Effect of geometry on clasp retention force: a finite element analysis study

Area of Science:

• Dental prosthetics
• Biomaterials engineering
• Computational mechanics

Background:

• Clasp retention force is critical for denture stability but is affected by complex geometric factors.
• Understanding the fundamental relationship between clasp geometry and retention force is challenging with realistic designs.
• Simplified geometric models are essential for isolating and analyzing key design parameters.

Purpose of the Study:

• To investigate the relationship between clasp geometry and retention force using finite element analysis (FEA).
• To establish quantitative correlations between specific geometric parameters and the resulting retention force.
• To provide a foundation for optimizing clasp design for improved retention and stability.

Main Methods:

• Developed 3D finite element models of rod-shaped and bending clasps using ANSYS 19.0.
• Analyzed rod models with varying lengths (1-15 mm) and diameters (0.6-1.6 mm).
• Analyzed bending models with varying base widths (6-12 mm) and heights (0.5-5 mm), all from cobalt-chromium alloy.

Main Results:

• Maximum stress consistently localized at the clasp base for all models.
• For rod clasps, retention force showed a third-power decrease with length and a fourth-power increase with diameter.
• For bending clasps, retention force was inversely proportional to the cube of base width and the first power of height.

Conclusions:

• FEA successfully elucidated distinct, quantifiable relationships between clasp geometry and retention force.
• The findings provide a basis for predicting retention force based on key geometric dimensions.
• Further laboratory validation is recommended to confirm these computational findings.