Analytical model of I-bar clasps for removable partial dentures

Area of Science:

• Biomaterials Science
• Mechanical Engineering
• Dental Prosthetics

Background:

• Clasps in removable partial dentures (RPDs) are prone to fatigue stress, leading to deformation and failure.
• Computer-aided design (CAD) offers potential for optimizing RPD clasp geometry.

Purpose of the Study:

• To create an analytical model for I-bar clasps suitable for CAD-RPD applications.
• To optimize I-bar clasp design for enhanced mechanical performance and longevity.

Main Methods:

• Developed an analytical model based on mechanical principles to simulate I-bar clasp retention.
• Incorporated parameters such as vertical arm length (L1), horizontal arm length (L2), and cross-section radius (r).
• Validated the model using in vitro mechanical experiments and finite element analysis (FEA) on cobalt-chromium (Co-Cr) clasps.

Main Results:

• The analytical model demonstrated good agreement with experimental and FEA results.
• Optimal mechanical performance was achieved when L1 and L2 did not exceed 6 mm.
• Clasps with L1 > 8 mm or L2 > 9 mm exceeded the Co-Cr fatigue limit; increasing the radius conserved performance.

Conclusions:

• Co-Cr I-bar clasps are most effective on teeth with smaller mesiodistal dimensions.
• Optimized I-bar clasp design can prevent yield strength and fatigue failure.
• The developed analytical model provides a tool for designing more durable RPD clasps.