Comparison of apical debris extrusion of different generation nickel-titanium instrument systems

BACKGROUND AND AIM

The aim of this study is to evaluate the apical debris extrusion amounts and preparation times of four different nickel-titanium systems with a similar cross-section design-Mtwo, RECIPROC, RECIPROC blue, and VDW.ROTATE.

MATERIALS AND METHODS

Eighty human mandibular central incisors were divided into four equal groups (n = 20). The test apparatus was inserted into an assembly that provided root canal temperature. Preparation times were recorded using a stopwatch, and the amount of extruded debris was collected in pre-weighed Eppendorf tubes. After drying, the net amount was determined by subtracting the previously measured Eppendorf tube weights from the total weight.

RESULTS

The Mtwo had the largest amount of debris, but there was no significant difference among the other groups. The VDW.ROTATE completed the preparation in a significantly shorter time than the RECIPROC blue and Mtwo.

CONCLUSION

Compared to other files, the Mtwo sequence produced significantly more debris and required significantly more time to complete the whole root canal preparation.

Comparison of the cyclic fatigue resistance of hyflex EDM, vortex blue, protaper gold, and onecurve nickel-Titanium instruments

Objective

This in vitro study aimed to compare the cyclic fatigue resistance of HyFlex EDM (HEDM), Vortex Blue (VB), ProTaper Gold (PG), and OneCurve (OC) nickel-titanium (NiTi) instruments.

Materials and Methods

About 12 HEDM (25/.~), 12 VB (25/.06), 12 PG (25/.08), and 12°C (25/.06) instruments were included in this study. All the instruments were tested with a 60° angle of curvature and a 3-mm radius of curvature. All the instruments were utilized until fracture occurred, and then the number of cycles to failure (NCF) was calculated. The data were analyzed statistically using Kruskal-Wallis H and Mann-Whitney U-tests. The statistical significance level was set at P < 0.05.

Results

HEDM instruments had the highest cyclic fatigue resistance among all the other instruments (P < 0.05). The OC instruments had a significantly higher fatigue resistance than the PG and VB instruments (P < 0.05); however, there was no significant difference between PG and VB instruments in the NCF (P > 0.05).

Conclusion

Within the limitations of this in vitro study, it was found that the cyclic fatigue resistance was higher for the HEDM instruments than for the VB, PG, and OC instruments.