A Current Perspective on Screw-Retained Single-Implant Restorations: A Review of Pertinent Literature.

Abstract

There is a trend toward increased use of screw-retained single-implant restorations. A comprehensive literature review was undertaken to examine the data related to screw- and cement-retention and to objectively evaluate the innovations in implant dentistry that have led to this resurgence. When comparing the two options, survival and complication rates are similar, bone and soft-tissue levels are comparable, and zirconia offers esthetic advantages for both selections. Zirconia abutments with bonded titanium inserts provide esthetic alternatives to titanium abutments for both choices. Bone- and soft-tissue responses are similar, but residual cement of cement-retained restorations is associated with significant soft- and hard-tissue complications. The potential weakness of ceramic discontinuity of screw-access openings can be lessened by the incorporation of stronger ceramic materials such as zirconia and lithium disilicate. The overriding remaining indication for cement-retained restorations is to compensate for angled implants. Screw-retained single-implant crowns should be reconsidered for many clinical situations for the following reasons: Predictable retention and retrievability No potential for the biologic consequences associated with residual cement As with cement-retained restorations, the choice between metal ceramics or all ceramics Only one margin, at the implant/abutment interface A single abutment/crown ceramic margin that can extend gingivally to the implant interface Nearly imperceptible blend of a composite resin in ceramic abutment access openings One component instead of two, which may simplify the restorative process CLINICAL SIGNIFICANCE: Innovations in implant and ceramic technology now give screw-retained prostheses the potential for esthetic, functional, and biologic outcomes that are comparable to those for cement-retained prostheses, while providing the advantages of predictable retrievability and avoidance of residual cement. Angled implants, however, remain a major indication for cement-retained single-implant prostheses. (J Esthet Restor Dent 29:161-171, 2017).