21 results match your criteria vickers martens

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Mapping of the Micro-Mechanical Properties of Human Root Dentin by Means of Microindentation.

Materials (Basel) 2021 Jan 21;14(3). Epub 2021 Jan 21.

Clinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

The extensive knowledge of root dentin's mechanical properties is necessary for the prediction of microstructural alterations and the teeth's deformations as well as their fracture behavior. Standardized microindentation tests were applied to apical, medial, and cervical root sections of a mandibular human first molar to determine the spatial distribution of the hard tissue's properties (indentation modulus, indentation hardness, Martens hardness, indentation creep). Using an indentation mapping approach, the inhomogeneity of mechanical properties in longitudinal as well as in transversal directions were measured. Read More

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January 2021

Correlation of the mechanical and biological response in light-cured RBCs to receiving a range of radiant exposures: Effect of violet light.

J Dent 2021 Feb 29;105:103568. Epub 2020 Dec 29.

Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, Canada.

Objective: This study correlates the mechanical and biological response of commercially available resin-based composites (RBCs) to clinically relevant light-curing conditions.

Methods: Two RBCs (Venus and Venus Pearl; Kulzer) that use different monomer and photo-initiator systems, but have a similar filler volume and shade, were exposed to either just blue light, or violet and blue light from two different LCUs (Translux Wave and Translux 2Wave; Kulzer). Distance and exposure times were adjusted so that both LCUs delivered 5 similar levels of radiant exposures (RE) between 1. Read More

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February 2021

Spatial Distribution of the Micro-Mechanical Properties in High-Translucent CAD/CAM Resin-Composite Blocks.

Authors:
Nicoleta Ilie

Materials (Basel) 2020 Jul 28;13(15). Epub 2020 Jul 28.

Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestr. 70, D-80336 Munich, Germany.

Industrially cured, high-translucent computer-aided design/computer-aided manufacturing (CAD/CAM) resin-based composites (RBC) are the most recently launched dental restoratives. Clinical treatments and laboratory tests are based on a homogeneous distribution of properties within CAD/CAM blocks to obtain constant and reproducible results. The study therefore aims to determine the spatial distribution of various micro-mechanical parameters (Vickers hardness, Martens hardness, indentation modulus, creep, elastic and total indentation work) in five representative CAD/CAM RBCs. Read More

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Comparing the mechanical properties of pressed, milled, and 3D-printed resins for occlusal devices.

J Prosthet Dent 2020 Dec 17;124(6):780-786. Epub 2020 Jan 17.

Research Associate, Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Basel, Switzerland. Electronic address:

Statement Of Problem: Comparisons of the material qualities of pressed, milled, and 3D-printed occlusal devices are sparse, complicating informed decisions on material choice.

Purpose: The purpose of this in vitro study was to compare the material properties of pressed, milled, and 3D-printed resins, as well as how these are affected by thermal aging. These data were then used to estimate the likely clinical performance of the tested materials. Read More

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December 2020

A Comparison of the Compositional, Microstructural, and Mechanical Characteristics of Ni-Free and Conventional Stainless Steel Orthodontic Wires.

Materials (Basel) 2019 Oct 19;12(20). Epub 2019 Oct 19.

Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, Faculty of Medicine, University of Zurich, 8032 Zurich, Switzerland.

Ni-free orthodontic wires were introduced to mitigate concerns associated with the use of Ni-containing alloys in orthodontics. However, limited information is available on their properties and therefore, the aim of this study was to characterize the elemental composition, the microstructure, and the mechanical properties of Ni-free orthodontic wires and compare them with their stainless steel (SS) counterparts. Four Ni-free and four conventional SS wires were included in this study. Read More

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October 2019

Surface, Microstructural, and Mechanical Characterization of Prefabricated Pediatric Zirconia Crowns.

Materials (Basel) 2019 Oct 9;12(20). Epub 2019 Oct 9.

Clinic of Orthodontics and Pediatric Dentistry, Centrer of Dental Medicine, University of Zurich, 8032 Zurich, Switzerland.

