Evaluation of retention of mandibular implant overdenture retained by three different attachment systems : An in vitro study / Mostafa Said Hosney ; Supervised Mahmoud Mokhtar Elfar , Amr Hosny Elkhadem

Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

An in-vitro study was done to test the efficiency of adding vertical walls to magnet attachment reassemble telescope design. An epoxy model was prepared with two implants in canine area. A denture was constructed on the model with three hooks, one in the geometric center of the denture, the other in the middle of the anterior area (midline) and the last in posterior premolar area. The forces on the denture were applied through the hooks. Three attachments were constructed and picked up in the denture to be tested by applying tensile forces using a universal testing machine. In order, telescope attachment was constructed and picked up in the denture, then magnet with a vertical wall was constructed and the last was magnet without a vertical wall. For telescope attachment abutment with 5mm length and 1-degree taper was used. The same abutment was used for the magnet with a vertical wall after decrease the length to 2.5mm height. Stoke magnetic flat keeper was used for magnet attachment. Every attachment subjected to was subjected to four types of tensile forces. Geometric center vertical force, vertical anterior force, vertical posterior force and premolar area oblique force. Retention values were calculated and results were analyzed. The study concludes that: Telescope has the highest retention values then magnet with. Adding vertical wall to the magnet attachment design was significantly increase the retention values. In oblique forces, which was the most force type resemble the forces in the oral cavity, vertical wall increased significantly the resistance to the denture dislodgment and retention break up

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