偏颌患者虚拟排牙的根骨关系研究

Study on root-bone relationship of diagnostic models in patients with facial asymmetry

目的 通过对比采用传统牙冠模型与根骨数字化的三维整合模型进行虚拟排牙的牙根位置,探讨根骨信息在虚拟排牙中的重要性。方法 选择骨性偏颌患者11例。获取治疗前口内扫描牙冠数据,即治疗前传统牙颌模型,将CBCT根骨信息与传统牙颌模型配准、整合得到治疗前三维整合模型。由专业排牙技师1名分别采用传统牙颌模型与三维整合模型进行虚拟排牙,得到P1、P2目标位。同时,将根骨信息与P1、P2目标位整合,得到P1与P2的三维整合模型。比较P1、P2的移动设计、牙根外露与牙根平行度差异。结果 P1存在明显的牙根外露与牙根不平行,而P2可显著改善。P2相对P1移动变化集中于偏斜侧牙齿、部分非偏斜侧后牙的颊舌向整体移动、转矩,部分前牙的近远中整体移动。结论 包含根骨信息的隐形矫治设计系统可以帮助优化目标位,改善骨开窗、骨开裂、牙根平行度欠佳等问题。

Objective To investigate the importance of root-bone information through comparison of root position in diagnostic model set up with the traditional crown models and the composite tooth models. Methods Traditional digital models obtained by intraoral scanner were collected from 11 patients with facial asymmetry. The CBCT-based model and traditional digital model were registered and integrated to create a pretreatment composite tooth models. The P1 and P2 diagnostic model setup were respectively performed on the traditional digital model and composite tooth model by a professional i-align technician. CBCT-based model was put into P1 and P2 virtual setup to obtain composite tooth models. Mobility design, root exposure and root parallelism were compared between P1 and P2 composite tooth models. Results Nonparallel and exposure of the roots were found in P1 composite tooth model. In P2, the nonparallel and exposure of the root have been improved. By comparison, the mobility design difference of P2 were mainly the buccolingual movement and torque of deviated teeth and some non-deviated posterior teeth, as well as the mesiodistal movement of some anterior teeth. Conclusion Invisalign design system containing root-bone information can help optimize diagnostic model and improve fenestration, dehiscence and root parallelism.