Apical preparation size after repetitive pecking to the working length using different endodontic file systems

Aim: The purpose of this study was to determine and evaluate the apical preparation size resulting from different pecking times to the working length (WL) with five different file systems. Materials and methods: Fifty standard simulated endodontic J-shaped blocks were instrumented using ProTaper NEXT (PTN), WaveOne (WO), WaveOne Gold (WOG), OneShape (OS) and the Self- Adjusting File (SAF) (n = 10) with different pecking times (1, 2 and 4) to the WL. For the SAF group, instrumentation was done till WL according to the time, i.e. 1, 3 and 4 min. On completion of each stage, silicone impression material was used to take canal impressions for comparison and evaluation of the apical size preparation, using a stereomicroscope. Two-way analysis of variance was applied to determine differences between groups and pecking times. Results: After four pecking times, a significant increase was observed in the apical diameter of four test groups compared to SAF (P < 0.05), which was not associated with increased apical preparation at all times. Conclusion: A greater apical enlargement occurs with increasing pecking times; however, SAF instrumentation exhibits the minimum changes in the apical preparation after 1, 3 and 4 min. WO, WOG and OS are able to prepare the apical size similar to their tip at a single peck to the WL.