Nickel-titanium rotary instruments are important adjuncts in endodontic therapy. This review attempts to identify factors that influence shaping outcomes with these files, such as preoperative root-canal anatomy and instrument tip design. Other, less significant factors include operator experience, rotational speed, and specific instrument sequence. Implications of various working length defini...

Since the end of the nineteenth century, automated root canal instrumentation has been available, but systems had many problems. The challenges of increased canal blockage, instrument breakage, and insufficient canal debridement were related to the use of stainless steel instruments and have been dramatically improved with the introduction of nickel-titanium (NiTi) files. The first useable NiTi...

OBJECTIVE To evaluate the effect of number of uses, angle and radius of curvature and type of instrument on the fracture of ProTaper rotary instruments when used by undergraduate students. STUDY DESIGN Three hundred and seventy-six molars, with a total of 1114 root canals, extracted were instrumented by undergraduate students using ProTaper instruments according to the manufacturer´s recommen...

ROTARY HAPTIC KNOB FOR VEHICULAR INSTRUMENT CONTROLS Mircea Badescu, Charles Wampler * and Constantinos Mavroidis 1 Department of Mechanical and Aerospace Engineering Rutgers University, The State University of New Jersey 98 Brett Rd., Piscataway, NJ, USA 08854-8058 TEL: 732 445 0732, FAX: 732 445 -3124, EMAIL: @jove.rutgers.edu 2 Manufacturing and Design Systems Department Gen...

Background. This study was designed to compare the viability of autogenous bone grafts, harvested using different methods, in order to determine the best harvesting technique with respect to more viable cells. Methods. In this animal experimental study, three harvesting methods, including manual instrument (chisel), rotary device and piezosurgery, were used for harvesting bone grafts from the l...

Successful endodontic treatment mainly relies on preserving the original anatomy of the root canal while avoiding instrument fractures and iatrogenic preparation errors, such as loss of working length, zipping, or ledging [1,2]. In most cases, rotary instrumentation has proved a valuable advancement for meeting these parameters. Unlike stainless steel files, nickel-titanium instruments have suf...

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...

NiTi instrument separation is a serious concern in endodontic therapy. The analysis of NiTi files after torsional fracture reveals that the majority of torsional separations occur in the last mm. of the files and in the files with lower taper and/ or diameter. Consequentely, the tip of the smaller files presents the higher risk of torsional fracture and should be protected using low torque moto...

NiTi instrument separation is a serious concern in endodontic therapy. The analysis of NiTi files after torsional fracture reveals that the majority of torsional separations occur in the last mm. of the files and in the files with lower taper and/ or diameter. Consequentely, the tip of the smaller files presents the higher risk of torsional fracture and should be protected using low torque moto...

The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress nee...