Objective: to evaluate the retention and wear of the ball and socket and locator attachments for implant retained overdenture.

Subjects and Methods: Four dental implants (diameter, 3.8 mm; length, 12 mm) were imbedded into the prepared beds of two polyethylene blocks. Twenty acrylic prosthetic components were fabricated and connected to the ball and locator abutments. Tensile force was applied to the prosthetic components until the attachments were separated from the abutments. All samples were subjected to 5,000 insertion-separation cycles. Retention forces were measured after 10, 100, 200, 300, 400, 500, 1,000, 1,500, 2,000, 3,000, 4,000, and 5,000 insertion-separation cycles. Additionally, the wear of the attachments was measured using scanning electron microscopy. Data were analyzed to determine statistical equivalence among the two different attachments using the Student t test procedure .

Results: :locator attachments showed significant retention loss after 10, 100, 200, 300, 400, 500, 1,000, 1,500, 2,000, 3,000, 4,000, and 5,000 insertion-separation cycles (P < .05). Retention loss after 5,000 cycles was detected significantly more often for locator attachments (p=0.0009) than for ball and socket attachments (P = 0.0009). No significant difference was detected between the wear on the two attachment systems after 5,000 cycles (P > .05).

Conclusion: Both attachment systems showed decreased retentive forces after 5,000 insertion-separation cycles. However, after 5,000 insertion-separation cycles, ball and socket attachments showed better retentive properties than locator attachments. Both attachment systems showed wear patterns after 5,000 insertion-separation cycles, but this wear greater with locator attachment more than ball and socket abutment..