Bond strength and interfacial analysis of six CoCr alloys made by conventional casting and selective laser melting.

Purpose: To investigate the effects of the elemental composition and the manufacturing process of cobalt chromium-molybdenum (CoCr-Mo), cobalt chromium-tungsten (CoCr-W), and CoCr-Mo-W alloys on metal-ceramic bond strength.

Materials And Methods: Six CoCr-based alloys were included in this study, a were classified into three different groups depending on their elemental composition (Ν = 10, for each group). The first group had molybdenum (Mo) as the third alloying element, the second group contained tungsten (W) (without Mo), and the third group included both alloying elements.

A SEM/EDS evaluation of debris removal of used rotary Ni-Ti endodontic files by four different cleaning solutions.

Purpose: The aim of this study was to compare the efficacies levels of four cleaning solutions for removing debris from rotary Nickel-Titanium (Ni-Ti) endodontic instruments.

Materials And Methods: Twelve instruments that fractured during ex vivo instrumentation were used. Fractured surfaces were investigated by SEM before and after 3, 6 and 9 min of ultrasonic cleaning in 17 % EDTA.

Microstructural and mechanical characterization of six Co-Cr alloys made by conventional casting and selective laser melting.

Statement Of Problem: Three Co-Cr alloy types (Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W) have been commonly used in the fabrication of dental prostheses. These alloys can be manufactured using either conventional casting or selective laser melting (SLM) techniques. Nevertheless, research that directly compares these materials and/or manufacturing processes in terms of their microstructural and mechanical characteristics is sparse.

Is fatigue mechanism implicated in intraoral fracture of narrow dental implants? A thorough retrieval analysis of two failed implant fixtures retrieved from a single patient.

Purpose: This study aimed to perform a thorough failure analysis of two fractured narrow dental implants after medium-term in vivo use.

Materials And Methods: The top parts of two fractured Narrow Dental Implant (NDI) fixtures were retrieved from two different locations at two different times from the same patient. The NDI-specimen-1 was 12-months in service while the NDI-specimen-2 was 17-months in service.

Does surface priming increase the bond strength of orthodontic brackets? An experimental study.

Objective: To evaluate the effects of metal primer II (MP II) on the shear bond strength (SBS) of orthodontic brackets bonded to teeth and bis-acryl composite provisional material (Bis-Acryl).

Material And Methods: Twenty extracted human premolars specimens and 20 premolar shaped Bis-Acryl specimens were obtained and randomly divided into two surface groups. The first group consisted of human premolars (T) bonded to brackets in the conventional way while in the second (T-MP) MP II was applied on the bracket base before bonding.

Electrochemical characterization of three types of Co-Cr based alloys manufactured by casting and selective laser melting according to ISO 10271.

Objective: To characterize the effect of elemental composition and manufacturing process on the electrochemical properties of Co-Cr-Mo, Co-Cr-W and Co-Cr-Mo-W alloys.

Methods: Six Co-Cr based alloys were included in this study. All alloys are Co-Cr based alloys, classified in three different types according to their elemental composition.

Corrosion resistance of coupled sandblasted, large-grit, acid-etched (SLA) and anodized Ti implant surfaces in synthetic saliva.

Purpose: The purpose of this study was to investigate the corrosion resistance of galvanically coupled SLA and anodized implant surfaces with a Co-Cr alloy.

Materials And Methods: Three groups were included in this study. The first (SLA) was composed of SLA implants (Institut Straumann, Basel, Switzerland), the second (ANO) of NobelReplace® (Nobel Biocare, Göteborg, Sweden), and the third (MIX) of both implant systems combined.

Electrochemical characterization of novel Ag-based brazing alloys for dental applications.

Objective: Taking into account that clinical data have proven the decomposition of Ag brazing alloys used in the production of orthodontic appliances the aim of this study was to develop new Ag based soldering alloys free of Cu and Zn.

