Holmgren E P, Seckinger R J, Kilgren L M, Mante F
University of Pennsylvania School of Dental Medicine, Philadelphia, USA.
J Oral Implantol. 1998;24(2):80-8. doi: 10.1563/1548-1336(1998)024<0080:EPOODI>2.3.CO;2.
Finite element analysis (FEA) has been proven to be a precise and applicable method for evaluating dental implant systems. By means of FEA, a parasaggital model was digitized from a computed tomography (CT)-generated patient data set, and various single-tooth, osseointegrated, two-dimensional dental implant models were simulated. The specific aims of the study were to: (1) examine the effect of implant diameter variation (3.8 mm-6.5 mm) of both a press-fit, stepped cylindrical implant type and a press-fit, straight cylindrical implant type as osseointegrated in the posterior mandible; (2) compare the stress-dissipating characteristics of the stepped implant versus the straight implant design; and (3) analyze the significance of bite force direction (vertical, horizontal, and oblique 45 degrees) on both implant types. The results of the FEA suggested that (1) using the widest diameter implant is not necessarily the best choice when considering stress distribution to surrounding bone, but within certain morphological limits, for both implant types, an optimum dental implant exists for decreasing the stress magnitudes at the bone-implant interface; (2) stress is more evenly dissipated throughout the stepped cylindrical implant when compared to the straight implant type; and (3) it is important in FEA of dental implants to consider not only axial forces (vertical loading) and horizontal forces (moment-causing loads), but also to consider a combined load (oblique bite force), since these are more realistic bite directions and for a given force will cause the highest localized stress in cortical bone. The theoretical analysis performed implies that clinically, whenever possible, an optimum, not necessarily larger, dental implant should be used based on the specific morphological limitations of the mandible and that a stepped cylindrical design for press-fit situations is most desirable from the standpoint of stress distribution to surrounding bone.
有限元分析（FEA）已被证明是评估牙种植系统的一种精确且适用的方法。通过有限元分析，从计算机断层扫描（CT）生成的患者数据集中将一个矢状旁模型数字化，并模拟了各种单牙、骨结合的二维牙种植体模型。该研究的具体目的是：（1）检查在后下颌骨中骨结合的两种压配式阶梯圆柱形种植体类型和压配式直圆柱形种植体类型的种植体直径变化（3.8毫米至6.5毫米）的影响；（2）比较阶梯形种植体与直形种植体设计的应力消散特性；（3）分析咬合力方向（垂直、水平和45度斜向）对两种种植体类型的意义。有限元分析结果表明：（1）在考虑对周围骨的应力分布时，使用最宽直径的种植体不一定是最佳选择，但在一定形态学限制内，对于两种种植体类型，都存在一种最佳牙种植体，可降低骨-种植体界面处的应力大小；（2）与直形种植体类型相比，应力在阶梯圆柱形种植体中更均匀地消散；（3）在牙种植体的有限元分析中，不仅要考虑轴向力（垂直加载）和水平力（引起力矩的载荷），还要考虑组合载荷（斜向咬合力），这一点很重要，因为这些是更现实的咬合力方向，并且对于给定的力，会在皮质骨中引起最高的局部应力。所进行的理论分析表明，在临床上，只要有可能，应根据下颌骨的特定形态学限制使用最佳的、不一定更大的牙种植体，并且从对周围骨的应力分布角度来看，压配情况下的阶梯圆柱形设计是最理想的。
