Gehan Fekry Mohammed, Emad Mohamed Tolba, Ahmed Gamal Ahmed Hassan And Shaima?a Ahmed Aly,

ABSTRACT
An In-vitro Study Was Conducted Two Compare Between The Retentive Forces Of Two Different Treatment Modalities For Implant Supported Overdenture. First Treatment Modality Was Ball And Socket Implant Retained Overdenture, While The Second One Was Telescopic Crowns.

Materials and Methods: An Acrylic Resin Model Was Produced From A Commercially Available Mould And Two Identical Implants Were Inserted At The Canine Area Bilaterally. Attachments Were Embedded In Experimental Overdenture Designed To Be Dislodged From The Model By A Universal Testing Machine. A Universal Testing Machine Was Used To Test The Retention Of The Telescopic Crowns And Ball And Socket Systems At The Zero Level (T0) And After 30 , 300 , 600, 1200, 1500, 1800, 2100 Cycles Of Loading ( T1 To T7 Respectively).

Results: In General A Reduction Of Retention Force Magnitude With Time (insertion And Removal Cycles) For Both Types Of Attachments Was Observed. The Values Recorded At T0 Were Significantly Higher Than All Other Values And A Great Reduction Of Retentive Force Occurred With Time. At The Of The Study; The Telescopic Crowns Lost More Than 90% Of The Recorded Forces At Zero Level; While The Ball And Socket Attachments Lost More Than 65% From The Zero Level Retentive Forces. Conclusion: Under The Limitations Of This Study We Can Conclude That: The Retention Force Of Ball And Socket Attachments Are Greater Than Those Of Co-Cr Conus Telescopic Crowns At Any Given Cycle Of Insertion And Removal.