上颌前磨牙全瓷嵌体修复三维有限元模型的建立与应力分析

目的建立上颌前磨牙Ⅱ类洞全瓷嵌体修复的计算机三维实体模型和有限元模型,并进行应力分析,以期为临床全瓷嵌体修复提供理论参考。方法利用Micro-CT扫描获得牙体原始数据,建立上颌前磨牙Ⅱ类洞全瓷嵌体修复的三维有限元模型,采用有限元分析软件ANSYS10.0计算分析牙釉质、牙本质、嵌体及粘结剂层的最大主应力。结果建立了包含牙釉质、牙本质、牙髓腔、牙周膜、嵌体及粘结剂层的上颌前磨牙Ⅱ类洞嵌体修复的精细三维有限元模型。牙釉质的应力集中部位在洞型龈壁的位置,最大主应力值为10.52MPa;牙本质的应力集中部位在牙本质近牙髓腔的位置,最大主应力值为3.76 MPa;嵌体的应力集中部位在其与龈壁对应的位置及嵌体底面,最大主应力值为5.82 MPa。结论上颌前磨牙Ⅱ类洞全瓷嵌体修复后,牙釉质的薄弱部位在龈壁;牙本质的薄弱部位在窝洞底部近牙髓腔的位置;嵌体的薄弱部位在其与龈壁对应的位置。

Establishment of 3D finite element model of maxillary premolar restored with ceramic inlay and primary analysis of stress distribution

Objective To establish a 3D solid and finite element model of maxillary premolar with classⅡ cavity restored by ceramic inlay and analyze the stress distribution.Methods The first permanent maxillary premolar was scanned by Micro-CT and a three-dimensional finite element model with class Ⅱ cavity restored by ceramic inlay estblished.The stress distribution and the level of stress concentration in the restoration,tooth structure and resin cement were analyzed by the FEA software.Results A more precise 3D solid and finite element model of maxillary premolar with classⅡcavity restored by ceramic inlay was constructed,which included enamel,dentin,pulp chamber and peridentium.The tensile stress concentrated in the gingival wall in enamel,and near the gingival wall of tooth in inlay,and on the inner surface of dentin near the pulp in dentin.Conclusion The gingival wall of tooth and the inner surface of dentin near the pulp were the unsubstantial area of maxillary premolar with class Ⅱ cavity restored by ceramic inlay.