Toniollo Marcelo Bighetti, Macedo Ana Paula, Rodrigues Renata Cristina Silveira, Ribeiro Ricardo Faria, Mattos Maria da Glória Chiarello de
Dental School of Ribeirão Preto, University of São Paulo, Department of Dental Materials and Prosthodontics, Avenida do Café, sn, Monte Alegre, Ribeirão Preto, SP 14040-904, Brazil.
J Prosthodont Res. 2013 Jul;57(3):206-12. doi: 10.1016/j.jpor.2013.02.003. Epub 2013 Jun 15.
This finite element analysis (FEA) compared stress distribution on external surface of different morse taper implants, varying implant bodies length and dimensions of metal-ceramic crowns in order to maintain the occlusal alignment.
Three-dimensional finite element (FE) models were designed representing a posterior left side segment of the mandible: group 0, 3 implants of 11 mm length; group 1, implants of 13 mm, 11 mm and 5mm length; group 2, 1 implant of 11 mm and 2 implants of 5mm length; group 3, 3 implants of 5mm length. The abutments heights were 3.5mm for 13 mm and 11 mm implants (regular) and 0.8mm for 5mm implants (short). Evaluation was performed on a computer program (Ansys software), with oblique loads of 365N for molars and 200 N for premolars, applied on ridges of cusps and grooves.
Abutments with 0.8mm height generated less von Mises stresses compared with 3.5mm height. The use of short implants associated with bigger crowns concentrated higher stress distribution and stress values on the surface implants, principally on the vestibular side (oblique direction of the loads). The more distal implant concentrated higher stress.
Moreover, these 5mm implants were positioned at the cortical bone level, which has higher elastic modulus and may have influenced at the stress distribution. However, despite the higher stresses, these implants were well able to withstand the applied forces.
本有限元分析（FEA）比较了不同莫氏锥度种植体的外表面应力分布，改变种植体长度以及金属烤瓷冠的尺寸，以维持咬合对齐。
设计三维有限元（FE）模型，代表下颌骨左侧后段：0组，3颗长度为11mm的种植体；1组，长度分别为13mm、11mm和5mm的种植体；2组，1颗长度为11mm的种植体和2颗长度为5mm的种植体；3组，3颗长度为5mm的种植体。对于13mm和11mm的种植体（常规），基台高度为3.5mm；对于5mm的种植体（短种植体），基台高度为0.8mm。在计算机程序（Ansys软件）上进行评估，对磨牙施加365N的斜向载荷，对前磨牙施加200N的斜向载荷，施加于牙尖和沟嵴处。
与3.5mm高度的基台相比，0.8mm高度的基台产生的冯·米塞斯应力更小。使用短种植体并搭配较大的牙冠会使种植体表面的应力分布和应力值更高，主要集中在前庭侧（载荷的斜向方向）。越靠后的种植体应力集中越高。
此外，这些5mm的种植体位于皮质骨水平，皮质骨具有较高的弹性模量，可能影响了应力分布。然而，尽管应力较高，这些种植体仍能够很好地承受所施加的力。
