(PR052) Effect of Multiple Pressure Cooker Sterilization Cycles on Cyclic Fatigue of DCTaper Rotary NiTi Files

Introduction: In an austere environment, where unconventional sterilization methods are occasionally required, rotary files may be subjected to multiple sterilization cycles prior to use. Although heat-treated nickel titanium (NiTi) rotary files often come pre-sterilized from the manufacturer, the effect of additional exposures to pressure cooker sterilization on the cyclic fatigue of DCTaper NiTi rotary files is unknown. This study aimed to determine the effect of multiple pressure cooker sterilization cycles on the time to separation (TTS) for DCTaper files used in a simulated curve.

Methods: 180 size 20/v06 DCTaper files were randomly divided into 4 groups (n=45): files exposed to one (S1), three (S3), or five (S5) pressure cooker sterilization cycles and files directly from the manufacturer (C) as a control. Files were rotated at 500 rpms in a jig, simulating a 60-degree curvature and 6 mm radius and TTS was recorded. Results were analyzed using an ANOVA and the Tukey post hoc test with significance declared at p<0.05.

Results: The average TTS for the groups C, S1, S3, and S5 were 46.7, 44.9, 42.1, and 45.1 seconds, respectively. There was a moderate difference between the control and sterilized groups, but no significant pairwise differences (all p>0.05). No evidence for a linear relationship between sterilization cycles and TTS was found (p=0.66).

Conclusion: Within this study’s limitations, subjecting unused DCTaper files to 1, 3, or 5 sterilization cycles has no effect on TTS.