Shaping ability of 2Shape and NeoNiTi rotary instruments in preparation of curved canals using micro-computed tomography

Abstract

Background Various systems of nickel-titanium (NiTi) instrument have long been commercially available. However, the preparation of narrow and curved root canals has always been challenging. The purpose of this study was to compare the shaping ability of two NiTi systems (2Shape and NeoNiTi) in severely curved root canals with different morphological patterns using micro-computed tomography (Micro-CT). Methods A total of 22 human extracted permanent teeth of mandibular first molars, with the exact mesial angle of curvature of 25 and 35 degrees, according to Schneider’s technique, were distributed randomly into two groups (group I: 2Shape, group II: NeoNiTi) based on the rotary system used (n = 22). The groups were subdivided into two subgroups corresponding to the angle of canal curvature (25° and 35°) (n = 11). Canals were scanned using Micro-CT pre- and post-preparation to assess the volume of dentin removed; canal transportation; and canal centering ratio at 3, 6, and 9 mm from the apex. The Mann–Whitney U test was utilized to determine any significant differences between the two systems. The level of statistical significance was set at p < 0.05. Results There was no significant difference between the two groups in volume of dentin removed; canal transportation; and centering ability for 25° and 35° canal curvatures at 3, 6, and 9 mm from the apex (coronal, middle, and apical) thirds (p > 0.05). At the middle third, the NeoNiTi group demonstrated a statistically significant increase in volume of dentin removed for 35° canal curvatures compared to the 2Shape group. Conclusion Within the limitation of our in vitro study, 2Shape and NeoNiTi systems with severely curved canals were confirmed to be relatively safe in preparation and to respect original canal anatomy. Nevertheless, NeoNiTi instruments produced more centered preparation and minimal canal deviation compared to the 2Shape system.

Canal transportation and centering ratio after preparation of curved canals: A comparative evaluation of cone-beam computed tomography and micro-computed tomography

“…In the current study, the magnitude of canal transportation following root canal instrumentation with 2Shape rotary system was lower than that reported in previous studies [30,31]. The centering ratio calculated in this study after root canal preparation was similar to that in a study by Nehme et al [31].…”

Pulp Volume Changes after Root Canal Preparation with Three Single Nickel Titanium Files Using Cone Beam Computed Tomography: A Randomized Clinical Trial

“…According to existing knowledge, the preparation of such canals leaves some canal surfaces unaffected (23) . Several studies have compared the pulp volume of various instruments; however, these studies compared variations based on the use of canals with more intricate anatomies rather than variations in the preparation procedure, as in the current study (24) .…”

Smear Layer Removal by 1% Phytic Acid after Root Canal Preparation with Three Different Rotary Systems

“…The instruments for all groups were discarded after three uses. The endodontic motor (X-smart, Dentsply Maillefer) was adjusted for each file corresponding to the instructions of manufacturer in crown-down order, which progressed with light apical pressure in a slow-in and slow-out motion [29]. After each file, the canals were irrigated with 2 mL 2.5% NaOCl for 1 min.…”