Deflections in Mandibular Major Connectors: A FEM Study

Area of Science:

• Biomaterials Science
• Dental Prosthetics
• Mechanical Engineering

Background:

• Major connectors are crucial in removable partial dentures, requiring rigidity to withstand occlusal forces and prevent damage to abutment teeth.
• Lingual bars and lingual plates are common mandibular major connectors, each with distinct biomechanical properties.
• Understanding connector deflection is vital for optimizing denture design and patient outcomes.

Purpose of the Study:

• To assess and compare the deflection of different mandibular major connector designs under occlusal load using finite element analysis.
• To evaluate the biomechanical performance of lingual bars versus lingual plates across various Kennedy classifications (I-IV).

Main Methods:

• Finite element analysis (FEA) was employed to model and analyze six framework designs with lingual bars and lingual plates for Kennedy's Class I-IV situations.
• Three-dimensional models of human edentulous mandibles were created from CT scans.
• A vertical biting force of 20N was applied to simulate occlusal loading.

Main Results:

• Maximum deflection occurred in the saddle area, followed by the major connector and occlusal rest regions.
• Lingual plates demonstrated greater rigidity (less deflection) compared to lingual bars.
• In Kennedy's Class III situations, lingual bars showed the least deflection, while in Class IV, lingual plates exhibited the least deflection.

Conclusions:

• Lingual plates are generally more rigid than lingual bars, offering superior resistance to deformation.
• The choice of major connector design should consider the specific Kennedy classification to minimize deflection and ensure functional stability.
• FEA is a valuable tool for evaluating the biomechanical behavior of dental prostheses components.