Rana Mohamed Abd El-Hamed Shehata .

ABSTRACT To investigate and compare the changes in retentive forces and wear resistance of two attachment systems Nova-loc& telescope with different design and overlaying patrices over two un splinted implant supported mandibular over denture under short-term simulated function. Two models carrying a two-implant analogue with two different types of overlying patrices Telescope and Nova loc over which an acrylic complete denture was constructed with picked up corresponding matrices. The tensile forces were applied using a universal testing machine to evaluate retention force, and digital microscope was utilities to evaluate wear resistance. Evaluation of retentive force & wear resistance of telescopic and Nova-loc IODs was carried out at five-time intervals; at baseline and after they are subjected to cyclic loading under at 500, 1000, 1500 and 2000 cycles of repeated insertion and removal. Retentive values were recorded by using independent t-test which revealed the retention of the group I (Telescope) was significantly higher (p<0.05) than those of group II (Nova loc) at baseline & after exposure to different cyclic loading (500- 1000- 1500- 2000). Regarding the wear, comparison of wear (wear change) of both groups was performed by using t-test between mean difference which revealed that the group I (telescope) was significantly higher than group II (Nova-loc). Regarding to Telescope and Nova-loc systems have satisfactory retentive forces, However, short-term successful clinical use in implant overdentures. Nova loc attachments are promising to be successfully used in implant overdentures as the Telescopic coping attachments with satisfactory retention. However, the retention value of Telescope higher than Nova loc, the wear behavior of Nova-loc lesser than Telescope due to the peek material. Keywords: Retention, Wear, Implant, Overdenture, Telescopic attachment, Novaloc attachment