OBJECTIVE To compare the deflection load characteristics of homogeneous and heterogeneous joints made by laser welding using various types of orthodontic wires. MATERIALS AND METHODS Four kinds of straight orthodontic rectangular wires (0.017 inch × 0.025 inch) were used: stainless-steel (SS), cobalt-chromium-nickel (Co-Cr-Ni), beta-titanium alloy (β-Ti), and nickel-titanium (Ni-Ti). Homogene...

OBJECTIVE Fluorides can cause corrosion and degradation in mechanical properties of commonly used archwires by forming hydrofluoric acid HF and causing disruption of protective titanium oxide layer. Hence, the aim of this study was to assess the change in load deflection characteristics of Ni-Ti, Cu Ni-Ti, S.S, and β-Ti wires on immersing in fluoride mouth rinses of two types- Phosflur and neut...

To evaluate a Ni-43.5wt%Ti alloy as a new alloy for cast clasp, the fatigue properties of its castings were examined and compared with those of Co-Cr and Type IV Au alloys castings. The Ni-Ti alloy was cast into a phosphate-bonded investment mold using an argon-arc melting and pressure casting machine. The Ni-Ti alloy castings showed superelasticity in bending tests. Fatigue tests were carried ...

Mechanical alloying of Ti-Si and NiTi was performed by high-energy ball milling at ambient temperature. The structural and compositional evolutions during mechanical alloying were investigated. Results showed that the crystallite size of mechanically alloyed Ti-Si and Ni-Ti powders decreased with increasing milling time and the steady-state crystallite size was approximately 10 nm. The mechanic...

A new ohmic contact scheme for gallium nitride is presented. The use of Nitrideforming metal Over Gallide-forming metal, “NOG”, can modify the thermodynamic activity of N and Ga near the interface. This in turn can modify the near-surface point defect concentrations, particularly the vacancies of Ga and N. The principle of this contact scheme was shown to be consistent with results from Ni/Au, ...

AIM The purpose of this study was to evaluate the load and unload deflection and permanent deformation of round 0.016'' and rectangular 0.016'' × 0.022'' regular and coated Ni-Ti wires. MATERIALS AND METHODS Ni-Ti archwires produced by two manufacturers were evaluated. Both regular and coated round and rectangular Ni-Ti wire segments (n = 15) from each group were submitted to a three-point be...

Surface modification with oxide nanostructures is one of the efficient ways to improve physical or biomedical properties of shape memory alloys. This work reports a fabrication of highly ordered Ti-Ni-O nanotube arrays on Ti-Ni alloy substrates through pulse anodization in glycerol-based electrolytes. The effects of anodization parameters and the annealing process on the microstructures and sur...

While the main features of the Fe–Ni–Ti system are well known at low Ti content, literature review of the Ti-rich corner revealed inconsistencies between experimental reports. This investigation presents new experimental results, defined to remove the uncertainties concerning melting behavior and solid-state phase equilibria of the (Ni,Fe)Ti2 phase with the adjacent (Fe,Ni)Ti (B2, CsCl-type str...

The aim of this paper is to present a new method based on numeric calculus to provide data on any type of root canal curvature at any point of the long axis of the canal. Twenty severely curved, simulated root canals were prepared with rotary FlexMaster and Profile instruments in the crown-down technique and manually in the step-back technique. The inner and outer curvatures were registered in ...

The aim of the study was to compare the manual and rotary endodontic instruments focusing on risk of perforation when the whole root canal length is instrumented as well as the time required for preparation in primary teeth Fifty four teeth were divided randomly into three groups.Group I: The root canals were prepared manually with K-files. Group II : ProTaper instruments were used in a crown-d...