title: Implant-level prostheses in the edentulous maxilla: a comparison with conventional abutment-level prostheses after 5 years of use.
abstract: OBJECTIVE
  Long-term comparisons of frameworks at the implant or abutment level are not available, and knowledge of the clinical function of cobalt-chromium (Co-Cr) alloy frameworks is limited. Primarily, the aim of this study was to compare the 5-year clinical performance of frameworks with or without abutment connections to implants. Secondly, the outcomes of prostheses made from Co-Cr alloy with porcelain veneers to those made of commercially pure titanium (CP Ti) with acrylic veneers were compared.
  
  
  METHODS
  The test groups comprised patients treated with screw-retained fixed prostheses made at the implant level according to the Cresco method in either dental porcelain-veneered Co-Cr alloy (n = 15) or acrylic-veneered CP Ti (n = 25). A control group of 40 randomly selected patients were provided with prostheses made at the standard abutment level in CP Ti with acrylic veneers. For all patients, clinical and radiologic 5-year data were retrospectively collected and evaluated.
  
  
  RESULTS
  Five-year implant cumulative survival rates (CSRs) were 98.6% and 97.6% for test and control groups, respectively (P > .05). No major differences in bone level were demonstrated between the groups after 5 years (P > .05). Significantly more complications occurred in the test groups compared to the control group (P < .01), with the most common complications being mucositis and fracture of veneers.
  
  
  CONCLUSIONS
  After 5 years, the clinical outcomes of implant-level prostheses made of porcelain-veneered Co-Cr or acrylic-veneered CP Ti seem comparable to acrylic-veneered titanium prostheses made at the standard abutment level regarding implant CSR and bone levels. However, more complications were registered in implant-level prostheses compared to the standard abutment-level prostheses.
authors.affiliation: The Malar Hospital, Eskilstuna, Sweden. lars.hjalmarsson@dll.se
authors.forename: Lars
authors.initials: L
authors.lastname: Hjalmarsson
authors.forename: Jan-Ivan
authors.initials: JI
authors.lastname: Smedberg
authors.forename: Mattias
authors.initials: M
authors.lastname: Pettersson
authors.forename: Torsten
authors.initials: T
authors.lastname: Jemt
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000209:etiology; D002858:Chromium Alloys / Q000737:chemistry; D000044:Dental Abutments; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003801:Dental Veneers; D003779:Denture Design; D003781:Denture Retention; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation* / Q000601:surgery; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D016300:Radiography, Bitewing; D012189:Retrospective Studies; D013280:Stomatitis / Q000209:etiology; D016019:Survival Analysis; D014025:Titanium / Q000737:chemistry; D016896:Treatment Outcome
chemical_list: D000180:Acrylic Resins; D002858:Chromium Alloys; D015921:Dental Implants; D003764:Dental Materials; D003776:Dental Porcelain; D014025:Titanium