Backgrounds:
The aim of this study was to evaluate the stresses on the supporting bone, implants, and framework materials under masticatory forces in mandibular overdenture prostheses modeled with different framework materials and different implant types, using the finite element analysis (FEA).
Methods:
For the finite element modeling, two identical mandibular jaw models were created, one with two standard (diameter:4.1 mm/12mm length) and the other two mini-implants (diameter:2.4 mm/12mm length) placed in the canine teeth region. The PMMA denture was modeled on them, supported by Cobalt Chromium alloy (CoCr), Poly-ether ether ketone (PEEK), and Zantex materials with framework. No framework was added as a control model; only Polymethilmetacrilate (PMMA) overdenture prosthesis was modeled.
Results:
Regardless of the framework materials of the overdenture prostheses, the stress values on mini-implants in all models yielded approximately two times higher results compared to standard implants. More stress transmission was observed in the support bone and implants in PMMA prostheses and overdenture prostheses supported with PEEK, Zantex, CoCr alloy frameworks, respectively. In the framework materials, more stress occurred on CoCr, Zantex, PEEK in that order.
Conclusion:
In light of this study, the use of mini-implants as an alternative to standard implants is not promising in terms of distribution and transmission of chewing stresses. As an framework material, standard rigid metal alloys were found to be more advantageous than polymer materials in terms of stress distribution.