الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This in vitro examine changed into conducted to evaluate and compare retention forces of maxillary overdenture retained by two special milled bars (metallic versus zirconia) for 2160 cycle of insertion and removal (simulation of years of usage).
One trendy acrylic version representing absolutely edentulous maxillary arch was used. Four identical internal hex implants (13mm length &3.5mm diameter) had been inserted within the dog and 2d premolar areas perpendicular to the residual ridge vicinity bilaterally. In this wellknown acrylic model same overdentures have been fabricated after titanium and zirconia bars had been milled with aid of CAD CAM. The axial (significant) retention values of every bar with its overdenture had been envisioned and as compared the usage of a common testing machine.
The metallic part of the denture base had a u-fashioned occlusal plate with a metallic ring for the attachment of the trying out device. The generic trying out gadget turned into used to test the retention of the two milled bars at the zero level (T0) and after 90 , 270 , 540, 810, 1080, 1350, 1620, 1890, 2160 cycles of loading (T0 to T9 respectively).
Exquisite reduction of retention force became seen after ninety cycles of insertion and removal (more than 35% for zirconia bar and more than 17% for titanium bar). The lack of retention pressure continued in the course of the study to reach almost 1. Ninety-eight N for zirconia bar and 1.71 N for titanium bar on the give up of the look at (T9 after 2160 cycles of insertion and removal which become simulation of years of usage).