目的: 利用三维有限元分析方法分析基台边缘-牙冠的平台转移结构中粘接剂溢出的情况，旨在验证基台边缘-牙冠的平台转移结构在种植修复粘接固位中是否具有减小粘接剂流入深度的作用。方法: 利用ANSYS 19.0软件建立两个模型，一个是传统边缘及牙冠(模型一，常规组)，另一个是具有基台边缘-牙冠平台转移结构的边缘及牙冠(模型二，平台转移组)。两个模型中基台的周围均包绕着牙龈组织，边缘均位于龈下1.5 mm。利用ANSYS 19.0软件对两个模型进行双向流固耦合计算。在两个模型中，相同量的粘接剂充填于牙冠内侧壁及基台之间的间隙内，牙冠在基台上方约0.6 mm时开始进行模拟粘接的过程。牙冠匀速下落，用时为0.1 s。观察0.025 s、0.05 s、0.075 s、0.1 s时粘接剂溢出的情况，并测量0.1 s时粘接剂没过边缘的深度。结果: 在0 s、0.025 s、0.05 s时，两组模型中的粘接剂均在基台边缘以上。在0.075 s时，模型一中，牙龈被粘接剂挤压发生形变，与基台之间的间隙增加，粘接剂开始流入该间隙内；模型二中，由于牙冠颈部缩窄，粘接剂只受到来自牙龈和基台边缘向上的反作用力而向上溢出。在0.1 s时，模型一中，粘接剂由于受重力和压力的作用继续流入深处，没过基台边缘深度为1 mm；模型二中，粘接剂延续0.075 s时的状态，继续向外溢出，没过基台边缘深度为0 mm。结论: 在牙龈贴着基台的情况下，基台边缘-牙冠的平台转移结构在种植修复粘接固位中能有效减小粘接剂的流入深度。

Objective: To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention. Methods: By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s. Results: At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm. Conclusion: When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.