Motaz Elsadat - Assistant Lecturer, Department of Endodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt.
Ashraf Refai - Full Professor, Department of Endodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt.
Taher Islam - Full Professor, Department of Endodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt.

Introduction: This study was directed to evaluate the effect of different operating temperatures on the change in working length when using the XP-endo shaper file. Methods: A total of ۲۰ plastic blocks with۱۶ mm curved canals were used in this study. The working length was adjusted to be ۱۵ mm using a customized Teflon stopper (۱۰mm in length) which was used with all files in the study. The preparation was done using the XP-endo shaper file (FKG, La Chaux-de-Fonds, Switzerland) according to the manufacturer’s instructions. The blocks were divided into ۲ groups: Group ۱: body temperature, Group ۲: room temperature. Pre and post instrumentation imaging of the blocks was done using the stereomicroscopy at ۸x. The images were superimposed to create a composite image on which the evaluation of working length change was done. Mann-Whitney U test was used to compare the change in working length in the two groups. Results: There was no statistically significant difference between the two groups (P ≤ ۰.۰۵). Conclusions: Within the parameters of this study, although both groups showed an increase in working length when using the XP-endo shaper file, the operating temperature did not have an effect.

Root canal preparation, Rotary files, Working length change, XP-endo shaper