title: A systematic review of the 5-year survival and complication rates of implant-supported single crowns.
abstract: OBJECTIVE
  The objective of this systematic review was to assess the 5-year survival of implant-supported single crowns (SCs) and to describe the incidence of biological and technical complications.
  
  
  METHODS
  An electronic MEDLINE search complemented by manual searching was conducted to identify prospective and retrospective cohort studies on SCs with a mean follow-up time of at least 5 years. Failure and complication rates were analyzed using random-effects Poisson's regression models to obtain summary estimates of 5-year proportions.
  
  
  RESULTS
  Twenty-six studies from an initial yield of 3601 titles were finally selected and data were extracted. In a meta-analysis of these studies, survival of implants supporting SCs was 96.8% [95% confidence interval (CI): 95.9-97.6%] after 5 years. The survival rate of SCs supported by implants was 94.5% (95% CI: 92.5-95.9%) after 5 years of function. The survival rate of metal-ceramic crowns, 95.4% (95% CI: 93.6-96.7%), was significantly (P=0.005) higher than the survival rate, 91.2% (95% CI: 86.8-94.2%), of all-ceramic crowns. Peri-implantitis and soft tissue complications occurred adjacent to 9.7% of the SCs and 6.3% of the implants had bone loss exceeding 2 mm over the 5-year observation period. The cumulative incidence of implant fractures after 5 years was 0.14%. After 5 years, the cumulative incidence of screw or abutment loosening was 12.7% and 0.35% for screw or abutment fracture. For supra-structure-related complications, the cumulative incidence of ceramic or veneer fractures was 4.5%.
  
  
  CONCLUSIONS
  It can be concluded that after an observation period of 5 years, high survival rates for implants and implant-supported SCs can be expected. However, biological and particularly technical complications are frequent.
authors: Department of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland. jung@zzmk.unizh.ch
authors: Ronald E
authors: RE
authors: Jung
authors: Bjarni E
authors: BE
authors: Pjetursson
authors: Roland
authors: R
authors: Glauser
authors: Anja
authors: A
authors: Zembic
authors: Marcel
authors: M
authors: Zwahlen
authors: Niklaus P
authors: NP
authors: Lang
mesh_terms: D003442:Crowns / Q000706:statistics & numerical data; D003758:Dental Implantation, Endosseous / Q000009:adverse effects / Q000706:statistics & numerical data*; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects / Q000706:statistics & numerical data*; D019232:Dental Restoration Failure; D006801:Humans; D010485:Periapical Periodontitis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology; D016012:Poisson Distribution; D011859:Radiography; D016019:Survival Analysis