The influence of restorative material, bone height and implant system on the stress distribution of implant-supported posterior crowns

The evaluation of the biomechanical effect of different restorative material, bone height and prosthetic connection have not been evaluated yet in the implant-supported restoration. The finite elements analysis was applied for the numerical simulation of the generated stress and the microstrain in unitary implant-supported restoration. Two implant models (13 x 3.75 mm) containing external hexagon or Morse-taper connection were simulated. Both abutments received different screw-retained crowns (acrylic resin, cobalt-chrome, metal-ceramic or all-ceramic). The substrate tissue was simulated in two levels using polyurethane resin (bone level and 5 mm bone loss). A load of 300 N was applied on the occlusal surface. Results were analyzed using von-Mises stress and microstrain criteria. Results showed that there is no difference regarding the prosthetic connection for the generated stress and strain. The different restorative materials also did not influenced the bone mechanical response. However, bone loss condition increased the stress and strain magnitude for all models. In conclusion, considering only the present model and conditions, the peri-implant tissue is not mechanically sensitive to different crown materials or prosthetic connection. Whereas, the bone loss increases the stress and strain magnitude; therefore, bone loss has a deleterious effect on the system and should be clinically controlled.