(PO142) Relative Preservation of Root Canal Geometry When Using Two Rotary File Systems

Abstract: A maxillary molar 3D printed model (TrueTooth 3-01, Plan B Dental) was used to study the effect of the location of canal curvatures on the relative performance of NiTi rotary files on canals with an apical vs. a mid-root curve, represented respectively by mesio-buccal (MB) and disto-buccal (DB) canals. Replicas were imaged by micro-computed tomography (17µm voxel resolution), followed by the creation of glide paths using #10 and #15 size K-files. MB1 and DB canals were instrumented with either Vortex Blue (Dentsply Sirona, n=4) or ZenFlex (Kerr Dental, n=4) files to a #35/0.04 ("standard" instrumentation) followed by widening to a #40/0.04 size ("wider" instrumentation). Imaging by micro-CT (sets A and B) was performed after each of these steps. The instrumented replicas were digitally registered to an uninstrumented one at a standard orientation, after which measurements of root canal transportation from 1-7 mm from the apex were made. Transportation values were not significantly different between systems in MB canals but were overall significantly higher (42-65% average, p < 0.05) for Vortex Blue files in DB canals in both standard and wider protocols. The location of the curve can be important for studying the relative performance between different file systems with similar apical geometry. The use of 3D-printed replicas can help in acquiring statistically robust relevant data from a relatively low number of specimens.