Abstract:
Aim of the study:
To evaluate the effect of using two different attachment systems on marginal bone height & patient satisfaction in two implant retained mandibular overdentures (IOD) with cantilever extension.
Materials & Methods:
Fourteen completely edentulous patients were selected from the out-patient clinic, Faculty of Dentistry, Beni-Suef University. Patients were rehabilitated with maxillary complete denture & mandibular implant overdenture with two different attachment systems. Group (I): Received two IOD with cantilevered bar-clip attachment. Group (II): Received two IOD with cantilevered bar with ball attachment. Patients were recalled at 3, 6, 9 & 12 months to evaluate marginal bone loss as well as patient's satisfaction.
Results: The mean marginal bone height loss after 3 month for Group- I (Bar & clip attachment) was 0.3889mm ± 0.3915 while for Group II (Bar -ball & socket attachment) was 0.3954mm ± 0.06046. After 6 month, the mean bone loss for Group (I) was 0.6786mm ± 0.06098, while for Group (II) was 0.7056mm ± 0.4157. After 9 month, the mean bone loss for Group (I) was 0.7897mm ± 0.01378 while for Group (II) was 0.7984mm ± 0.02584. After 12 month, the mean bone loss for Group (I) was 0.8556mm ± 0.33802 while for Group (II) was 1.0154mm ± 0.08415.
Regarding patient satisfaction: there was a significant difference during the follow-up intervals in both groups.

Conclusions:
• Bar/clip attachment may provide better stress distribution &less marginal bone loss than bar/ball attachment.
• Patients may be more satisfied with bar/ball attachment than bar/clip attachment.