Dislodgement force analysis of an overdenture attachment system

Area of Science:

• Dental Implantology
• Prosthodontics
• Biomaterials Science

Background:

• The long-term performance of new overdenture attachment systems under functional stress is crucial for clinical success.
• Cyclic dislodgement testing provides valuable insights into the durability and retentive capabilities of dental attachments.

Purpose of the Study:

• To compare the dislodgement forces of a conventional (LOCATOR Legacy [LL]) and a newer (R-Tx) overdenture attachment system.
• To evaluate the effect of cyclic dislodgement on the retentive forces of these two attachment systems in various implant angulations.

Main Methods:

• Acrylic resin models with implant analogs at parallel, 30-degree, and 60-degree angulations were fabricated.
• LOCATOR Legacy (LL) and R-Tx attachments were tested for dislodgement forces before and after 1440 cycles of simulated use.
• Statistical analysis using 3-way ANOVA and Tukey HSD test determined significant differences (α=.05).

Main Results:

• A significant interaction was found between LOCATOR type, implant angle, and time (P<.001).
• Dislodgement forces differed significantly between attachment types for parallel and 60-degree divergent implants before cyclic loading.
• After cyclic loading, attachment type significantly affected forces only in parallel implants (P=.034).

Conclusions:

• Initial dislodgement forces varied by angulation and attachment type, with R-Tx higher in parallel and LL higher in 60-degree divergent implants.
• After cyclic dislodgement, forces became similar between LL and R-Tx in parallel and 60-degree divergent implants.
• Dislodgement forces generally decreased after cyclic loading, except for LL in parallel implants, and were greater with increased implant divergence.