The purpose of this study was to characterize the surface roughness, the microstructure, and mechanical properties of four prefabricated zirconia pediatric crowns. Ten prefabricated crowns from four different manufacturers (Cheng Crowns Zirconia), (EZCrowns), (NuSmile ZR), and (Zirconia Pediatric Crowns) were included in this study. The surface roughness parameters (Sa, Sq, Sz, Sc, and Sv) of all samples were studied by optical profilometry and then the microstructure was studied by Raman spectroscopy. Read More

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October 2019

Water-induced Effects on the Hardness and Modulus of Contemporary Sealants Derived from Instrumented Indentation Testing (IIT).

J Contemp Dent Pract 2019 Jun 1;20(6):653-656. Epub 2019 Jun 1.

Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zuirch, Switzerland, Phone: +41 446343210, e-mail:

Aim: To compare the mechanical properties of four different types of contemporary fissure sealants before and after water storage employing a modern instrumented indentation testing (IIT) method.

Materials And Methods: Four different types of materials used in everyday practice were deliberately selected. Fissurit (FIS) is a highly filled resin, Embrace (EMB) is a bisphenol A (BPA)-free unfilled resin, Helioseal (HEL) is an unfilled resin, and Riva Protect (RIV) is a glass-ionomer material. Read More

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Creep, Hardness, and Elastic Modulus of Lingual Fixed Retainers Adhesives.

Materials (Basel) 2019 Feb 21;12(4). Epub 2019 Feb 21.

Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.

The aims of this study were twofold: a) to characterize a wide array of time-independent and -dependent properties and b) to find possible correlations among the properties tested. Seven commercially available orthodontic adhesives were included in this study and ten cylindrical specimens were prepared from each material. Five specimens from each material were used for the characterization of Martens Hardness (HM), indentation modulus (E), and elastic index (η), and the remaining five for the determination of indentation creep (C). Read More

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February 2019

Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia.

N Engl J Med 2019 01 10;380(1):11-22. Epub 2018 Nov 10.

From Brigham and Women's Hospital Heart and Vascular Center and Harvard Medical School, Boston (D.L.B.); FACT (French Alliance for Cardiovascular Trials), Département Hospitalo-Universitaire FIRE (Fibrose, Inflammation, and Remodeling), Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, Université Paris-Diderot, INSERM Unité 1148, Paris (P.G.S.); National Heart and Lung Institute, Imperial College, Royal Brompton Hospital, London (P.G.S.); the Department of Medicine, University of Maryland School of Medicine, Baltimore (M.M.); the Utah Lipid Center, Salt Lake City (E.A.B.); the Office of Health Promotion and Disease Prevention, Department of Medicine, Emory University School of Medicine, Atlanta (T.A.J.); Amarin Pharma, Bedminster, NJ (S.B.K., R.T.D.J., R.A.J., L.J., C.G.); Montreal Heart Institute, Université de Montréal, Montreal (J.-C.T.); and the Department of Medicine, Baylor College of Medicine, and the Center for Cardiovascular Disease Prevention, Methodist DeBakey Heart and Vascular Center, Houston (C.M.B.).

Background: Patients with elevated triglyceride levels are at increased risk for ischemic events. Icosapent ethyl, a highly purified eicosapentaenoic acid ethyl ester, lowers triglyceride levels, but data are needed to determine its effects on ischemic events.

Methods: We performed a multicenter, randomized, double-blind, placebo-controlled trial involving patients with established cardiovascular disease or with diabetes and other risk factors, who had been receiving statin therapy and who had a fasting triglyceride level of 135 to 499 mg per deciliter (1. Read More

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January 2019

Setting characteristics and mechanical properties of self-adhesive resin luting agents.

Dent Mater 2017 03 4;33(3):344-357. Epub 2017 Feb 4.

Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Greece. Electronic address:

Objective: To evaluate the degree of conversion (DC%), salt yield and mechanical properties of self-adhesive luting agents (SAA) set under dual-cure (E) and self-cure (NE) modes.

