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.
Keywords: Apical foramen; Apical foramen enlargement; Endodontics; Root canal therapy Tooth apices..