Micro‐Computed Tomography and Scanning Electron Microscopy Comparisons of Two Nickel–Titanium Rotary Root Canal Instruments Used With Reciprocating Motion

Abstract

The single-file root canal instrumentation technique using reciprocating motion has been gaining concern. Therefore, the purpose of this study was to compare the shaping ability of single ProTaper F2 file and WaveOne Primary file when they were used in the curved root canal with reciprocation motion and to investigate the durability of the file after use with a scanning electron microscopy (SEM). Changes in structure model index (SMI), root canal volume, curvature, surface area, and degree of transportation were measured from the cross-sectional images of the prepared canals using the micro-CT system with an isotropic resolution of 16 μm. Results showed that there were no differences in the changes of root canal volume, surface area, and SMI between the two file groups after the preparation (p > 0.05). The ProTaper group showed a curvature straightening value of 25.45 ± 12.51%, while the WaveOne group showed 27.30 ± 10.91%, and there was no statistically significant difference (p > 0.05). The transportation values between the two groups showed no significant differences (p > 0.05). SEM revealed that 60% of ProTaper files showed initiation of microcracks on the surface while those were detected on the only one WaveOne file. The single-file technique using either WaveOne Primary or ProTaper F2 can be safely used under each reciprocating motion without creating an increased apical transportation in curved canals. However, the metallurgic property resists cyclic fatigue was more favorable with WaveOne under the scanning evaluation.

A Micro–computed Tomographic Assessment of Root Canal Preparation with a Novel Instrument, TRUShape, in Mesial Roots of Mandibular Molars

“…For all assessed variables, comparison data are available (eg, the reported amount of removed dentin volume varied from 0.5 to 3.5 mm 3 [15,16], with the majority of the studies showing values in the range of 1-2.5 mm 3 [17][18][19][20][21][22][23]). These sizable differences may be explained by differences in initial canal anatomy and selecting the volume of interest as much as the preparation technique itself.…”

“…It has been shown that severe canal transportation (eg, strip perforation) is related to inferior outcomes (3); hence, numeric comparison of canal transportation is frequently done in the assessment of preparation quality. A variety of methods have been used in mCT-based studies (20,23,(29)(30)(31) (eg, vector-based and trigonometry-based numbers). Because these assessments provide partial scores, including the direction of transportation, it is again difficult to directly compare the results of the present study.…”

Apical Extrusion of Debris in Flat-oval Root Canals after Using Different Instrumentation Systems

“…The WaveOne (WO, Dentsply Tulsa Dental) is a reciprocating system that includes 3 instruments with an apical concave triangular cross-section and reverse cutting blades (14). These instruments were specifically designed to minimize the risk of instrument fracture and oscillate at approximately 350 rpm with 30 clockwise and 150 counterclockwise rotation angles (15). It seems that reciprocating systems tend to push more debris and irrigants toward the periapical tissues than rotary systems (16).…”

Cyclic Fatigue Resistance of Three Single-use NiTi Instruments after Immersion in Sodium Hypochlorite

“…Due to the fact that the counterclockwise angle is greater than the clockwise one, it is claimed that the instrument continuously progresses toward the terminus of the root canal. Both instruments have been evaluated in preliminary studies 22,23,26,[28][29][30][31][32] and the results regarding lifespan, cyclic fatigue resistance, shaping ability and cleaning efficiency were satisfactory.…”

“…27 The new single-use systems have been introduced to shape root canals with only one file: this technique simplification allows saving time and cost for endodontic treatment. 31 However, to shape root canals with only one file, the instrument will be subject to a great deal of stresses, both torsional and cyclic (bending) fatigue. This instrument is not used for further canals and not requires thermal sterilization in autoclave, so it will be not exposed to other stresses.…”