AIM To evaluate the cyclic fatigue fracture resistance of engine-driven F2 ProTaper instruments under reciprocating movement. METHODOLOGY A sample of 30 NiTi ProTaper F2 instruments was used. An artificial canal was made from a stainless steel tube, allowing the instruments to rotate freely. During mechanical testing, different movement kinematics and speeds were used, which resulted in three...

Five types of porous Nickel-Titanium (NiTi) alloy samples of different porosities and pore sizes were fabricated. According to compressive and fracture strengths, three groups of porous NiTi alloy samples underwent further cytocompatibility experiments. Porous NiTi alloys exhibited a lower Young's modulus (2.0 GPa ~ 0.8 GPa). Both compressive strength (108.8 MPa ~ 56.2 MPa) and fracture strengt...

Coated archwires and ceramic brackets have been developed to improve facial esthetics during orthodontic treatment. However, their mechanical behavior has been shown to be different from metallic archwires and brackets. Therefore, the aim of this study was to compare the deflection forces in coated nickel-titanium (NiTi) and esthetic archwires combined with ceramic brackets. Material and Method...

NiTi powders are densified in the presence of argon gas, whose initial pressure is varied between 1 and 33 atm, to create NiTi billets containing isolated Ar-filled pores. Upon vacuum annealing, the pressurized pores expand by creep of the surrounding NiTi matrix at rates which are in agreement with a simple analytical model up to 16% porosity. Beyond this porosity, foaming becomes very slow, a...

INTRODUCTION Root canal preparation is an important process in endodontic therapy. Nickel-titanium (NiTi) rotary file system can be used in single length technique (simultaneous technique) without early coronal enlargement, as well as in crown-down method. The purpose of this in vitro study was to compare single length with crown-down methods' shaping ability using Mtwo NiTi files. MATERIALS ...

UNLABELLED   INTRODUCTION Rotary nickel-titanium (NiTi) instruments are thought to allow shaping of narrow, curved root canals more efficiently and more effectively than stainless steel hand instruments. However, the continued search for even more effective and safer instruments has resulted in new rotary systems being introduced on a regular basis. The aim of this study was to compare shapin...

Coronal preflaring NiTi files should possess proper hardness, resistance to fracture and flexibility. This study compared the bending cyclic fatigue of three orifice files. HyFlex EDM Orifice opener (#25/12), CM (#25/08) One Flare (#25/09) were tested (n = 46/instrument). Bending was assessed with stress when perpendicular displacement applied a 3 mm point from file tip, performed at either roo...

OBJECTIVES To compare the influence of type and dimensions of the apical preparation on the cleanliness of the apical area in molars. MATERIAL AND METHODS A total of 120 root canals (MB and DB root canals from 30 maxillary molars and mesial root canals from 30 mandibular molars) were instrumented with Mtwo NiTi rotary instruments to a size 25/0.06 taper and were equally divided into three dif...

Achieving apical foramen patency through surgical maneuvers during the biomechanical preparation of root canals is a goal sought by several schools. The aim of this study was to evaluate the deformation of the foramen as a result of using stainless steel hand files and nickeltitanium rotary instruments for achieving patency. Forty recently extracted dental roots with single canals were calibrat...

A new powder metallurgy technique for creating porous NiTi is demonstrated, combining liquid phase sintering of prealloyed NiTi powders by Nb additions and pore creation by NaCl space-holders. The resulting foams exhibit well-densified NiTi–Nb walls surrounding interconnected pores created by the space-holder, with controlled fraction, size, and shape. Only small amounts of Nb (3 at.%) are need...