Abstract
The retention for overdenture attachments depends on design, location, alignment of supporting dental implants and the type of attachments. The goal of this in vitro study was to evaluate and measure retention between PEEK and ZIRCON milled bar materials in implant-supported over-denture prosthesis. An overdenture with titanium framework was made on an edentulous mandibular model with 4 OXY implants Piesse line (3.5 X 11.5mm) in the canine and premolar area connected with two different bar materials. The overdenture attachments were subjected to 5 consecutive pulls on a universal testing machine with a crosshead speed of 50 mm/min in the vertical directions. The over denture was inserted and removed 3240 times in a vertical direction perpendicular to occlusal plane to simulate prosthesis wearing about 3 years. Another five pulls were made and the mean used to represent final retention values. Analysis of Two-way ANOVA were used to determine differences between mean retention values (α = .05) The highest average value retention was recorded for the PEEK bar with in  the vertical direction.