NiTi rotary system in endodontics – An overview

Revista de Chimie

Preservation of the root canal anatomy is very important for the success of endodontic treatment.Properly instrumentation of curvet root canals is influenced by flexibility of endodontic instruments which depends on composition and thermomechanical treatment of the metallic alloy. The aim of the current study was to compare the changes in root canal geometry after the preparation with two systems that work in reciprocating motion (Reciproc25, Primary Wave One) and another one in continuous rotation (One Shape), using CT measurements. Forty-five canals of extracted molars with curvatures ranging from 9 to 40 degrees were chosen for this study. The canals were divided, according to the canal curvature into three homogeneous groups and were prepared with three different rotary systems: group I with Reciproc file 25.08 (VDW, Munich, Germany), group II with Wave One Primary 25.08 (Dentsply-Maillefer Ballaigues, Switzerland) and group III with One Shape 25.06 (Micro Mega, Bensancon, Franc...

American journal of dentistry

The growing use of NiTi rotary instruments in dental practice demands a good understanding of their concept of alloy and design in relation to improved properties and inherent limitations. Nickel titanium's super elasticity allows more centered canal preparations with less transportation and a decreased incidence of canal aberrations. Furthermore, the production of files with increased taper became possible. This is of special importance because of concerns on the achievement of adequate irrigation and close adaptation of the filling material during endodontic treatment. Unique shaft and tip designs should permit the use of a rotary handpiece allowing different tactile awareness. On the other hand, special attention is paid to maximize cutting efficiency and cutting control throughout instrumentation. NiTi rotary instruments are generally used in a crown-down approach and a continuous reaming motion. Consequently, rounder root canal preparations, with less straightening and a smaller amount of apical extrusion is achievable. In spite of their increased flexibility, separation is still a concern with NiTi files. The phenomenon of repeated cyclic metal fatigue and the variable of torsional loading are two important factors in instrument fracture. However, with awareness of the appropriate manipulation and special attention to the equipment used, NiTi systems are safe with a minimal incidence of instrument failure. (Am J Dent 2001;14:324-333).

Materials

Objectives: This study aimed to compare the ex vivo performance of two rotary nickel–titanium (NiTi) systems with similar designs but manufactured from martensitic and austenitic alloys, the One Curve (OC) and One Shape (OS) rotary endodontic files, respectively. Methods: Forty separate mesial canals of 20 extracted mandibular molars were scanned using micro-computed tomography (CT), which were divided into 2 groups and instrumented with OC and OS, respectively. Post-instrumentation micro-CT scans were evaluated using validated computer algorithms to compare changes in canal thickness, surface area, structure model index (SMI) scores, volume of removed dentin, percentage of untreated canal surface, percentage of curvature straightening, and the amount of canal transportation. Results: Both files led to significant changes in the basic root canal geometry, with no preparation errors and no statistically significant differences. However, OC treatment resulted in significantly less cur...

Journal of Endodontics, 2012

Introduction: A great number of nickel-titanium (NiTi) rotary systems with noncutting tips, different crosssections, superior resistance to torsional fracture, varying tapers, and manufacturing method have been introduced to the market. The purpose of this study was to evaluate and compare the effect of 4 rotary on volumetric changes and transportation of curved root canals. Methods: Forty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 25 to 40 were divided according to the instrument used in canal preparation into 4 groups of 10 samples each: group RS, group TF, group GTX, and group PT. Canals were scanned using an i-CAT CBCT scanner (Imaging Science International, Hatfield, PA) before and after preparation to evaluate the volumetric changes. Root canal transportation and centering ratio were evaluated at 1.3, 2.6, 5.2, and 7.8 mm from the apex. The significance level was set at P # .05. Results:

IP Indian Journal of Conservative and Endodontics, 2021

The most important step in the success of the root canal treatment is the proper cleaning and shaping of the canal system. Cleaning and shaping means the removal of the entire pulpal tissue from the canal, so that there will be no residue left of any vital structure, that may cause any painful or infectious condition for the future. Some times there occurs difficulty in cleaning as well as shaping of the root canal in the posterior tooth or teeth, where the anatomy of the root is some what curved, and there occur difficulty in removing the vital tissue along with difficulty in achieving the accurate working length of the tooth. In this type of situation use of nickel titanium single file system is quite beneficial.

Materials, 2022

The current study aimed to compare the F1 endodontic instruments from five different heat-treated rotary systems regarding their design, metallurgical properties, and mechanical performance. Five F1 root canal shaping instruments (ProTaper Gold [PTG], Premium Taper Gold, Go-Taper Flex, EdgeTaper Platinum, and Super Files Blue)—plus, a conventional ProTaper Universal (PTU)—which were evaluated regarding their design, nickel/titanium ratio, phase transformation temperatures, microhardness, cyclic fatigue, and torsional and bending strengths. Mood's median test was used for the statistical comparison with a significance set at 5%. The instruments were similar regarding the nickel/titanium ratio and overall design. Go-Taper Flex had the closest transformation temperatures to PTG. PTU and Go-Taper Flex had the highest microhardness (408.3 and 410.5 HVN). The time to fracture of Super Files Blue was three and seven times higher than PTG and PTU, respectively. No difference was observe...

