title: Survival and Complications of Zygomatic Implants: An Updated Systematic Review.
abstract: OBJECTIVE
  To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complications based on previously published studies.
  
  
  METHODS
  An electronic search of 3 databases was performed in December 2015 and was supplemented by manual searching. Clinical series of ZIs were included. Interval survival rate and cumulative survival rate (CSR) were calculated. The untransformed proportion of complications (sinusitis, soft tissue infection, paresthesia, oroantral fistulas) was calculated by considering the prevalence reported in the studies.
  
  
  RESULTS
  Sixty-eight studies were included, comprising 4,556 ZIs in 2,161 patients with 103 failures. The 12-year CSR was 95.21%. Most failures were detected within the 6-month postsurgical period. Studies (n = 26) that exclusively evaluated immediate loading showed a statistically lower ZI failure rate than studies (n = 34) evaluating delayed loading protocols (P = .003). Studies (n = 5) evaluating ZIs for the rehabilitation of patients after maxillary resections presented lower survival rates. The probability of presenting postoperative complications with ZIs was as follows: sinusitis, 2.4% (95% confidence interval [CI], 1.8-3.0); soft tissue infection, 2.0% (95% CI, 1.2-2.8); paresthesia, 1.0% (95% CI, 0.5-1.4); and oroantral fistulas, 0.4% (95% CI, 0.1-0.6). However, these numbers might be underestimated, because many studies failed to mention the prevalence of these complications.
  
  
  CONCLUSIONS
  ZIs present a high 12-year CSR, with most failures occurring at the early stages postoperatively. The main observed complication related to ZIs was sinusitis, which can appear several years after ZI installation surgery.
authors.affiliation: PhD student, Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden. Electronic address: bruno.chrcanovic@mah.se.
authors.forename: Bruno Ramos
authors.initials: BR
authors.lastname: Chrcanovic
authors.affiliation: Retired Professor and former Department Head, Department of Biomaterials, Göteborg University, Göteborg; Guest Professor, Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Albrektsson
authors.affiliation: Professor and Department Head, Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors.forename: Ann
authors.initials: A
authors.lastname: Wennerberg
mesh_terms: D016301:Alveolar Bone Loss / Q000601:surgery*; D001284:Atrophy; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019232:Dental Restoration Failure; D006801:Humans; D008439:Maxillary Diseases / Q000601:surgery*; D011183:Postoperative Complications; D016019:Survival Analysis; D015050:Zygoma / Q000601:surgery*