All-on-4 concept: a 3-dimensional finite element analysis.

Area of Science:

• Biomaterials Engineering
• Dental Implantology
• Biomechanics

Background:

• All-on-4 implant-supported prostheses offer a solution for edentulous patients.
• Understanding the biomechanical behavior of these prostheses is crucial for long-term success.
• Distal implant angulation is a key factor influencing stress distribution.

Purpose of the Study:

• To investigate the biomechanical behavior of All-on-4 implant-supported prostheses.
• To compare stress distribution with varying distal implant tilt degrees (15°, 30°, 45°).
• To identify critical tilt angles affecting peri-implant bone stress.

Main Methods:

• Finite element analysis (FEA) of 3D models of edentulous maxilla with All-on-4 prostheses.
• Simulation of 4 distinct loading conditions.
• Quantification and comparison of von Mises stresses around implants for each tilt configuration.

Main Results:

• Negligible stress differences between 15° and 30° distal implant tilt angles.
• The 45° tilt angle demonstrated the highest stress concentration at the peri-implant bone.
• Maximum stresses were consistently observed at the neck of distal implants, increasing with tilt angle.

Conclusions:

• Increasing distal implant tilt angle in All-on-4 prostheses proportionally increases stress concentration.
• The 45° tilt configuration poses the highest risk for peri-implant bone, particularly at the bone-implant interface.
• Optimal distal implant angulation is critical for minimizing stress and ensuring prosthesis longevity.