Purpose: To compare the formation of micro-cracks after canal preparation performed with different single-file systems as One Shape, F6 SkyTaper, HyFlex EDM, WaveOne , Reciproc, and WaveOne Gold.
N= 84 human extracted mandibular central incisors (40–60 y)
•Teeth were selected and divided into 6 experimental groups (n = 12 teeth) and a control group (unprepared teeth):
- One Shape (group 1)
- F6 SkyTaper (group 2)
- HyFlex EDM (group 3)
- WaveOne (group 4)
- Reciproc (group 5)
- WaveOne Gold (group 6)
- Roots were then sectioned at 3, 6, and 9 mm from the apex, and the surface was observed under a stereomicroscope
Most highlighted Results:
- No cracks were observed in the control group.
- All the systems tested caused cracks, mainly in the apical section (3 mm). HyFlex EDM (33.3%) and WaveOne Gold (58.3%) showed fewer microcracks than other experimental groups (P < .01).
- however, no significant difference was found between them in crack formation (P > .05).
- There was no difference among the other experimental groups (P > .05).
The flexibility of nickel-titanium instruments because of heat treatment seems to have a significant influence on dentinal crack formation. Hy- Flex EDM and WaveOne Gold caused less microcracks than the other instruments tested.