Methods: Four commercially available Ag brazing alloys were selected and their electrochemical properties were compared to the following experimental alloys: Ag12Ga, Ag10Ga5Sn, Ag20In and Ag7Sn. 112 disk shape specimens were prepared for each alloy and their electrochemical properties were evaluated by Open Circuit Potential (OCP), linear sweep voltametry (LSV), cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) in a NaCl 0.

Microstructural, mechanical, ionic release and tarnish resistance characterization of porcelain fused to metal Co-Cr alloys manufactured via casting and three different CAD/CAM techniques.

Purpose: To perform a comparative analysis of the microstructure, porosity, mechanical properties, corrosion, and tarnish resistance of Co-Cr alloys prepared by casting and three different computer aided designed/computer aided manufacturing (CAD/CAM) techniques.

Methods: Four groups of metallic specimens were prepared, one each by conventional casting (CST), milling (MIL), selective laser melting (SLM), and milling soft metal (MSM). Ten samples were tested by X-rays, after which their microstructure and elemental composition were tested by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) analysis.

How Hedstrom files fail during clinical use? A retrieval study based on SEM, optical microscopy and micro-XCT analysis.

This study was conducted to evaluate the failure mechanism of clinically failed Hedstrom (H)-files. Discarded H-files (n=160) from #8 to #40 ISO sizes were collected from different dental clinics. Retrieved files were classified according to their macroscopic appearance and they were investigated under scanning electron microscopy (SEM) and X-ray micro-computed tomography (mXCT).

Galvanic coupling of steel and gold alloy lingual brackets with orthodontic wires: Is corrosion a concern?

Objectives: The aim of this research was to assess galvanic behavior of lingual orthodontic brackets coupled with representative types of orthodontic wires.

Materials And Methods: Three types of lingual brackets: Incognito (INC), In-Ovation L (IOV), and STb (STB) were combined with a stainless steel (SS) and a nickel-titanium (NiTi) orthodontic archwire. All materials were initially investigated by scanning electron microscopy / x-ray energy dispersive spectroscopy (SEM/EDX) while wires were also tested by x-ray diffraction spectroscopy (XRD).

Multitechnique characterization of conventional and experimental Ag-based brazing alloys for orthodontic applications.

Objectives: To characterize the microstructure, mechanical properties, ionic release and tarnish resistance of conventional and experimental Ag-based soldering alloys for orthodontic applications.

Methods: Disk shaped specimens were prepared from four commercial Ag based soldering alloys [Dentaurum Universal Silver Solder (DEN), Orthodontic Solders (LEO), Ortho Dental Universal Solder (NOB), and Silver Solder (ORT)] and four experimental alloys Ag12Ga, Ag10Ga5Sn, Ag20In and Ag7Sn. The elemental composition and microstructure was determined by SEM/EDX and XRD analysis, while the mechanical properties were determined by Instrumented Indentation Testing.

Failure analysis of eleven Gates Glidden drills that fractured intraorally during post space preparation. A retrieval analysis study.

The purpose of this study was to determine the failure mechanism of clinically failed Gates Glidden (GG) drills. Eleven retrieved GG drills (sizes #1 to #3) which fractured during root canal preparation were collected and the fracture location was recorded based on macroscopic observation. All fracture surfaces were investigated by a SEM.

Does long-term intraoral service affect the mechanical properties and elemental composition of multistranded wires of lingual fixed retainers?

Purpose: The aim of this study was to evaluate the elemental and mechanical alterations of stainless steel (SS) multistranded orthodontic wires used in fixed retention after intraoral ageing.

Materials And Methods: Two types of 0.022-inch, seven-stranded wires, Lingual Retainer Wire (LRW) and Tru-Chrome (TCH), from the same manufacturer (Rocky Mountain Orthodontics, Denver, Colo, USA) were tested.

Fractographic Analysis of a Clinically Failed FPD After 10 Years in Service.