International Journal of Science and Research (IJSR)

Journal of Endodontics, 2014

We compared the effects of 6 different rotary systems on transportation, canal curvature, centering ratio, surface area, and volumetric changes of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging. Methods: Mesiobuccal root canals of 120 mandibular first molars with an angle of curvature ranging from 20 -40 were divided into 6 groups of 20 canals. Based on CBCT images taken before instrumentation, the groups were balanced with respect to the angle and radius of canal curvature. Root canals were shaped with the following systems with an apical size of 25: OneShape (OS) (MicroMega, Besancon, France), ProTaper Universal (PU) F2 (Dentsply Maillefer, Ballaigues, Switzerland), Pro-Taper Next X2 (Dentsply Maillefer), Reciproc (R) R25 (VDW, Munich, Germany), Twisted File Adaptive (TFA) SM2 (SybronEndo, Orange, CA), and WaveOne primary (Dentsply Tulsa Dental Specialties, Tulsa, OK). After root canal preparation, changes were assessed with CBCT imaging. The significance level was set at P = .05. Results: The R system removed a significantly higher amount of dentin than the OS, PU, and TFA systems (P < .05). There was no significant difference among the 6 groups in transportation, canal curvature, changes of surface area, and centering ratio after instrumentation. Conclusions: The 6 different file systems straightened root canal curvature similarly and produced similar canal transportation in the preparation of mesial canals of mandibular molars. R instrumentation exhibited superior performance compared with the OS, TFA, and PU systems with respect to volumetric change. (J Endod 2013;-:1-5)

Annals of Medical and Health Sciences Research, 2019

Background: Rotary biomechanical root canal preparation is usually associated with dentin micro-cracks. Aim: to assess and compare the effect of file systems manufactured with different Ni-Ti technologies on root dentin micro-cracking as a measure for integrity. Materials and methods: seventy single canalled premolar root specimens of equal length were divided into seven equal groups (n=10) according to the canal preparation system used. G1 (Protaper universal), G2 (Protaper next), G3 (Protaper gold), G4 (Vortex Blue), G5 (XP Shaper), G6 (Hand K- files) and G7 left unprepared (control). The specimens were thereafter horizontally sectioned at three levels from root apex and accordingly groups were subdivided into 3 subgroups. Subg1 (3 mm), subg2 (6 mm) and subg3 (9 mm). The root sections were dye stained and examined under stereo light microscope for crack detection. The collected data were statistically analyzed. Results: Only group 4 & group 5 (single-file rotary groups) were compa...

Quintessence International, 2010

The introduction of nickel-titanium (Ni-Ti) to endodontics almost two decades ago 1 has dramatically changed the way root canal preparation is performed, in both general and specialist practices. The perceived most significant advantage lies in the predictability with which a desired shape is achieved. 2 Possibly more important, the use of rotary instruments requires attention to detail, eg, regarding the efficacy of antimicrobial regimes that further contribute to successful endodontic therapy. Then, cases of varying degrees of difficulty can be successfully treated, with excellent long-term outcomes (Fig 1). Not every instrument system is suitable for every clinician, and not all cases lend themselves to rotary preparation, mainly because of varying degrees of experience and complexity. Moreover, rotary instruments may break rather unexpectedly; if they are cleaned and sterilized for reuse, issues of corrosion and persistent contamination may come into play. 3 Therefore, knowledge of both clinical guidelines for and metallurgical properties of Ni-Ti rotary instruments is critical for their successful use. 2,4,5 A recent survey indicated that US-based endodontists are knowledgeable about Ni-Ti instrument usage but are still concerned about issues such as breakage and the quality of the canal shape. 6 Therefore, this review is intended to summarize most recent trends in Ni-Ti technology, instrument design, and usage parameters. This is hoped to provide clinicians a knowledge base for evidence-based practice, thus maximizing the benefits from the selection of Ni-Ti rotary instruments for root canal treatments. NICKEL-TITANIUM METALLURGY AND MANUFACTURING Nickel-titanium alloy, first developed for the US Navy, 7 is in principle highly resistant against corrosion, and, more important, it is superelastic and has a shape memory. The latter two properties stem from an atomic arrangement that is different from conventional alloys such as stainless steel. The atoms in steel can move against each other by a small specific amount before plastic deformation occurs (Fig 2); in contrast, Ni-Ti exists reversibly in two conformations, martensite and austenite, depending on ambient temperature (see Fig 2a) and external tension (see Figs 2b and 2c).