Pratheep K V, Abraham Abby, Annapoorni H, Vigneshwaran S
Department of Prosthodontics and Crown and Bridge, Meenakshi Ammal Dental College and Hospital, Meenakshi Academy of Higher Education and Research University, Chennai, Tamil Nadu, India.
Indian J Dent Res. 2013 Jul-Aug;24(4):439-45. doi: 10.4103/0970-9290.118388.
This study aims at evaluating stresses generated in a fixed tooth to implant connected fixed partial denture (FPD) by finite element method by varying implant design and position, in unilateral distal extension cases, i.e. for replacing mandibular 1 st and 2 nd molars.
Four models were created, Model 1-A finite element model (FEA) model of a crestal implant-tooth connected metal ceramic FPD with pontic in 36 region. The 35 region simulated the second premolar. Model 2-A FEA model of a basal implant-tooth connected metal ceramic FPD. Model 3-A FEA model of a crestal implant in 36 region connected to tooth 35 and cantilevered posteriorly with pontic in 37 region, made of metal ceramic. Model 4-A FEA model of a basal implant in 36 region connected to tooth 35 and cantilevered posteriorly with pontic in 37 region, made of metal ceramic. A vertical force of 100N directed evenly on the nodes on the occlusal surface of each of the three crowns. The models displayed stress both numerically and by color coding.
On comparing models 1 and 2, the model 1 showed comparatively more stresses in crestal bone area of the implant. On comparing models 3 and 4, model 3 showed lesser von misses stress values.
In case of tooth implant connected FPDs without any cantilevers, basal implants show better stress distribution when compared to crestal implants. In case of cantilever designs, crestal implant design showed lower stress values, but the difference in stresses were less.
本研究旨在通过有限元方法，在单侧远中游离端病例中，即替换下颌第一和第二磨牙时，通过改变种植体设计和位置，评估固定牙-种植体连接固定局部义齿（FPD）中产生的应力。
创建了四个模型，模型1——种植体位于牙槽嵴顶、与牙齿相连的金属烤瓷FPD的有限元模型（FEA），桥体位于36区。35区模拟第二前磨牙。模型2——种植体位于根尖、与牙齿相连的金属烤瓷FPD的FEA模型。模型3——36区牙槽嵴顶种植体与35牙相连、桥体位于37区并向后悬臂的金属烤瓷FEA模型。模型4——36区根尖种植体与35牙相连、桥体位于37区并向后悬臂的金属烤瓷FEA模型。在三个牙冠的咬合面上，将100N的垂直力均匀施加在节点上。模型以数值和颜色编码显示应力。
比较模型1和2时，模型1在种植体牙槽嵴顶骨区域显示出相对更多的应力。比较模型3和4时，模型3显示出较小的冯·米塞斯应力值。
在无悬臂的牙种植体连接FPD中，与牙槽嵴顶种植体相比，根尖种植体显示出更好的应力分布。在悬臂设计中，牙槽嵴顶种植体设计显示出较低的应力值，但应力差异较小。
