Irregular Implant Design Decreases Periimplant Stress and Strain Under Oblique Loading

Objectives To investigate whether a different implant geometry with the same potential contact surface area (PCSA) affects the principal stress and strains in bone. Material and methods Three-dimensional finite-element models were created with a single endosseous implant embedded in bone. The irregular (IR) dental root-analog implant and regular (R) cylindrical implant with the same PCSA 350 mm were modeled, keeping the size of the thinnest implant wall 0.8 mm, and the thinnest bone wall 1 mm. The regular or irregular abutments were either 4.5 mm lower than the platform of the implants or 5 mm higher than the platform of the implants, both with the taper 1.44°. A 100 N vertical or 100 N vertical/50 N horizontal occlusal loading was applied. The biomechanical behaviors of periimplant bone were recorded. Results The IR implant design experienced lower periimplant stress and strain under oblique loading than that of R implant design. In the IR implant design, comparable stress in bone, implant, and abutment were found under 100 N vertical loading or 100 N vertical/50 N horizontal loading. In the R implant design, much higher stress in bone, implant, and abutment were found under 100 N vertical/50 N horizontal loading than that under 100 N vertical loading. Conclusion Irregular dental root-analog implant is a biomechanically favorable design principle for decreasing periimplant stress and strain under oblique loading.