Comparison Between ProTaper Gold and EdgeTaper Platinum NiTi Rotary Files after Simulated Clinical Use

The objective of this study is to compare Torsional Force to Fracture (TFF) and angle of rotation to fracture of Edge Taper PlatinumTM (ETP) and ProTaper Gold (PTG) Nickel-Titanium (NiTi) rotary instruments in as-received condition, and after 1 and 3 simulated clinical uses.Methods: Two hundred simulated root canals (30-degree curvature) Endo-training blocs were randomly divided into two groups ( ETP and PTG). File sets consisted of SX, S1, S2, F1, and F2 files 25mm in length (N=10/size). Each set of files were used to prepare either one or three blocs under simulated clinical conditions per manufacturer instructions. Files were tested for mechanical properties per ISO 3630-1 guidelines by using a Torsiometer (Sabri Dental Enterprises, Inc, Downers Grove, IL). The values of peak torque (gm-cm) and angle rotation (°) were recorded for each file tested. Data were analyzed using ANOVA and Tukey-Kramer tests (p<.05). Results: Within each ETP and PTG group a significant (p<.05) lower TFF value was seen after 3 uses when compared to the as received condition and single use.  Between-groups there was a statistical significant difference in angle of rotation between ETP>PTG (SX, S1, and F2). There was no difference in TFF between ETP and PTG after 1 and 3 uses between each file system Conclusions: After single use the torsional resistance to fracture in both groups markedly decreased, multiple use of files is cautioned.  PTG and ETP have similar torsional resistance to fracture.