Marginal Discrepancy of Screw-Retained and Cemented Metal-Ceramic Crowns on Implant Abutments

This in vitro study quantified the marginal discrepancy of the implant-to-prosthetic-crown interface on nonsubmerged dental implants restored with either a cemented or a screw-retained approach. Metal-ceramic crowns were fabricated for 20 ITI 4.1 X 10 mm solid-screw titanium implants. Ten implants received octa abutments and screw-retained crowns fabricated on premachined gold cylinders. The remaining 10 implants were restored with 5.5-mm solid abutments and metal-ceramic crowns cemented alternately with a glass-ionomer or a zinc phosphate luting agent. Inspection of the implant-crown interface was conducted using light microscopy under X50 magnification at selected stages in the process of crown fabrication. Statistical analysis revealed a significant difference (P .001) in the mean marginal fit between screw-retained (8.5 ± 5.7 µm) and luted implant-supported crowns. This difference was observed both before (54.4 ± 18.1 µm) and after cementation with glass-ionomer (57.4 ± 20.2 µm) or zinc phosphate (67.4 ± 15.9 µm). Schlagwörter: cement, dental implant, fixed prostheses, marginal discrepancy, screw-retained