Influences of Implant and Framework Materials on Stress Distribution: A Three-Dimensional Finite Element Analysis Study

Gulcan Bahadirli, DDS, PhD/Suat Yilmaz, ENG, PhD/Tobie Jones, DMD/Deniz Sen, DDS, PhD: Purpose: The aim of this study was to analyze and compare the stress distribution patterns of different implant and restorative materials in the supporting tissue and implants. Materials and Methods: Twelve different implant/bone models were created using SolidWorks 2015 software (SolidWorks Corp) and analyzed using the finite element method. Straumann Bone Level implants with zirconia abutments and single-piece Straumann PURE Ceramic implants (Institute Straumann) restored with lithium disilicate glass-ceramic and zirconia ceramic cement-retained crowns were evaluated. A 118.2-N load was applied to the coronal aspect of the buccal cusp at a 75.8-degree angle in relation to the occlusal plane. Principal stress values for cortical and trabecular bone and the equivalent von Mises stress values for implants and frameworks were calculated. Results: Zirconia (ZrO2) implant models showed lower principal stress values than the commercially pure titanium (cpTi) and titanium-zirconium (TiZr) implant models in cortical bone. All models showed similar principal stress values in trabecular bone. Von Mises stress values at the cpTi and TiZr implants were similar; however, values observed of ZrO2 implants were higher. TiZr implants of 3.3 mm diameter showed similar strength to 4.1-mm-diameter cpTi implants. Both zirconia and lithium disilicate glass-ceramic frameworks transferred similar von Mises stress values in the supporting tissue of implant-supported prostheses. Conclusion: Narrow-diameter TiZr implants may be preferred for patients who have insufficient bone volume without bone augmentation procedures due to the material’s enhanced biomechanical properties. ZrO2 implants may be a suitable alternative for esthetic regions. Further clinical studies are recommended to investigate the long-term performance of TiZr and ZrO2 implants.