The Shaping Effects of Three Nickel-Titanium Rotary Instruments in Simulated S-Shaped Canals

Abstract

The purpose of this study was to compare the shaping effects of three nickel-titanium rotary instruments, ProTaper, K3, and RaCe, with emphasis on canal transportation. Simulated canals with an S-shaped curvature in clear resin blocks were prepared with a torque-control, low-speed engine. Canals were prepared using the crown-down technique to the size of #30. Canal aberrations were assessed by comparing the pre- and postinstrumentation images under a stereomicroscope. ProTaper instruments caused greater widening of canals compared to K3 or RaCe. Furthermore, ProTaper files showed a tendency to ledge or zip formation at the end-point of preparation. These canal aberrations may be caused by ProTaper finishing files, which appear to be less flexible than other files of the same tip-size, because of their greater taper-size. These results suggest that nickel-titanium file systems including less tapered, more flexible instruments, like K3 and RaCe should be used in the apical preparation of canals with a complicated curvature.

Properties of Mechanical Endodontic Instruments and the Quality of the Simulated Canal Preparation

“…This is consistent with other studies [19,20]. This result could mean that some parts of the canal are cleaned too poorly, or others are overprepared, which is a result of file stiffness; in clinical conditions this can lead to the weakening of the root structure.…”

Comparison of cyclic fatigue and torsional resistance in reciprocating single-file systems and continuous rotary instrumentation systems

“…These instruments have a lower elasticity modulus than conventional stainless steel files and are therefore more flexible (2). This greater flexibility, combined with other favorable mechanical properties and high cutting efficiency, increases the safety and effectiveness of instrumentation of curved canals without causing deviation in the final preparation shape (2).…”

Süt Di̇şleri̇nde Ni̇kel Ti̇tanyum Döner Aletleri̇ni̇n Kullaniminin Değerlendi̇ri̇lmesi̇

“…58 Protaper'ın diğer sistemlere göre sertliğinin fazla olması azalmış kanal kurvatürü, artmış apikal transportasyon ve apikalde basamak oluşumu gibi durumlara neden olabilmektedir. Yoshimine ve ark 59 Protaper, K3 ve Race döner alet sistemlerini karşılaştır-dıkları çalışmalarında; Protaper sisteminin daha fazla dentin kaldırdığını, daha az taper'lı ve daha esnek olan K3 ve Race sistemlerinin kurvatürlü kanallarda tercih edilebileceğini bildirmişlerdir. Kuo ve arkadaş-ları 60 ise; Protaper aletlerinin süt dişlerinde güvenli ve etkili bir şekilde kök kanal tedavisinde kullanılabile-ceğini gözlemlemişlerdir.…”