Methods: Three SAA (GC LinkAce/GCLA, MaxCem Elite/MXEL, Rely-X Unicem 2/RXUN) and an adhesive resin luting agent (Rely-X Ultimate/RXUL-control) were used. The properties tested under E and NE modes were a) DC% and phosphate salt yield after 10min, 1h (h) and 3 weeks (w) storage, by infrared spectroscopy; and b) the mechanical properties of 3w-stored specimens by instrumented indentation testing (Martens hardness/HM, Elastic modulus/EIT, Elastic index/ηIT) and microscopic Vickers hardness/VH. Read More

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The effect of simulating porcelain firing on the elemental composition, microstructure, and mechanical properties of electroformed gold restorations.

J Dent Sci 2016 Sep 15;11(3):266-271. Epub 2016 Apr 15.

Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.

Background/purpose: The mechanical properties of pure gold (Au) are modified by thermal treatments. Thus, the aim of this study was to evaluate the effect of porcelain firing on the elemental composition, microstructure, and mechanical properties of electroformed Au crowns.

Materials And Methods: Twenty electroformed Au specimens were prepared and divided into two groups. Read More

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September 2016

Mechanical properties of contemporary orthodontic adhesives used for lingual fixed retention.

Biomed Tech (Berl) 2017 May;62(3):289-294

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Objective: The aim of the present study was to test the mechanical properties of different adhesives used in orthodontics for fixed retainers and to investigate their possible interrelations.

Materials And Methods: Specimens of six different adhesive resins were prepared: Transbond XT, Transbond LR and an experimental BPA-free orthodontic adhesive, as well as IPS Empress Direct (IPS-ED), ZNano and Accolade. The mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), the ratio of elastic to total work, commonly known as elastic index (ηIT) and Vickers hardness (HV). Read More

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Elemental, microstructural, and mechanical characterization of high gold orthodontic brackets after intraoral aging.

Biomed Tech (Berl) 2017 Feb;62(1):97-102

The purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Read More

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February 2017

Chemical and mechanical characteristics of contemporary thermoplastic orthodontic materials.

Aust Orthod J 2015 Nov;31(2):165-70

Aim: The aim of the present study was to characterise the chemical and mechanical properties of contemporary thermoplastic orthodontic materials.

Materials And Methods: Four thermoplastic materials were tested: Clear Aligner (Scheu-Dental), ACE and A+ (Dentsply), and Invisalign (Align Technology). Eight appliances were fabricated from each material and a small portion from each was analysed by ATR-FTIR spectroscopy. Read More

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November 2015

Development and testing of novel bisphenol A-free adhesives for lingual fixed retainer bonding.

Eur J Orthod 2017 Feb 11;39(1):1-8. Epub 2015 Dec 11.

****Department of Biomaterials, School of Dentistry, University of Athens, Greece.

Aim: To comparatively evaluate the properties of two BPA-free experimental adhesives (EXA, EXB) for lingual fixed retainer bonding versus a commercially available reference material (Transbond LR-TLR) based on BPA-compound.

Materials And Methods: The experimental materials were a flowable 60 per cent glass filler-filled UEDMA/TEGDMA flowable composite (EXB) and a 70 per cent glass filler-filled paste composite with PCDMA/UEDMA/TEGDMA co-monomers. The properties tested were degree of conversion (DC%), mechanical properties (Martens hardness-MH, elastic modulus-E, elastic index-n), effect of prolonged (6 months) water storage (changes in Vickers microhardness-VHN) and pull-out strength employing a multi-stranded wire. Read More

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February 2017

Mechanical properties of orthodontic wires derived by instrumented indentation testing (IIT) according to ISO 14577.

Prog Orthod 2015 19;16:19. Epub 2015 Jun 19.

Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Thivon 2 str., Goudi 11527, Athens, Greece,

Background: The aim of this study was the characterization of mechanical properties of representative types of orthodontic wires employing instrumented indentation testing (IIT) according to ISO 14577.

