Effect of crown to implant ratio and implant dimensions on periimplant stress of splinted implant-supported crowns: a finite element analysis.

Purpose: To assess the influence of different crown-implant (C/I) ratios and implant dimensions on periimplant stress in the partially edentulous posterior mandible by 3-dimensional finite element analysis (FEA).
Materials and Methods: Two implants were placed in the second premolar and first molar regions of the mandibular model. The implants were then splinted with a 2-unit fixed bridge. The influence of 3 parameters (C/I ratio, implant length, and implant diameter) on periimplant bone stress was then analyzed by using FEA.
Results: C/I ratios showed a direct relationship with periimplant bone stress, but the absolute height of the clinical crown had a much more significant influence. The implant length had less influence on the periimplant bone stress than the implant diameter. Lower stress values were detected in wide-diameter implants, even in scenarios involving long crowns.
Conclusions: Crown height is a more important factor affecting the periimplant bone stress than the C/I ratio for splinted implant-supported crowns. Two-unit fixed restorations with high C/I ratios may be successfully used with wide-diameter implants in the posterior mandible.