Impact of Varying Amplitudes of Upward and Downward Motion on the Torque/Force Generation, Canal-Centering Ability, and Cyclic Fatigue Resistance of Nickel–Titanium Reciprocating Instrument
The optimal amplitude of pecking motion during nickel–titanium rotary root canal instrumentation remains unclear. This study evaluated how different pecking amplitudes influence the force/torque generation, canal-centering ability, and cyclic fatigue resistance of the Reciproc Blue R25 instrument. T...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/1/288 |
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| Summary: | The optimal amplitude of pecking motion during nickel–titanium rotary root canal instrumentation remains unclear. This study evaluated how different pecking amplitudes influence the force/torque generation, canal-centering ability, and cyclic fatigue resistance of the Reciproc Blue R25 instrument. Thirty J-shaped resin canals were instrumented with Reciproc Blue using automated instrumentation and a torque/force sensing device with an up-and-down speed of 50 mm/min and varying pecking amplitudes: Group S (1 s apically, 0.5 s coronally), Group M (2 s apically, 1 s coronally), and Group L (4 s apically, 2 s coronally) (<i>n</i> = 10 each). Force/torque were recorded, and canal-centering ratios were determined. In a dynamic cyclic fatigue test, the Reciproc Blue instruments were rotated in a curved metal canal with 1 mm or 3 mm back-and-forth motions (<i>n</i> = 10 each). Group L exhibited significantly greater maximum downward force and cumulative upward (screw-in) force than Group S (<i>p</i> < 0.05), but torque was not significantly different across groups. Groups M and L exhibited a significantly smaller canal-centering ratio than Group S (<i>p</i> < 0.05). Pecking at 3 mm led to a significantly longer time to fracture and shorter fragment lengths than 1 mm pecking (<i>p</i> < 0.05). In the Reciproc Blue instrumentation, higher pecking amplitude improved canal-centering ability and cyclic fatigue resistance while increasing upward and downward forces. |
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| ISSN: | 2076-3417 |