目的:探索下颌磨牙融合形牙根的根管系统构筑规律。方法:100例融合根形态的下颌磨牙采用透明法显示根管系统的空间构筑,在体视显微镜下观测并记录其形态图象。结果:融合根外形与其内的主根管分型间并无规律可循,而侧副管以管间吻合常见。结论:主根管可分为“多支型”和“直通型”两类,传统的根管分型在融合根中已不适用。 Objective: To explore the regularity of root canal system of mandibular molar fusion root. Methods: 100 cases of mandibular molars with fusion root morphology were used to show the spatial structure of root canal system. The morphological images were observed under stereomicroscope and recorded. Results: There was no regularity between the shape of the fusion root and its main root canal type, while the side tube was common to the tube. Conclusion: The main root canal can be divided into two types: “multi-branch” and “straight-through”. The traditional root canal classification is not suitable in the fusion root.