron microscopy. Results NCF for groups A and B had significant statistic differences ( P Conclusions The number of cycles to fracture of the Mtwo Instruments increased when the arc was changed from the middle to the apical part of the canal. The morphologic characteristics of the fractured surfaces were of the ductile type.
Francesco Migliavacca - One of the best experts on this subject based on the ideXlab platform.
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numerical study on the influence of material characteristics on ni ti Endodontic Instrument performance
Journal of Materials Engineering and Performance, 2009Co-Authors: Lorenza Petrini, Silvia Necchi, Silvio Taschieri, Francesco MigliavaccaAbstract:Ni-Ti rotary Endodontic Instruments (files) are used in dentistry during the Endodontic treatment to shape the root canal of the tooth while removing the pulp when infected. Up to now, the studies for evaluating their performances and drawbacks were mainly limited to experimental tests on product flexural and torsional resistance. This work exploits computational analyses for investigating the effects of materials with different mechanical properties on the behavior of rotary Endodontic Instruments. The aim is to understand the appropriate material choice to reduce the criticality of the treatment in particular clinical conditions. In particular, the interaction between an accurately modeled rotating file and differently shaped root canals during the clinical procedure was studied performing finite element analyses. Strains induced by the treatment on a file made of a “standard” Ni-Ti alloy (characterized by average properties of the pseudoelastic behavior), a “long” Ni-Ti alloy (characterized by wide transformation region), a “super” Ni-Ti alloy (characterized by an extended Hookian behavior without transformation region), and stainless steel were compared. The results accurately show the advantages of the use of Ni-Ti alloy with respect to stainless steel and the better performance of the “long” alloy in all the tested case.