A Comparison of Stability and Retention of Implant-Supported Overdenture with Ball and Locator Attachment

Statement of Problem: The location of dental implants and the retentive attachments for implant-retained overdentures are selected based on clinician preference, expert opinion, or empirical information. Limited information is available regarding implant attachment designs, and the effect on the retention and stability of mandibular implant overdentures. Aim: This investigation aims to evaluate the on the retention and stability of mandibular implant-supported overdenture with ball and locator attachment. Material and Method: An experiment was undertaken utilizing a model simulating a mandibular edentulous ridge with 4 dental implant analogs in positions approximating the tooth position in the natural dentition. 4 metal loops were attached on 4 different heat cure denture bases by acrylic resin. Metal chains were used and attached to a universal testing machine on one end and to the loops by other end, were used to measure peak load (N) required to disconnect the attachment. First part of the study evaluated retention followed by stability of 2 implant-retained over-denture based upon the ball and locator attachment design. After each of the models were subjected to 1440 pulls each to dislodge the over-denture from the acrylic model, For each group, 10 measurements were made by peak dislodging forces. Data were analyzed to determine statistical equivalence among two different attachments paired t-test and independent sample t-test (p = .05) Results:  For vertical, anterior, right and left lateral dislodging, group I recorded the highest initial and final retention, and group II recorded the lowest retention. Both the group I and group II shows gradual gradual decreases in retention and stability loss after cyclic loading. Conclusion: Ball attachment recorded the highest initial and final retention and stability (during vertical, anterior, posterior and right and left lateral dislodging) compared to locator attachment. Both the ball and locator attachment show gradual decreases in retention loss after over-denture was subjected to 1440 cyclic loading cycles