Objectives: This study compared the accuracy of the guide-supported and the microscope-assisted fiber post removal systems by using the extracted teeth. These new idea and theory can be used by clinicians to remove fiber posts.
Methods: Twenty-eight human extracted premolars were randomly divided into the guide and microscope groups. After root canal treatment and fiber post restoration, the fiber posts were removed by using a digital guide and via microscope-assisted ultrasonic instrument, respectively. Mimics 10.0 was used to measure the deviation, and the accuracy of the two fiber post removal systems were compared.
Results: In the guide group, the apical vertical deviation was 0.99 mm±0.52 mm, the apical horizontal deviation was 0.75 mm±0.19 mm, the angle deviation was 2.32°±0.64°, and the volume loss was 8.09 mm3±1.42 mm3. In the microscope group, the apical vertical deviation was 0.44 mm±0.23 mm, the apical horizontal deviation was 0.23 mm±0.07 mm, the angle deviation was 0.64°±0.31°, and the volume loss was 15.25 mm3±3.94 mm3. No significant difference was found in the apical vertical deviation between the two groups (P>0.05), whereas the apical horizontal deviation, the angle deviation, and the volume loss were significantly different between the two groups (P<0.05).
Conclusions: The removal of fiber post supported by a digital guide helped reduce the volume loss of post-core restoration teeth, but its accuracy was lower than that of removal by using a microscope-assisted ultrasonic instrument.
目的: 通过离体牙模型对导板支持与显微镜辅助2种纤维桩拆除系统的精确度进行比较，为临床医师拆除纤维桩提供新思路和理论依据。方法: 将28颗人类离体前磨牙随机分为导板组与显微镜组，进行根管治疗及纤维桩修复治疗后，分别采用数字化导板与显微镜辅助超声器械进行纤维桩拆除。利用Mimics 10.0软件测量拆除后的偏差值，比较2种纤维桩拆除系统的精确度。结果: 导板组的尖端垂直偏差为0.99 mm±0.52 mm，尖端水平偏差为0.75 mm±0.19 mm，角度偏差为2.32°±0.64°，体积损失为8.09 mm3±1.42 mm3；显微镜组的尖端垂直偏差为0.44 mm±0.23 mm，尖端水平偏差为0.23 mm±0.07 mm，角度偏差为0.64°±0.31°，体积损失为15.25 mm3±3.94 mm3。2组的尖端水平偏差、角度偏差和体积损失的差异有统计学意义（P<0.05），尖端垂直偏差的差异无统计学意义（P>0.05）。结论: 在数字化导板的支持下拆除纤维桩有助于减少桩核修复后牙的体积损失，但精确度较显微镜辅助超声器械拆除低。.
Keywords: 3D printing te-chnology; cone beam computed tomography; fiber post removal; guide; microsco-pe.