Evaluation of stress distribution of porous tantalum and solid titanium implant‑assisted overdenture in the mandible: A finite element study

Abstract

Background: The present study aimed to evaluate the stress distribution of porous tantalum
implant and titanium solid implant assisted overdenture (IAO) in mandibular bone by utilizing
three‑dimensional (3D) finite element (FE) analysis.
Materials and Methods: In this FE study, an existing cone‑beam volumetric tomography scan of
a patient without any maxillofacial anomaly with an available acceptable IAO for mandible was used
to attain the compartments of a completely edentulous mandible. Zimmer trabecular implants and
locator attachment systems were selected as the case group (Model B), and Zimmer Screw‑Vent
implants and locator attachment system were chosen for the control (Model A), as overdenture
attachments in the present study. The mandibular overdenture was scanned and digitized as a FE
model. Two 3D FE models were designed as edentulous lower jaws, each with four implants in the
anterior section of the mandible. Three forms of loads were directed to the IAO in each model:
Vertical loads on the left first molar vertical molar (VM). Vertical loads on the lower incisors (VI).
Inclined force buccolingually applied at left first molar (IM).
Results: Under all loading conditions, the maximum strain values in peri‑implant bone in Model
A were less than Model B. Under VI, the greatest stress value around abutments in both models
was about 2–3 times higher than the other loads. Under VM and IM loads, no significant difference
was observed between models.
Conclusion: Using trabecular metal implants instead of solid implants reduces strain values around
both cortical and trabecular bone.
Key Words: Dental implants, overdenture, porous, tantalum