Ou M E, Ding Y, Tang W F, Zhou Y S
Third Clinical Division, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology, Beijing 100083, China.
Department of Prosthodontics, Peking University School and Hospital of Stomatology, Bejing 100081, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2023 Jun 18;55(3):548-552. doi: 10.19723/j.issn.1671-167X.2023.03.023.
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.
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.
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.
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.
采用三维有限元分析方法分析基台边缘 - 冠平台转换结构中的骨水泥流动情况，以验证基台边缘 - 冠平台转换结构在种植体粘结固位中是否能减少骨水泥的流入深度。
使用ANSYS 19.0软件建立两个模型，一个是边缘和冠部常规的模型（模型一，传统组），另一个是具有基台边缘 - 冠平台转换结构的模型（模型二，平台转换组）。两个模型的基台均被牙龈包裹，基台边缘位于黏膜下1.5mm处。使用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，在冠部内侧和基台之间放置等量的骨水泥。当冠部高于基台0.6mm时，模拟冠部与基台粘结的过程。冠部在整个过程中以恒定速度下降，耗时0.1s。然后在0.025s、0.05s、0.075s、0.1s时观察冠部外侧的骨水泥流动情况，并在0.1s时测量边缘上方骨水泥的深度。
在0s、0.025s、0.05s时，两个模型中的骨水泥均在基台边缘上方。在0.075s时，在模型一中，骨水泥挤压牙龈使其变形，然后在牙龈与基台之间形成间隙，骨水泥开始流入该间隙。在模型二中，由于冠部颈部狭窄，骨水泥受到牙龈和基台边缘向上的反作用力挤压，从牙龈处流出。在0.1s时，在模型一中，骨水泥在重力和压力作用下继续向深部流动，边缘上方骨水泥的深度为1mm。在模型二中，在0.075s时骨水泥继续从牙龈处流出，边缘上方骨水泥的深度为0mm。
当基台被牙龈包裹时，基台边缘 - 冠平台转换结构在种植体粘结固位中可减少骨水泥的流入深度。
