Retentive force variations of stud attachments for implant overdentures

Area of Science:

• Dental Implantology
• Prosthodontics
• Biomaterials Science

Background:

• Implant overdentures are a common solution for edentulous mandibles.
• Stud attachments, including O-ring/ball and Locator systems, are frequently used in overdenture construction.
• Understanding attachment retentive forces is crucial for long-term clinical success.

Purpose of the Study:

• To compare the retentive forces of O-ring/ball and Locator overdenture attachments.
• To evaluate attachment performance under simulated dry and wet oral conditions.
• To assess the impact of insertion-removal cycles on retentive properties.

Main Methods:

• Pull-out tests were conducted on O-ring/ball and Locator attachments.
• Testing simulated dry conditions and wet conditions using a saliva substitute.
• Retentive forces were measured after various numbers of insertion-removal cycles.

Main Results:

• In dry conditions, O-ring/ball attachments initially showed higher retention but significantly decreased after 50 cycles.
• Locator attachments demonstrated stable retentive forces in dry conditions over time.
• Wet conditions increased the retentive force of O-ring/ball attachments; Locator attachments showed increased retention after 510 cycles.

Conclusions:

• O-ring/ball attachments are not recommended for implant overdentures in dry mouth environments due to significant retentive force loss.
• Locator attachments or metal-to-metal components are preferable for implant overdentures in dry conditions.
• In saliva-irrigated mouths, both O-ring/ball and Locator attachments exhibit comparable retentive properties over 6-9 months.