Micro-CT 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.