Objective: To evaluate the influence of different tilting angles of the mandibular third molar on the stress distribution in the restoration, odontal tissue and periodontal membrane as bridge abutments after the restoration of fixed partial denture. Methods: Based on a 3-D finite element model of three abutments of the rigid fixed bridge in deletion of first molar and second molar in mandibular, evaluate the influence of the mandibular third molar with different tilting angles of 0°, 10°, 20°, 30° and 40° on the stress distribution in the restoration, odontal tissue and periodontal membrane by a software named Ansys. Results: When the tilting angle of third molar was increasing, the max Von Mises stresses of the restoration, odontal tissue and periodontal membrane were increasing. When third molar tilted at 30°, the Von Mises stress peak value (9.1 IMPa) on the peridental membrane of third molar was 2.4 times than the normal third molar(3.81MPa). Conclusions: The tooth tilted more than 30° could not be selected as an abutment in the restoration of fixed partial denture, and the clinicians should lower the height of the cusp to reduce the oblique load of the abutment when fixed bridge was used as a treatment%目的:下颌第一二磨牙缺失三基牙双端固定桥修复的条件下,分析近中倾斜不同角度的第三磨牙作为基牙后受力时修复体、牙体组织及牙周膜的应力分布情况,为临床修复提供理论依据.方法:在已建好的第一二磨牙缺失三基牙双端固定桥修复的三维有限元模型基础上,将第三磨牙近中倾斜0°、10°、20°、30°和40°,通过Ansys软件分析修复体、牙体以及牙周膜的应力变化情况.结果:无论是垂直加载还是倾斜加载,修复体的等效应力最大值位于第二三磨牙之间的连接体处;随着第三磨牙倾斜角度的增加,修复体、牙体以及牙周膜的等效应力极值增加.当第三磨牙倾斜30°时,垂直载荷下,第三磨牙牙周膜等效应力极值(9.11MPa)约为无倾斜时(3.81MPa)的2.4倍.结论:当牙齿倾斜角度大于30°时,不适宜作为固定桥的基牙,并且行固定桥修复时,应适当降低牙尖斜度,减小基牙的侧向力.
展开▼
