Three-dimensional finite element analysis of the stress distribution on morse taper implants surface.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.