Biomechanical Comparison of Asymmetric Implant Configurations for All-on-Four Treatment Using Three-Dimensional...

Area of Science:

• Dental Implantology
• Biomaterials Engineering
• Biomechanics

Background:

• The all-on-four concept utilizes strategically placed implants to support full-arch prostheses.
• Understanding stress distribution is crucial for long-term implant success and preventing bone resorption.

Purpose of the Study:

• To analyze the impact of unilaterally more posterior implant placement on stress distribution in bone and prosthetic components within the all-on-four concept.
• To compare stress patterns under vertical and oblique forces across different implant positioning models.

Main Methods:

• Finite element analysis (FEA) was employed to model three distinct implant placement scenarios (M1, M2, M3).
• Straumann BLT implants (4.1 mm diameter, 12 mm length) were simulated.
• Vertical and oblique forces of 100 N were applied, and von Mises and principal stresses were calculated.

Main Results:

• Oblique forces resulted in the highest stress concentration on cortical bone, particularly in the second premolar region.
• Model 1 (M1) showed the highest bone stress (8.992 MPa), followed by Model 3 (M3) and Model 2 (M2).
• Model 2 (M2) exhibited the highest stress on prosthetic components (621.43 MPa) under oblique forces, followed by M3 and M1.

Conclusions:

• Placing implants further posterior, potentially to the first molar region, might mitigate crestal bone resorption due to high stress.
• However, increased posterior placement may elevate stress on implants and prosthetic parts, raising concerns about potential failures.
• Optimizing implant positioning is essential to balance bone preservation and prosthetic component integrity.