الفهرس 
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Abstract
The current study tries to determine the best bar material for two implantsupported mandibular overdenture. A digital model simulating edentulous mandible was constructed from a laser scanned dry human mandibule. The model was modified by Solidworks software to obtain structured mandible (spongy bone and mucosa, implants, bar and denture). The model was duplicated into 2 identical models except for the bar material .
•Model I.cobalt-chromium bar.
• Model II. zirconium bar.
The properties of materials, elements and structures were entered into the program.
Two types of loads were applied to the overdenture in each model to simulate functional loading, vertical and inclined distributed loads on the first premolar, second premolar and first molar.
Stresses were measured using finite element program (Solidworks software) and the differences in stress distribution were collected.
The results revealed that:
•Stresses in model I ranged from 0.508 Mpa in mucosa in the loaded side under vertical loading to 388.146 Mpa in the implant under vertical loading and from 0.536 Mpa in mucosa in the loaded side under oblique loading to 247.667 Mpa in the implant under oblique loading.
•Stresses in model II ranged from 0.508 Mpa in mucosa in the loaded side under vertical loading to 386.603 Mpa in the implant under vertical loading and from 0.535 Mpa in mucosa in the loaded side under oblique loading to 243.018 Mpa in the implant under oblique loading.