Angulated Screw-retained Crowns Following Immediate Implant Placement

There are two choices of restorations and implant abutments connection now: cemented and screw-retained.The excess cement, which would be difficult to completely remove, might lead to series of biological complications. The angulated screw channel (ASC) abutments, which recently introduced by Nobel Biocare , largely address the problem with visible screw access that may compromise esthetics. However, all of the present studies were clinical reports, thus the clinical efficacy of ASC abutments still needs the verification of evidence-based medicine with larger sample. Therefore, we designed a randomized controlled clinical trial study, aiming to verify the clinical efficacy of the ASC abutments by comparing screw-retained (with ASC abutments) single implant crowns with cemented ones in esthetic region.