Experimental evaluation of stress distribution with narrow diameter implants: A finite element analysis

Statement of problem. Narrow diameter implants were developed to allow placement in narrow alveolar ridges. Clinicians may have concerns about the durability and function of such implants. Purpose. The purpose of this finite element study was to compare the stress values occurring on the implant and at the implant bone interface after the application of the static and dynamic forces on narrow diameter, titanium and titanium-zirconia implants in the maxillary and mandibular second premolar region. Material and methods. Titanium (Ti) and titanium-zirconium (Ti-Zr) narrow diameter implants (3.3 mm in diameter, 10 mm in length) were simulated in the maxillary and mandibular second premolar region, and metal-ceramic crown restorations were designed. Forces of 100 N were applied to crowns in a vertical and oblique (45-degree angle to the long axis) direction. Maximum and minimum principal stresses in the cortical and trabecular bone and the von Mises stresses and fatigue strength of the implants were evaluated with 3-dimensional finite element analysis. Results. In vertical and oblique static loading, Ti and Ti-Zr implants showed similar stress distribution within the same jaw models. However, the von Mises stresses in Ti-Zr implants were slightly higher than for Ti implants in all models. In oblique static and dynamic loading, all stresses were found higher than vertical loading, and fatigue failure results were found to be more critical than vertical forces. Conclusions. Based on a numerical simulation, Ti and Ti-Zr alloys can be used successfully as narrow diameter implants in the second premolar area.