An analytical model to design circumferential clasps for laser-sintered removable partial dentures

Area of Science:

• Biomaterials Science
• Dental Engineering
• Mechanical Engineering

Background:

• Clasps in removable partial dentures (RPDs) are prone to plastic deformation and fatigue failure, impacting prosthesis longevity.
• Laser-sintering technology enables precise fabrication of metal frameworks for dental prostheses, including complex clasp geometries.

Purpose of the Study:

• To develop a novel analytical method for designing circumferential clasps for laser-sintered RPDs.
• To prevent plastic deformation and fatigue failure in RPD clasps through optimized design.

Main Methods:

• Derived an analytical model using Euler-Bernoulli beam theory and Castigliano's energy method.
• Validated the model with Finite Element Analysis (FEA) and pull-out experiments on laser-sintered cobalt-chromium (Co-Cr) prostheses.

Main Results:

• The analytical model showed good agreement with FEA and experimental data.
• Identified optimal design parameters for Co-Cr molar clasps (13mm length, 1.2mm cross-section radius for 0.25mm undercut) to achieve 10N retention without failure.
• Highlighted that shorter clasps for premolars experience high stresses, leading to potential deformation and fatigue failure.

Conclusions:

• Laser-sintered Co-Cr circumferential clasps are safe for molar applications when designed according to the proposed model.
• Circumferential clasps in premolars require further investigation due to inherent susceptibility to failure.