This study aimed to compare the ProTaper Universal (PTU) system with 6 replicalike instruments regarding instrument design, mechanical performance and alloy characteristics.
New rotary instruments (size 20/.07v) of PTU and 6 replicalike systems (EdgeTaper, U-Files, Go-Taper Universal, Super Files, Multitaper, Pluri Taper) (n=329) were selected and evaluated regarding their design, mechanical performance, and metallurgical characteristics. Results were compared by using nonparametric Mood’s median test and one-way ANOVA with significance level set at 0.05.
Overall, replicalike instruments were similar to the PTU regarding design, maximum torque to fracture (P>.05), and ratio of nickel and titanium elements. Scanning electron microscopy revealed differences in the geometry of the tip and finishing surfaces. Time to fracture of Go-Taper Universal (50.0s) was similar to the PTU (44.0s) (P>.05), but U-File (63.5s), Edge Taper (87.5s) and Super Files (130s) showed significantly higher values (P<.05). The highest maximum torque was observed in the Super Files instrument (P.05). The angle of rotation before rupture of Multitaper (574º) and Pluri Taper (481º) were higher than the PTU (354º) (P<.05). Differential scanning calorimetric analysis showed clear differences on the transformation temperatures among the tested instruments. R-phase start and finish of PTU were 11.0ºC and -18.0ºC, respectively.
Overall, replicalike instruments were similar to the PTU regarding the torsional resistance, the geometric design and the near equiatomic proportions of nickel and titanium elements. In 3 out of 4 mechanical tests the EdgeTaper (torque, angle of rotation and bending load) and Go-Taper Universal (time to fracture, torque and angle of rotation) were similar to PTU.

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