Finite Element Analysis of Maxillary Overdentures Supported by Two, Three, and Four Implants

Area of Science:

• Biomaterials Science
• Dental Implantology
• Biomechanics

Background:

• Edentulous maxillas present unique challenges for dental implant rehabilitation.
• Conometric connections in implant-supported overdentures require biomechanical evaluation.
• Optimizing implant number is crucial for long-term success and stress distribution.

Purpose of the Study:

• To evaluate the biomechanical behavior of maxillary overdentures supported by 2, 3, or 4 implants with conometric connections.
• To determine the minimum number of implants required to maintain stress within physiological limits.
• To compare stress distribution under different implant configurations and cortical bone thicknesses.

Main Methods:

• Finite Element Analysis (FEA) was used to model a resorbed edentulous maxilla.
• Six models were simulated varying implant number (2, 3, 4) and cortical bone thickness (0.5 mm, 1 mm).
• Von Mises stresses in implants/abutments and principal stresses in bone were analyzed under axial loads.

Main Results:

• Two-implant models exhibited the highest deformation and stress concentrations, exceeding the 5 MPa safety threshold (6.5–8.4 MPa).
• Three- and four-implant models maintained trabecular stresses below 3 MPa and cortical bone stresses within physiological limits.
• The three-implant tripod configuration showed stress distribution comparable to four-implant models.

Conclusions:

• Overdentures supported by four implants with 1 mm cortical thickness demonstrated optimal biomechanical performance.
• A three-implant configuration is a biomechanically acceptable and potentially cost-effective alternative for maxillary overdentures.
• Further investigation into the three-implant configuration as a simplified clinical option is warranted.