title: A Current Perspective on Screw-Retained Single-Implant Restorations: A Review of Pertinent Literature.
abstract: OBJECTIVE
  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.
  
  
  BACKGROUND
  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.
  
  
  CONCLUSIONS
  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).
authors.affiliation: Board Certified Prosthodontist, 23 Main Street, Suite 303, Hilton Head Island, SC, 29926, USA.
authors.forename: George
authors.initials: G
authors.lastname: Priest
mesh_terms: D001863:Bone Screws; D003442:Crowns; D003738:Dental Cements; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D004955:Esthetics, Dental; D006801:Humans; D015040:Zirconium
chemical_list: D003738:Dental Cements; C493120:lithia disilicate; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide