Micro‐ <scp>CT</scp> Evaluation of the Shaping Outcomes of Different Instruments in Oval‐Shaped Maxillary Premolar Canals

This study evaluated four file systems (WaveOne Gold, Reciproc Blue, ProTaper Next and TruNatomy) for their shaping efficacy in oval-shaped maxillary premolar root canals using micro-CT. Twenty-four extracted premolars, each with two roots, were randomly divided into four groups (n = 6 teeth/group) and instrumented following manufacturer guidelines. Pre- and post-instrumentation micro-CT scans were performed. Key parameters analysed included unprepared canal surface area (% Un-PrepCA), changes in canal area and volume (ΔCA, ΔCV and their percentages), canal transportation and centring ability. Statistical significance was set at p < 0.05. While no significant differences were found in transportation, centring ability or most 3D parameters (ΔCA, ΔCV and ΔSMI), the TRN group exhibited a significantly higher % Un-PrepCA. Conversely, the WOG group achieved a significantly greater % ΔCA compared to TRN and PTN. All systems performed comparably without procedural errors; TRN resulted in the least canal wall contact, while WOG provided the largest prepared canal area.