Impact of short implants numbers and prosthesis design on stress in the posterior mandible: FE analysis

Abstract

Background: This study assessed the effect of the number of short implants on stress and strain
distribution in bone in the posterior mandible using finite element analysis (FEA).
Materials and Methods: The study design utilized FEA, a computational technique. In FEA models,
short implants (4 mm diameter and 6 mm length) were placed at the site of the mandibular first
premolar to the second molar in four models: (I) two implants at the sites of teeth #4 and #7 with
two pontics at the sites of teeth #5 and #6, (II) three implants at #4, #5, and #7 with one pontic
at #6, (III) three implants at #4, #6, and #7 with one pontic at #5, and (IV) four implants at #4, #5,
#6, and #7 with no pontic. A 100 N load was applied vertically and at a 30° angle to the occlusal
surface of the crowns. Stress and strain distribution patterns in bone were evaluated using ANSYS
Workbench.
Results: The highest maximum von Mises and shear stress and strain values under vertical and
off‑axial loadings were observed in the model with two short implants at the sites of teeth #4
and #7 with two pontics at the sites of teeth #5 and #6. In general, the highest stress and strain
values were recorded following the application of off‑axial loads compared to vertical loads. In all
models, the highest stress was noted in the cervical part of the implants, while the maximum strain
occurred in the apical part of the implants.
Conclusion: Increasing the number of short implants significantly reduces stress and strain values
in peri‑implant bone.
Key Words: Dental implants, finite element analysis, strain, stress

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 Mohammad Ketabi: Pubmed,Google Scholar