Abstract: Objective: To compare the canal transportation and preparation efficiency of ProGlider and PathFile to prepare the MB2 of maxillary molar.Methods: 63 teeth with MB2 were obtained from 120 extracted maxillary molars in vitro using CBCT scanning.The MB2 was examined after opening the pulp chamber, and 42 teeth with MB2 were obtained.They were randomly divided into two groups.The root canals were prepared with ProGlider and PathFile, respectively.The preparation time was recorded.CBCT scanning was performed before and after preparation to evaluate the root canal transportation and centering ratio at 3, 5, and 7 mm from the apex and the most curved point.Results: The preparation time of ProGlider was significantly shorter than PathFile.There was no significant difference in mean transportation value between two groups at 3 mm and 7 mm levels.But ProGlider showed a significantly lower mean transportation value than PathFile at 5 mm levels and the most curved point.There was no significant difference in the centering ability between two groups at 3 mm, 5mm and 7 mm levels.But ProGlider showed a significantly better centering ability than PathFile at the most curved point.Conclusion: Both ProGlider and PathFile could prepare MB2 of maxillary molar efficiently and show good centering ability.The shaping ability of ProGlider was better than PathFile at the most curved point.

Key words: Glide path files, Maxillary molar, Canal transportation, Root canal preparation