下颌第一恒磨牙根尖形态的显微CT研究

目的:使用显微CT研究下颌第一恒磨牙根尖5 mm形态。方法:采用显微CT对152颗离体下颌第一恒磨牙进行扫描,利用3-D软件三维重建根尖5 mm形态。记录根尖孔和侧副孔数目、峡区发生和分型。结果:94.08%下颌第一恒磨牙有两个单独牙根,61.84%有3个根管。60.91%的近中根有两个根尖孔。37.27%的近中根和33.01%的远中根有侧副孔。73.68%的牙出现峡区,峡区形态以IV型最为常见。结论:下颌第一磨牙根尖形态复杂,常规根管治疗和根尖手术应考虑其复杂性。

Investigation on Apical Morphology of Mandibular First Molar Using Micro-computed Tomography

Objective: To investigate the apical morphology of the mandibular first molar in Chinese population using micro-computed tomographic technique. Methods: A total of 152 mandibular first molars were scanned by micro-competed tomography with the resolution of 30 μm. The 3-dimensional (3D) images of all specimens in apical 5mm of the roots were reconstructed. The numbers of roots and root canal, the numbers of apical foramina and lateral/accessory foramina, the prevalence and types of isthmus were recorded. Results: The incidence of two separated roots of the first molars was 94.08%. The incidence of three separated roots was 61.84%. The percentage of two apical foramina in the mesial roots was 60.91%. The percentage of lateral/accessory foramina was 37.27% in the mesial roots and was 33.01% in the distal roots. The incidence of root canal isthmus was 73.68%. Type IV in isthmuses was the most common configurations. Conclusion: The apical canal configuration of mandibular first molars was complicated and should be taken into account during nonsurgical and surgical endodontic procedures.