Finding appropriate nickel‐titanium instruments for lingual canals in mandibular first premolars with two canals: A micro‐CT study

Abstract

Background: To nd appropriate Nickel-Titanium instruments for lingual canals in mandibular rst premolars with two canals.Methods: A total of 42 extracted mandibular rst premolars with two canals were selected after micro-CT scanning. The teeth were matched and divided into three groups, and three types of Nickel-Titanium instruments (M3, HyFlex CM and XP-endo Shaper) were used to prepare the lingual canals of the sample teeth. After instrumentation, micro-CT scanning was used again to reconstruct the three-dimensional (3D) teeth model, and then it was geometrically aligned with the original model before instrumentation. Two-dimensional (2D) and three-dimensional parameters of teeth models were measured to evaluate the ability of cleaning and maintaining the original canal shape by the three different instruments.Results: Compared with HyFlex CM and XP-endo Shaper, the apical transportation of M3 was signi cantly greater within the apical 3 mm (P < 0.05), while there was no signi cant difference between HyFlex CM and XP-endo Shaper (P > 0.05). There was no signi cant difference in centering ability among three types of instruments (P > 0.05). In general, HCM group and XPS group performed better than M3 group in the 2D and 3D analysis (P < 0.05).Conclusions: Preparation of the lingual canal in mandibular rst premolar was more challenging than that of the main buccal canal. All the three nickel-titanium instruments are safe for canal preparation, and generally, the HyFlex CM and XP-endo Shaper performed better than the M3.