Shaping Ability of Rotational and Reciprocating Nickel-Titanium Endodontic File Systems: A Micro-Computed Tomographic Evaluation

Objectives: This study aims to investigate the accuracy of the adaptation and the chance of abberation of the nickel-titanium endodontic files to root canal anatomy during root canal treatment.

Methods: In this study, micro-computed tomography (microCT) images were analysed to evaluate the shaping ability of a rotational (ProTaper NEXT, Dentsply, Germany) and two reciprocal (WaveOne Gold, Dentsply, Germany and Reciproc, VDW GmbH) NiTi endodontic file systems.
The mesiobuccal and distobuccal canals of extracted human maxillary molars (n = 36) were used with the following inclusion criteria: no or minimal caries extent limited to coronal of cemento-enamel junction (CEJ); un-treated root canals; complete apexification; bi-furcated roots. The glide path was created to working length using manual #10, 15 K-files followed by Proglider (Dentsply), and irrigated throughout with 3.25% sodium hypochloride.
Each group (n = 18) was assigned with one of three different NiTi systems at either rotational or reciprocational movement for the root canal shaping and the total preparation times were recorded.
The microCT images (SkyScan1172, SkyScan, Belgium) were taken before (pre) and after (post) the root canal shaping (100kV source-voltage, 100mA source-current, 0.5mm aluminium-filter, 4-m resolution, 180°-rotation around mid-vertical axis, 0.4 single-rotation step, 4mm pixel-size). The images were reconstructed using NRecon1.6.2.0 (SkyScan), and data for each root extracted with 3000-vertical-sections.
The total volumetric change among pre and post groups of dentinal canal walls were determined by superimposition using Volume of Interest (VOI) in Mimics software (Materialise, Geneva). The degree of canal-transportation at cervical, middle and apical thirds was evaluated.
Statistical analysis were performed by using SPSS 22.0 software (IBM).
Results: The total volume change after the preparation was not significant between the NiTi file systems (P >.05). A statistically significant time was needed when the multiple files were used (P <.05).
Conclusions: Less number of the file used for root canal preparation, resulted less canal preparation time without the significant volume change of the root canals.