Vertical root fracture resistance and dentinal crack formation of root canal-treated teeth instrumented with different nickel –titanium rotary systems: an in-vitro study

AbstractTo compare the vertical root fracture (VRF) resistance of root canal-treated teeth instrumented with four different nickel –titanium (NiTi) rotary file systems and examine the dentinal crack pattern and direction using a new classification. Eighty mature mandibular premolars were selected and decoronated, leaving 13 mm of the root. The root samples were mounted in acrylic resin and divided randomly into five groups o f different NiTi file systems: Group 1—control, Group 2—T-Pro, Group 3—HyFlex CM, Group 4—TG6 and lastly Group 5—ZenFlex. Samples in Group 2 and Group 3 were instrumented up to size 25/0.04, whereas Group 4 and Group 5 were instrumented up to size 25/0.06. Obturation was performed with AH Plus sealer and gutta-percha using single cone technique. Subsequently, all samples were subjected to occlusal compressive force until they were fractured. The force (N) needed to cause root fracture was recorded. The crack patterns and directions were also inspected under magnification and classifi ed using a new and simple classification. The highest (VRF) resistance was noted in the control group (453.15 ± 92.23 N), followed by T-Pro (387.43 ± 76.81 N), HyFlex CM (381.88 ± 52.73 N), ZenFlex (369.15 ± 89.41 N) and finally TG6 (346.05 ± 72.08 N), but there was no significant difference between T-Pro and HyFlex (P = 0.438). A significantly higher prevalence (P = 0.001) of Type 1 crack pattern was observed, especially in ...

Source: Odontology - July 16, 2021 Category: Dentistry Source Type: research