To evaluate the effect of continuous or reciprocating file rotary movement in instruments’ fracture, using one-file systems
Method:
Two one-file rotary endodontic systems, Reciproc (VDW) and WavewOne (Maillefer) and two multiple-file systems, Mtwo (VDW) and ProTaper (Maillefer), were used to shape curved simulated root canals in plastic blocks. Files from each system were used in continuous motion in a group of blocks and in reciprocating motion in another group. They were used in different resin blocks until fracture. Time until fracture and number of shaped canals were measured. Comparisons were analyzed with the --- test (p<0.05).
Result:
Number of prepared canals and average time until fracture (in minuts) were as follows in continuous and reciprocating motion respectively. Mtwo: 5, 17.00 and 14, 46.25; ProTaper: 11, 16.18 and 11, 37.82; Reciproc: 13, 82.08 and 12, 84.00; WaveOne: 11, 71.91 and 12, 76.75.
Conclusion:
One-file systems showed longer working time until fracture in both continuous or reciprocating movement. Multiple-file systems improve it behavior in reciprocating motion. No significant differences were found in the number of shaped canals between one-file systems, but Mtwo showed a significant higher number of instrumented blocks in reciprocating motion when compared with continuous motion or with ProTaper in both movements.