Effect of abutment angulation in the retention and durability of three overdenture attachment systems: An in vitro study

PURPOSE: This in vitro study investigated and compared the durability and retention of three types of attachments. MATERIALS AND METHODS: Three commercially available attachments were investigated: Clix®, Dalbo-Plus® and Locator®. In total, 72 samples of these attachments were placed in the acrylic resin forms and subjected to mechanical testing (5400 cycles of insertion and removal) over the respective ball or Locator abutments immersed in artificial saliva at pH 7 and 37℃. The abutments were placed at angulations of 0°, 10° and 20°. The retention force was recorded at the beginning and after 540, 1080, 2160, 3240, 4320 and 5400 insertion-removal cycles. RESULTS: The results revealed that there were significant differences in the average values of the insertion/removal force due to angulation (F ((2.48)) = 343619, P<.05) and the type of attachment (F ((7.48)) = 23.220, P<.05). CONCLUSION: Greater angulation of the abutments was found to influence the retention capacity of the attachments, and the fatigue test simulating 5 years of denture insertion and removal did not produce wear in the metal abutments.