Evaluation of the Shaping Ability of Three Thermally Treated Nickel–Titanium Endodontic Instruments on Standardized 3D-printed Dental Replicas Using Cone-Beam Computed Tomography

Laura Orel,Luminita-Maria Nica,Florin Topala,Virgil-Florin Duma,Roxana-Maria Talpos-Niculescu,Cosmin Sinescu,Oana-Alexandra Velea-Barta,Meda-Lavinia Negrutiu,Razvan Mihai Horhat,Andreea-Simona Boscornea-Pușcu,Dan-Dumitru Vulcanescu

doi:10.3390/medicina57090901

Abstract

Background and Objectives: The aim of the present study is to compare the efficacy of three root canal preparation systems in the shaping of 3D-printed root canal replicas of single rooted teeth. Materials and Methods: Sixty 3D-printed root canal replicas were produced and divided into three groups, each consisting of twenty samples. Each group was shaped with a different instrument: Reciproc Blue R25/08 (VDW GmbH, Munich, Gemany), WaveOne Gold Primary 25/07 (Dentsply Sirona, Ballaigues, Switzerland), and ProTaper Gold F2 25/08 (Denstply Sirona). To ensure the reproducibility of pre- and post-operative CBCT images of the root canals, the endodontic printed replicas were placed in a mould of silicon impression material. A cone-beam computed tomography (CBCT) software was used to compare pre- and post-instrumentation images collected at three levels of the root canal length: 3, 6, and 9 mm from the apical foramen. The amount of transportation, centring ability, and curvature angle after shaping were evaluated for each system. The results were statistically analysed and compared using one-way analysis of variance (ANOVA). Results: Regarding the transportation of the root canal after shaping, significant differences between groups at 3 mm (p = 0.010721) and 6 mm (p = 0.000046) were recorded in the mesio-distal direction, while in the bucco-lingual significant differences were only observed at 6 mm (p = 0.000554). Reciproc Blue removed more dentin from the mesial and buccal wall of the root canal. When evaluating the centring ability of the three systems, significant differences were observed between the groups at the level of 9 mm (p = 0.037258) in the mesio-distal direction, and at the level of 6 mm (p = 0.038197) in the bucco-lingual direction. Significant differences of the canal curvature angle after shaping were also observed between groups (p = 0.000001). Reciproc Blue straightened the curvature the most, while ProTaper Gold the least. Conclusions: All systems produced minor root canal transportation. No instrument was able to achieve a perfect centring preparation of the root canal. All systems produced a small degree of root canal straightening.

Highlights

It is well-known that a straight root canal is an exception rather than a normal situation in human teeth, as most root canals have one or multiple planes curvatures throughout their length [1]
This is the reason the aim of the present study is to assess the efficiency of endodontic shaping techniques on standardized dental replicas, using two systems with reciprocating motion: Reciproc Blue (RB) (VDW GmbH, Munich, Germany) and WaveOne Gold (WOG)
The present study revealed statistically significant differences in the mesio-distal direction at 3 mm, where Reciproc Blue removed more resin from the mesial side of the replica, from the external part of the curvature of the root canals, in comparison to WaveOne Gold and ProTaper Gold

Summary

Introduction

It is well-known that a straight root canal is an exception rather than a normal situation in human teeth, as most root canals have one or multiple planes curvatures throughout their length [1]. One of the main objectives in shaping the root canal system is to achieve a continuous tapered preparation, while maintaining its original morphology. In narrow and curved root canals, this is still a major challenge in current practice [3]. Achieving an ideal form after complete root canal shaping is challenging for endodontists and requires a thorough knowledge of the internal anatomy of teeth, of the properties of endodontic instruments, and of their cutting action [4]. The continuous development of nickel–titanium (NiTi) mechanical instruments and the improvements of the alloys’ properties makes current root canal instrumentation easier, faster, and more predictable [5,6,7]. Many shaping NiTi instruments use various structural designs to reduce the operational errors and to achieve predictable root canal preparations. The aim of the present study is to compare the efficacy of three root canal preparation systems in the shaping of 3D-printed root canal replicas of single rooted teeth

Objectives

Methods

Discussion

Conclusion