Methods: Segments were cut from ten wires. The first six are made of stainless steel (SS), two are made of Ni-Ti, and the last two are made of titanium molybdenum alloys (TMA). Read More

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Setting characteristics of a resin infiltration system for incipient caries treatment.

J Dent 2015 Jun 8;43(6):715-9. Epub 2015 Apr 8.

Department of Orthodontics and Paediatric Dentistry, Centre of Dental Medicine, University of Zurich, Switzerland. Electronic address:

Objectives: This study investigated the curing efficiency, the extent of atmospheric oxygen inhibition to the polymerization reaction and the mechanical properties of a new resin-infiltration system for caries treatment.

Methods: The curing efficiency was estimated by measuring the percentage degree of cure (%DC) of thin resin films (h: 150μm, Ø: 5mm, n=3), 10min after 40s exposure to a quartz halogen bulb (750mW/cm2) light curing unit (Optilux 501, Demetron/Kerr, USA), in the absence of O2, by micro ATR-FTIR spectroscopy. The extent of O2 inhibition on resin film setting (width in μm) was assessed by transmission optical microscopy on thin films (h: 150μm, Ø: ∼7mm, n=5) placed between two transparent cover slips and exposed to air from lateral sites. Read More

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An in vitro comparison of fluorescence-aided caries excavation and conventional excavation by microhardness testing.

Clin Oral Investig 2014 24;18(2):599-605. Epub 2013 May 24.

Department of Endodontics and Operative Dentistry, Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China,

Objective: The aim of this in vitro study was to compare fluorescence-aided caries excavation with conventional excavation based on the Martens and Vickers hardness of dentin at the cavity floor after caries removal.

Materials And Methods: In total, 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves, which were assigned to either the fluorescence-aided caries excavation group or the conventional excavation group. After the treatment, embedding, mounting, and polishing, a line of indentations from the dental pulp across the sound dentin to the cavity floor was made on each sample. Read More

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December 2015

Surface carbonization of titanium for abrasion-resistant implant materials.

Dent Mater J 2007 Mar;26(2):245-53

Biomedical, Dental Materials and Engineering, Department of Oral Health Science, Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586, Japan.

Carbide layer was formed on the surface of Ti by heating in hydrocarbon atmosphere (benzene C6H6) at 1000-1400 degrees C using a high frequency induction heating method. Physical and mechanical properties of carbide-coated Ti were investigated to examine its potential as an abrasion-resistant implant material. Scanning electron microscopy (SEM) showed that the surface of Ti was covered with fine grains of 1-4 microm diameter, depending on heating conditions. Read More

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Hardness measured with traditional Vickers and Martens hardness methods.

Dent Mater 2007 Sep 4;23(9):1079-85. Epub 2006 Dec 4.

Department of Restorative Dentistry, School of Dental Sciences, University of Newcastle upon Tyne, UK.

Objective: To determine the differences, if any, between hardness measured with traditional Vickers and Martens hardness test methods on denture teeth under 2, 10 and 50 N loads.

Method: Hardness of acrylic resin (VIV), composite resin (ORT) and porcelain (POR) denture tooth materials was measured using a traditional Vickers hardness (HV) method and Martens hardness (HM) method at 2, 10 and 50N test loads. Vickers hardness was also calculated from the force-indentation depth curves (HVfid) that were recorded during Martens hardness. Read More

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September 2007

[Studies on bond strength and hardness of base materials].

Shigaku 1989 Apr;76(7):1394-411

Since base materials are used in the construction of abutment teeth and the cavity walls of the teeth with healthy pulp, they need considerable bonding and mechanical strength depending on the site of application. In the present study we examined bonding strength, Martens-Mayer hardness and Vickers hardness of base materials in comparison with natural dentin in order to reevaluate them in terms of prosthetic materials and to provide assessment criteria for their application to prosthetic treatment. The results were as follows: 1) The bonding test showed the lowest value (4. Read More

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