| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1427905 | Materials Science and Engineering: C | 2016 | 11 Pages |
•All-on-four and all-on-six concepts for the rehabilitation of maxilla were evaluated.•CoCr, Ti and Zr materials were used as framework materials.•Prototypes were successfully used to guide finite element model construction.•All-on-six approach and stiffer frameworks had favorable biomechanical behavior.•Ti framework and all-on-four concept had the most concerning results.
We evaluated two treatment concepts for the rehabilitation of moderate atrophic maxilla with dental implants (all-on-four and all-on-six) and the effect of framework material on the stress distribution of implant-support system. A three-dimensional finite element model based on a prototype was built to simulate an entirely edentulous maxilla with moderate sinus pneumatization that was rehabilitated with a full-arch fixed dental prosthesis. Four standard implants were positioned according to the all-on-four concept and four standard implants and two short implants were placed according to the all-on-six concept. Three framework materials were evaluated: cobalt-chrome (CoCr), titanium (Ti) and zirconia (Zr), totalizing six groups. A unilateral oblique force of 150 N was applied to the posterior teeth. The von Mises (σVM), maximum (σmax) and minimum (σmin) principal stress and displacements were obtained. All-on-six showed smaller σmin, σVM and σmax values on the cortical bone, implants and trabecular bone, respectively. All-on-four exhibited higher displacement levels. Ti presented the highest stress values on the cortical bone, implants, abutments, prosthetic screws and displacement levels. In conclusion, the all-on-six approach and framework stiffer materials showed the most favorable biomechanical behavior. However, the stress values did not exceed the bone resistance limits for both treatment concepts.
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