Rokiya Mansour Mohamad Alshibi, Radwa Mohsen Omera And Moustafa Abdou Elsyad,

ABSTRACT
PURPOSE: The Aim Of This Study Was To Evaluate, The Effect Of Different Degrees Of Distal Implants Inclination On The Retention And Stability Of Two-implant Mandibular Overdenture With Locator Attachments.

Materials and Methods: Four Duplicated Clear Acrylic Experimental Models Were Constructed. The Models Were Covered By Resilient Silicone To Simulate The Oral Mucosa. In The Canine Regions Of Each Model, Two Recesses Were Prepared With Following Degrees Of Distal Implant Inclination: Group I (0 O ,control), Group II ( 5 O), Group III(10 O), And Group IV (20 O). Four Acrylic, Metal Reinforced Overdenture Was Fabricated And Connected To The Implants Using Locator Attachments. Using The Universal Testing Machine, Vertically Oriented 4 Points Tensile Loads Was Applied To A Metal Plate Attached To The Model With 4 Metal Chains Until The Attachments Separated From The Abutments.The Initial Retentive Force(maximum Dislodging Force) And Final Retention After 540 Cycles Of Insertions And Removals Were Measured For Each Group.

Results: For Initial Retentive Forces And Retentive Forces After Repeated Insertions And Removals, 5 Degree Inclination Recorded The Highest Retentive Forces, Followed By 10 Degrees, Then 0 Degrees And 20 Degrees Recorded The Lowest Retention Values. Locator Transparent Recorded The Highest Retentive Forces, Followed By Locator Pink, Locator Green, Locator Blue And Locator Red Recorded The Lowest Retention Values. Conclusion: Comparing Nylon Inserts, Transparent Inserts Are Recommended To Retain Overdentures With Parallel(0?) And Distal Implant Inclination With A Slight Degree(5?), While For A High Degree Of Inclination (20?), Blue And Pink Inserts Are Recommended Instead Of Transparent Inserts.