Load transfer by a maxillary distal-extension removable partial denture with cap and ring extracoronal attachments

Area of Science:

• Biomaterials Science
• Dental Prosthetics
• Biomechanics

Background:

• Removable partial dentures (RPDs) are crucial for restoring function and aesthetics.
• Extracoronal attachments (ERAs) offer aesthetic advantages over conventional clasps.
• Understanding stress distribution is vital for RPD longevity and patient comfort.

Purpose of the Study:

• To photoelastically compare stress distribution in maxillary RPDs with different ERA attachment retentions (light vs. heavy).
• To evaluate the influence of supporting rests and abutment splinting on stress distribution.
• To compare the stress distribution of ERA attachment RPDs with previously studied I-bar designs.

Main Methods:

• Photoelastic stress analysis was employed to compare stress patterns.
• Maxillary bilateral distal-extension RPDs with ERA attachments were fabricated.
• Prostheses were tested with and without supporting rests and with and without abutment splinting.

Main Results:

• Light retention ERA attachments, supporting rests, and abutment splinting yielded the most favorable stress distributions.
• This optimal configuration demonstrated comparable stress distribution to maxillary I-bar retained RPDs from prior research.
• Heavy retention attachments and lack of rests or splinting resulted in less favorable stress patterns.

Conclusions:

• Light retention ERA attachments, combined with supporting rests and abutment splinting, optimize stress distribution in distal-extension RPDs.
• This configuration represents an effective design for maxillary removable partial dentures.
• ERA attachments can provide favorable biomechanical performance comparable to other RPD designs when optimally configured.