Figure 3.

Representative longitudinal and lateral aspects of the fracture fragments from the RTL method (left column; A, C, E, and G) and STL method (right column; B,D,F and H) (A, B, E and F; HyFlex EDM, C, D, G and H; V-Taper2). Specimens from the RTL method show rare unwinding near the fracture area (A and C; dotted box), while the specimens from STL method show typical features of unwinding (B and D; closed white arrows). The magnified aspects (E and G from A and C respectively) from the specimens of RTL method show irregular and catastrophic aspects (*) with some cracks without unwinding, while the magnified aspects (F and H from B and D respectively) had clear cut end. Especially, the specimen (G) from VT2 show the longitudinal microcracks (open white arrows).