OBJECTIVES: To examine the surface topography of intact WaveOne (WO; Dentsply Sirona Endodontics) and WaveOne Gold (WOG; Dentsply Sirona Endodontics) nickel-titanium rotary files and to evaluate the presence of alterations to the surface topography after root canal preparations of severely curved root canals in molar teeth. MATERIALS AND METHODS: Forty-eight severely curved canals of extracted molar teeth were divided into 2 groups (n = 24/each group). In group 1, the canals were prepared using WO and in group 2, the canals were prepared using WOG files. After the preparation of 3 root canals, instruments were subjected to atomic force microscopy analysis. Average roughness and root mean square values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way analysis of variance and post hoc Tamhane's tests at 5% significant level. RESULTS: The surface roughness values of WO and WOG files significantly changed after use in root canals (p < 0.05). The used WOG files exhibited higher surface roughness change when compared with the used WO files (p < 0.05). CONCLUSIONS: Using WO and WOG Primary files in 3 root canals affected the surface topography of the files. After being used in root canals, the WOG files showed a higher level of surface porosity value than the WO files.
Dental Pulp Cavity ; Microscopy, Atomic Force ; Molar ; Porosity ; Root Canal Preparation ; Tooth

Objectives: This study aims to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium (NiTi) rotary files at body temperature. Materials and Methods: In total, 80 VDW.ROTATE (25/0.04), TruNatomy (26/0.04), 2Shape (25/0.04), and HyFlex CM (25/0.04) NiTi rotary files (n = 20 in each group) were subjected to static cyclic fatigue testing at body temperature (37°C) in stainless-steel artificial canals prepared according to the size and taper of the instruments until fracture occurred. The number of cycles to fracture (NCF) was calculated, and the lengths of the fractured fragments were measured. The data were statistically analyzed using a 1-way analysis of variance and post hoc Tamhane tests at the 5% significance level (p < 0.05). Results: There were significant differences in the cyclic fatigue resistance among the groups (p < 0.05), with the highest to lowest NCF values of the files as follows: VDW.ROTATE, HyFlex CM, 2Shape, and TruNatomy. There was no significant difference in the lengths of the fractured fragments among the groups. The scanning electron microscope images of the files revealed typical characteristics of fracture due to cyclic fatigue. Conclusions The VDW.ROTATE files had the highest cyclic fatigue resistance, and the TruNatomy and 2Shape files had the lowest cyclic fatigue resistance in artificial canals at body temperature.

Objectives: This study aims to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium (NiTi) rotary files at body temperature. Materials and Methods: In total, 80 VDW.ROTATE (25/0.04), TruNatomy (26/0.04), 2Shape (25/0.04), and HyFlex CM (25/0.04) NiTi rotary files (n = 20 in each group) were subjected to static cyclic fatigue testing at body temperature (37°C) in stainless-steel artificial canals prepared according to the size and taper of the instruments until fracture occurred. The number of cycles to fracture (NCF) was calculated, and the lengths of the fractured fragments were measured. The data were statistically analyzed using a 1-way analysis of variance and post hoc Tamhane tests at the 5% significance level (p < 0.05). Results: There were significant differences in the cyclic fatigue resistance among the groups (p < 0.05), with the highest to lowest NCF values of the files as follows: VDW.ROTATE, HyFlex CM, 2Shape, and TruNatomy. There was no significant difference in the lengths of the fractured fragments among the groups. The scanning electron microscope images of the files revealed typical characteristics of fracture due to cyclic fatigue. Conclusions The VDW.ROTATE files had the highest cyclic fatigue resistance, and the TruNatomy and 2Shape files had the lowest cyclic fatigue resistance in artificial canals at body temperature.