This study retrieved and analyzed by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) the failure of a single four-unit fixed partial denture (FPD). Low SEM magnifications revealed a smooth/featureless fracture surface, indicating brittle fracture. Higher magnifications revealed a small fatigue fracture region located on the inferior part of the connector.

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

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.

The Effect of Artificial Aging on The Bond Strength of Heat-activated Acrylic Resin to Surface-treated Nickel-chromium-beryllium Alloy.

Purpose: The debonding load of heat-activated polymethylmethacrylate (PMMA) denture base resin material to a nickel-chromium-beryllium (Ni-Cr-Be) alloy conditioned by three different surface treatments and utilizing two different commercial bonding systems was investigated.

Materials And Methods: Denture resin (Lucitone-199) was bonded to Ni-Cr-Be alloy specimens treated with Metal Primer II, the Rocatec system with opaquer and the Rocatec system without opaquer. Denture base resin specimens bonded to non-treated sandblasted Ni-Cr-Be alloy were used as controls.

Chemical and mechanical characteristics of contemporary thermoplastic orthodontic materials.

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.

Surface and cross-sectional characterization of titanium-nitride coated nickel-titanium endodontic files.

Background/purpose: Although the effect of experimental surface modifications on various properties (e.g., fatigue, wear) on coated files have been tested in the past, there is no report for the coating quality of commercially available TiN coated files.

Failure analysis of ParaPost drills that fractured in service: a retrieval analysis study.

The aim was to determine the fracture mechanism of two clinically failed ParaPost drills. First, the fracture planes were analyzed by scanning electron microscopy (SEM). The drill end of one of the fractured pieces of each drill was then embedded in resin and after being metallographically ground and polished, was chemically etched.

Selective Laser Melting Technique of Co-Cr Dental Alloys: A Review of Structure and Properties and Comparative Analysis with Other Available Techniques.

Purpose: The aim of this study was to review the effect of selective laser melting (SLM) procedure on the properties of dental structures made of Co-Cr alloys and to evaluate its quality and compare it to those produced by conventional casting and milling fabrication techniques.

Materials And Methods: A computerized database search using PubMed and Scopus was conducted for peer-reviewed scientific research studies regarding the use of SLM in Co-Cr dental alloys with no restrictions for publication years. The search engines provided hundreds of results, and only 48 scientific research papers, case studies, or literature reviews were considered relevant for this review.

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

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).

Metallurgical characterization of experimental Ag-based soldering alloys.

Aim: To characterize microstructure, hardness and thermal properties of experimental Ag-based soldering alloys for dental applications.

Materials And Methods: Ag12Ga (AgGa) and Ag10Ga5Sn (AgGaSn) were fabricated by induction melting. Six samples were prepared for each alloy and microstructure, hardness and their melting range were determined by, scanning electron microscopy, energy dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD), Vickers hardness testing and differential scanning calorimetry (DSC).

Physico-mechanical properties and prosthodontic applications of Co-Cr dental alloys: a review of the literature.

Cobalt-Chromium (Co-Cr) alloys are classified as predominantly base-metal alloys and are widely known for their biomedical applications in the orthopedic and dental fields. In dentistry, Co-Cr alloys are commonly used for the fabrication of metallic frameworks of removable partial dentures and recently have been used as metallic substructures for the fabrication of porcelain-fused-to-metal restorations and implant frameworks. The increased worldwide interest in utilizing Co-Cr alloys for dental applications is related to their low cost and adequate physico-mechanical properties.

Effects of surface treatment and artificial aging on the shear bond strength of orthodontic brackets bonded to four different provisional restorations.

Objective: To evaluate the combined effects of material type, surface treatment, and thermocycling on the bond strength of orthodontic brackets to materials used for the fabrication of provisional crowns.

Materials And Methods: Four materials were included in this study (ProTemp, Trim Plus, Trim II, and Superpont C+B). Sixty cylindrical specimens (1 × 3 cm) were prepared from each material and equally divided into three groups.