Results: The fracture occurred vertically, and mostly on the 1/3 of the tip of roots and 1/3 of the middle of the roots in the metal post and titian post group.

• 结果：不锈钢螺纹桩组和钛桩组离体牙折裂多发生在根尖1/3处和根中1/3处，为垂直向折裂；