Investigation of the efficacy of different Ni-Ti systems on acrylic blocks for correcting ledge formation

Abstract

Background The aim of this study was to compare the efficacy of K-type stainless steel hand instruments (Mani Inc. ), Fanta AF™ Ledge Correction (LC) (Fanta Dental), and Hyflex EDM (Coltene-Whaledent) for ledge correction, canal transport, centric ability, and shaping (preparation) time after an artificial ledge has been bypassed manually in highly curved canals using acrylic blocks. Methods Forty-two resin blocks, each with a radius of 5 mm (Endo Trainer Block, VDW) and an apical inclination of 55°, were used. Under stereomicroscope magnification, standard artificial ledges were created on acrylic blocks, and attempts were then made to eliminate them using hand instruments, FantaAF™ LC, and Hyflex EDM. Before and after images were obtained using a stereomicroscope and compared using Photoshop. Results Fanta AF™ LC and Hyflex EDM were found to be more effective for correcting ledges than hand instruments. The use of hand instruments resulted in the greatest transportation away from the canal curvature in the apical area. The canal shaping was completed in the shortest amount of time using Fanta AF™ LC, followed by HyFlex EDM and then the hand instruments. Conclusion In terms of centric ability, the order from best to worst is as follows: Fanta AF™ LC, Hyflex EDM, and hand instruments. After the ledge was manually bypassed with hand instruments in the root canals, Hyflex EDM and Fanta AF™ LC were found to be more effective than hand instruments in reshaping the previously unreachable region between the ledge and the foramen apical.

Endodontic Orthograde Retreatments: Challenges and Solutions

“…The main advantage of NiTi instruments consists of their increased taper and the possibility to rotate them at higher speeds, resulting in more effective management. 105 Despite this, not all NiTi instruments can be used for this purpose because of their metallurgical properties. The conditio sine qua non for their use is the martensitic crystallographic phase at the intracanal temperature, which allows them to be pre-bendable.…”

“… 106 Once the small NiTi instrument is pre-curved, the ledge is bypassed by manually inserting the NiTi rotary instrument and then rotated with an endodontic motor with up and down movements of 1mm of amplitude apically to the ledge. 105 Nevertheless, there are some alternatives to the above-mentioned techniques. Ünlü et al compared the effectiveness of a recently introduced NiTi instrument characterized by a bent tip with K-file in bypassing ledges, concluding that Fanta AF™ Ledge Correction instruments had higher performances in terms of centering ability, shaping ability and effectiveness.…”

“…Ünlü et al compared the effectiveness of a recently introduced NiTi instrument characterized by a bent tip with K-file in bypassing ledges, concluding that Fanta AF™ Ledge Correction instruments had higher performances in terms of centering ability, shaping ability and effectiveness. 105 Another tip is to induce martensitic crystallographic transformation of austenitic instruments by cooling their tip with the conventional cold pulp testing spry, so as to be pre-bendable and use them as described above. However, there are no articles in the literature describing this technique.…”