| Overdenture: Bar with Screw-retention Bicon's abutments for screw-retained restorations are designed with a 20 degree taper of the coronal portion, so elongation or breakage of retention screws is not a problem. Flexibility is provided with two abutments with gingival cuff lengths of 3.0mm and 5.0mm and with post angles of 0 and 15 degrees. |
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1. | Radiograph of three implants with abutments for screw-retained restorations. |
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2. | Occlusal view of abutments revealing threaded bore for screw retention. |
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3. | Buccal view of abutments revealing the 20 degree taper of the coronal portion. |
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4. | A 10.0mm coping screw is being inserted to retain a plastic transfer coping. |
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5. | Third coping screw being fastened to abutment. Parallellism of abutments is easily evaluated prior to making an open tray impression for the pickup of the three plastic transfer copings. |
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6. | The three coping screws are being unfastened through the open tray impression to allow for the pickup of the plastic transfer copings in the impression. |
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7. | A work in progress screw is being fastened to the abutment for the period of time that the overdenture bar is being fabricated in the laboratory. |
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8. | Crestal view of impression with three plastic transfer copings. |
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9. | Brass abutment analog being inserted into plastic coping within impression. |
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10. | Coping screw being fastened to retain the brass abutment analog in the proper position during the pouring of a stone model. |
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11. | Three abutment analogs in a stone model. |
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12. | Cast overdenture bar seated on brass abutment analogs. |
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13. | Crestal view of overdenture bar with three retention screws. |
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14. | Overdenture bar being seated on abutments to evaluate for a passive seating. |
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15. | Since retention screws have only a few threads, they confirm the passive fit of the prosthesis. If their threads do not engage the abutment, the clinician knows that the prosthesis is not passively seated. |
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16. | Overdenture bar fastened onto three abutments for screw retention. |
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17. | Radiograph of screw retained overdenture bar on three Bicon implants. |
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