Locator retention: does variation in number and configuration matter?

Area of Science:

• Dental Implantology
• Prosthodontics
• Biomaterials

Background:

• Implant-retained mandibular overdentures offer improved stability and function.
• Understanding attachment retention is crucial for long-term overdenture success.
• Locator attachments are commonly used in overdenture applications.

Purpose of the Study:

• To evaluate the retentive strength of Locator attachments in a mandibular implant-retained overdenture model.
• To compare different implant configurations (2, 4, and 6 implants) on attachment retention.
• To assess the effect of repeated force application on retentive strength.

Main Methods:

• A clear acrylic mandibular model with 6 implant analogs and Locator abutments was used.
• A denture with 6 Locator housings was fabricated to fit the model.
• Four attachment configurations (T25, T2345, T1346, T1-6) were tested for retentive strength using 20 pulls per configuration.

Main Results:

• The 6-implant configuration (T1-6) showed the highest initial retentive strength (576.0 N).
• Configurations T1346 (354.9 N) and T2345 (350.7 N) had similar, higher retentive strengths than T25 (189.9 N).
• Retentive strength stabilized after the 7th pull for all configurations, with minimal subsequent decline.

Conclusions:

• A 6-implant configuration provides the greatest retentive strength for mandibular overdentures.
• Attachment retention is configuration-dependent, with more implants generally yielding higher strength.
• Locator attachment retention is durable, stabilizing after initial use and showing minimal loss over time.