Abstract:

Objective To investigate the shaping performance and safety of the WaveOne Gold single-file system in the instrumentation of curved root canals using three-dimensional （3D） digital assessment. Methods From March 2021 to March 2025， 84 extracted single-rooted permanent teeth with canal curvature angles ranging from 20° to 40°， confirmed by cone-beam computed tomography （CBCT）， were selected. The specimens were randomly assigned to two groups： a control group （n = 42）， prepared with the ProTaper Universal system， and an experimental group （n = 42）， prepared with the WaveOne Gold single-file system. Preparation time， canal transportation （at 1， 3， and 5 mm from the apex）， changes in canal volume and surface area， alteration in canal curvature， and apically extruded debris were compared between the groups. Results The preparation time was significantly shorter in the experimental group compared to the control group （P < 0.05）. Canal transportation values at 1， 3， and 5 mm from the apex were significantly lower in the experimental group （P < 0.05）. Furthermore， the increases in canal volume and surface area were significantly less pronounced in the experimental group （P < 0.05）. While no significant difference in initial canal curvature was observed between the groups （P > 0.05）， both groups exhibited a reduction in curvature after instrumentation； however， this change was significantly smaller in the experimental group （P < 0.05）. Additionally， the amount of apically extruded debris was significantly lower in the experimental group than in the control group （P < 0.05）. Conclusion Based on 3D digital evaluation， the WaveOne Gold single-file system demonstrates superior efficiency and safety for instrumenting curved root canals. It significantly reduces preparation time， minimizes canal transportation and apical debris extrusion， and better preserves the original canal curvature compared to the ProTaper Universal system.

Key words: curved root canal, WaveOne Gold single-file system, three-dimensional digital evaluation, canal transportation, apical debris extrusion