Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2017-11-24, 11:00:53 | version 1.38.0
| study defects after preparation Dentinal defects after root canal preparation with HyFlex EDM, WaveOne Gold and ProTaper Gold: Light-emitting Diode Assessment Author: Drs. Taha Özyürek, Mustafa Gündo ar, Gül ah Uslu & Koray Yılmaz, Turkey Introduction Vertical root fractures are one of the most fre- quent complications seen on teeth having endo- dontic treatment, and generally result in the extrac- tion of tooth (Haueisen et al. 2013). The root canal treatment procedures may cause dentinal stress and consequently dentinal cracks. The emerging dentinal fractures may transform into vertical root fractures under functional loads (Barreto et al. “The root canal treatment procedures may cause dentinal stress and consequently dentinal cracks.” 2012). The physical and mechanical properties of nickel titanium (NiTi) rotary file systems my affect the incidence of cracks on dentinal surface (Adorno et al. 2011). Moreover, the type of movement used in shaping the root canals may also influence the inci- dence of dentinal defects. Liu et al. (2013) have re- ported that a continuous rotational movement causes more dentinal defects than reciprocation movement, while Bürklein et al. (2013) have re- ported that reciprocation movement causes more dentinal defects. (WOG; Dentsply Maillefer). While maintaining the reciprocation movement of the file, its cross-sec- tion, dimensions and geometry were changed. The cross-section of the file was altered to a parallelo- gram, having two cutting edges. Moreover, the off-centre design that ProTaper Next (Dentsply Maillefer) files have is used in WOG files too. The most significant change in files is the Gold heat treatment method. Gold heat treatment is based on reversing the M-Wire technology employing the pre-production heat treatment, and by heating the file after production and then slowly cooling it. The manufacturer company claims that this new heat treatment increases the flexibility of files (WaveOne Gold Brochure). Another NiTi rotary file system made using the Gold heat treatment procedure is the recently intro- duced ProTaper GOLD (PTG; Dentsply Maillefer) sys- tem. Similar to ProTaper Universal (PTU; Dentsply Maillefer) system, this model consists of three shap- ing (SX, S1 and S2) and five finishing (F1, F2, F3, F4 and F5) files. PTG uses the continuous rotation movement at the same torque and speed settings with PTU, but the manufacturer claims that PTG files are two times more resistant to the cyclic fatigue under favour of flexibility offered by the Gold alloy (ProTaper Gold Brochure). From the aspect of met- allurgical character, PTG NiTi files have not only the 2-stage specific transformation feature but also high Af temperature similar to controlled memory (Shen et al. 2011). WaveOne (WO; Dentsply Maillefer) NiTi single- file system was recently modified to WaveOne Gold Recently, the patented treatments have been in- volved in the innovative production of new HyFlex EDM files (HEDM; Coltène/Whaledent, Altstätten, 24 roots 4 2017