The aim of this study was to investigate the effect of 50% hydrofluoric acid (HF) surface treatment on the cyclic fatigue resistance (CFR) of K3 NiTi instruments. Twenty as-received and twenty HF-treated K3 NiTi instruments were compared in CFR. The surface texture and fracture surface of two instrument groups were examined with a scanning electron microscope (SEM). Additionally, any change of ...

OBJECTIVE The changes in fatigue resistance of nickel-titanium rotary ProFile instruments after clinical use for shaping 10 curved molar root canals were evaluated in this study. STUDY DESIGN Twenty-five sets of files #20, #25, and #30 and tapers .04 and .06 were divided into 2 groups, one with 10 sets of new files that were tested in a fatigue test bench device as a control. The other, exper...

The wide range of applications within Rolls-Royce engines has led to the policy of developing single crystal alloys with specific targets. This has resulted in a comprehensive family of alloys which meets the requirements of particular engine applications. SRR99 is a high strength alloy to replace DS MM002 in applications where increased creep, tensile and fatigue strength are required. RR2000 ...

In shot peening process the work piece surface is struck by a large number of balls and compressive residual stress is generated on the surface. So, mechanical properties such as fatigue strength, stress corrosion resistance, smooth shape and ... will improve. In this paper, the balls with a speed of 100 to 200 m/s were struck on the steel samples and fatigue strength compared with specimens wi...

The cyclic fatigue resistance of K3 and EndoSequence files was compared by rotating files against a highly polished surface inclined at 15 degrees to the horizontal. For each brand, files with a 25 tip in .04 and .06 taper and files with a 40 tip in .04 and .06 taper were tested at both 300 and 600 rpm. A 3-mm axial movement simulated a clinical pecking motion at 1 cycle per second. The number ...

The aim of this study was to comparatively evaluate the bending resistance at 45º, the static and dynamic cyclic fatigue life, and the fracture type of the WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) 25-08 and Reciproc (VDW, Munich, Germany) 25-08 instruments. A total of 60 nickel-titanium (NiTi) instruments (30 Reciproc and 30 WaveOne) from three different lots, each of which was 25 ...

Increasing use of aluminum shape castings in automotive and aerospace industries has drawn great attention to fatigue properties of cast aluminum components. The fatigue resistance of aluminum castings strongly depends upon the presence of casting flaws and characteristics of microstructural constituents. The existence of casting flaws significantly reduces fatigue crack initiation life. In the...

D. Aguirre-Guerrero, A. Juárez-Hernández, M.A.L. Hernández-Rodríguez, University Autonumous of Nuevo León, Faculty of Mechanical and Electrical Engineering, Nuevo León, México. R. Morales, I. Ruiz, PEMSA Co. Celaya, Guanajuato, México. The eff ect of initial plastic strain c ycle fatigue lives of HSLA specimens is in vestigated. Specimens were monotonically, quasi-statically loaded under strain...

Mechanical stress-strain hysteresis, temperature and electrical resistance measurements were performed for the detailed characterisation of the fatigue behaviour of the quenched and tempered steel SAE 4140 (42CrMo4) under constant amplitude loading and service loading. On the basis of generalised Morrow and Basquin equations the fatigue life calculation method “PHYBAL” was developed. Short cons...

AIM To compare cyclic fatigue resistance of two geometrically similar nickel-titanium instruments, used in conditions similar to clinical use in reciprocating and continuous rotary motion. METHODOLOGY Four groups of eighteen instruments each, Reciproc(®) files sizes ISO 25 and 40 (R25 and R40) and Mtwo(®) files sizes ISO 25 and 40 (M25 and M40), were tested in reciprocating and continuous rot...