Evaluation of Foraminal Enlargement with Thermally Treated Nickel-Titanium Systems.

AIM AND OBJECTIVE: To evaluate morphologic changes in the main foramen after enlargement with four different systems. MATERIALS AND METHODS: One hundred and twenty canals (buccal of maxillary molars and mesial of mandibular molars) with patency and apical foramen ≤200 µm were included. These apical foramina were photographed and then randomly divided into four experimental groups, according to the ProDesign Logic (PDL), ProDesign R (PDR), twisted file adaptive (TFA), and WaveOne Gold (WOG) systems, all of which were composed of three sequential instruments (Glidepath, #25 and #35). Root canals were prepared 1 mm beyond the main foramen (n = 30). The specimens were photographed again to capture intermediate (#25) and final enlargement (#35) images. These were analyzed using an image software that allowed comparison of the enlarged area and shape of the main foramen. RESULTS: In the Intragroup comparison, the Friedman's test showed a statistical difference between each phase of foramen enlargement (p <0.05). In the intergroup comparison, the percentage of foramen enlargement showed statistically significant difference between Groups PDR and TFA only in the analysis from #25 to #35, with 42.88 and 67.34% of foramen area widening, respectively. Relative to the final foramen shape, 81.7% were observed to be circular, 17.5% oval, and 0.8% flattened. CONCLUSION: Our results showed that foramen enlargement allowed an increase in area, maintained the circular shape of the foramen in the majority of cases, irrespective of the system used, and was a feasible option for use during preparation of the root canal system.

Durability of Two R-Phase Rotary Systems used in the Mechanical Instrumentation of Dilacerated Root Canals.

AIM: This study was aimed to analyze, through an ex vivo test, the durability of two rotary systems used in curved root canals of extracted molars. MATERIALS AND METHODS: At first, 150 upper and lower molars were selected, presenting curvature at least in one of the root canals. They underwent access cavity and radiographed with a # 15 file into the canal to determine their maximum curvatures, classified as schneider. The teeth with one or more curved canals were included in this study. Finally, 120 curved root canals were statistically divided into six sets of 20 curved canals. Two rotatory systems, K3 XF (RCS sequence) and twisted file (Large Kit), both treatment R-Phase, were analyzed. Three kits were used for each system, each one instrumented one of the six sets of 20 curved canals. File deformations were noted, and the files were used until a fracture occurs or until completion of 20 canals preparation. Fractured files before the end of the instrumentation of the 20 canals were replaced, continuing the full instrumentation set. Statistical analysis was performed by analysis of variance (ANOVA) (p >0.05), and a qualitative assessment was also made. RESULTS: It was found that there was no statistical difference between the K3 XF and TF systems regarding fracture. CONCLUSION: There were no statistical differences between the K3 XF systems in the RCS sequence and the twisted file kit Large system, as to the number of instrumented conduits to the deformation or fracture. CLINICAL SIGNIFICANCE: The findings of this study reinforce that, it is necessary to choose files that support curved roots preventing accidents inside the root canal. Therefore, it is important for professionals to have knowledge and command of these protocols to obtain more satisfactory results.