Effect of Canal Length and Curvature on Working Length Alteration with WaveOne Reciprocating Files

The article “Effect of Canal Length and Curvature on Working Length Alteration with WaveOne Reciprocating Files” by Elio Berutti, Giorgio Chiandussi, Davide Salvatore Paolino, Nicola Scotti, Giuseppe Cantatore, Arnaldo Castellucci and Damiano Pasqualini (J Endod 37[12]:1687–90; 2011] should have included this statement in the author information section: “Giuseppe Cantatore, Arnaldo Castellucci, and Elio Berutti declare that they have financial involvement (patent licensing arrangements) with Dentsply Maillefer with direct financial interest in the materials discussed in this article.” In addition, Dentsply provided some of the instruments used in this study." The authors regret this omission

Comparison of Conventional and New-generation Nickel-Titanium Files in Regard to Their Physical Properties

Introduction This study investigated the surface, fractured structure, and physicochemical properties related to cyclic fatigue in various nickel-titanium (NiTi) files.Methods Among a total of 10 groups of NiTi files, conventional NiTi files (ProFile [Dentsply Maillefer, Ballaigues, Switzerland] and K3 [SybronEndo, Orange, CA]) and new-generation NiTi files (ProFile Vortex [PV; Tulsa Dental Specialties, Tulsa, OK], Vortex Blue [VB; Tulsa Dental Specialties], and K3 XF [XF; SybronEndo, Orange, CA]) with the same tip diameter (ISO size 25) and 2 types of taper (0.04 and 0.06) were used in this study. Scanning electron microscopy of the file surface structure, differential scanning calorimetry, and cyclic fatigue resistance tests were conducted.Results Many mechanical grooves were recognized on the file surface. The surface in the ProFile group was extremely smooth compared with that observed for the other files. Many shallow hollows besides mechanical grooves were noted on the surface in the XF group. A smooth curve was observed in the ProFile, K3, and PV groups. Defined peaks in differential scanning calorimetry were observed in the VB and XF groups. The 0.04 taper files exhibited a statistically higher number of cycles to fracture than the 0.06 taper files in all groups (P <.05). Cracks along the mechanical grooves were observed in the NiTi files, with the exception of the XF group. The start of cracking was detected at U-shape sites in the ProFile group, the cutting edge in the PV and VB groups, and radial islands in the K3 and XF groups.Conclusions The present findings suggest that new-generation NiTi files are not necessarily improved compared with conventional files

Dynamic properties of nickel-titanium instruments

Deposited with permission of the author. © 1997 Boonrat Sattapan.Root canal preparation in narrow, curved canals is a challenge even for experienced endodontists. Recently nickel-titanium (NiTi) hand files have played an important role in root canal preparation, particularly in curved root canals. Nickel-titanium endodontic instruments were first investigated in 1988 by Walia et al. who found that NiTi files have two to three times more elastic flexibility in bending and torsion, as well as superior resistance to torsional fracture compared with similar stainless steel files