title: Are Zirconia Implant Abutments Safe and Predictable in Posterior Regions? A Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  This systematic review aimed to evaluate whether the survival rate and predictability of zirconia abutments are similar to those of titanium abutments for single implant crowns in the posterior area.
  
  
  METHODS
  A systematic search of two databases (Medline/PubMed and Cochrane Library) was performed by two independent reviewers for articles published between January 2004 and July 2014. The electronic search was complemented by a hand search of the following journals from the same period: Journal of Periodontology, Clinical Oral Implants Research, International Journal of Prosthodontics, and International Journal of Oral and Maxillofacial Implants. Studies included were published in English, evaluated single implant crowns, and performed a mean observation ≥ 1 year. Any disagreement between the reviewers was solved by means of a discussion. Forest plot and funnel were used to compare zirconia and titanium abutments.
  
  
  RESULTS
  The search strategy identified 669 studies. Of these, 11 studies were included and only 6 studies were selected for meta-analysis. The pooled results for fixed implant single crowns in posterior areas showed a 5-year success rate of 99.3% for zirconia abutments and 99.57% for titanium abutments. There was no statistical difference regarding veneer failure (P = .26). The pooled results of these studies showed that the mean bone loss was 0.38 ± 0.87 mm for zirconia and 0.2 ± 0.13 mm for titanium abutments.
  
  
  CONCLUSIONS
  The use of zirconia abutments for single implant-fixed crowns in posterior regions is questionable due to the absence of long-term data. The short-term results of zirconia abutments regarding mechanical and biologic responses are similar to titanium abutments. Caution when using zirconia abutments in posterior regions is necessary until further clinical evidence shows favorable long-term results.
authors.forename: Aljomar José
authors.initials: AJ
authors.lastname: Vechiato-Filho
authors.forename: Aldiéris Alves
authors.initials: AA
authors.lastname: Pesqueira
authors.forename: Grace M
authors.initials: GM
authors.lastname: De Souza
authors.forename: Daniela Micheline
authors.initials: DM
authors.lastname: dos Santos
authors.forename: Eduardo Piza
authors.initials: EP
authors.lastname: Pellizzer
authors.forename: Marcelo Coelho
authors.initials: MC
authors.lastname: Goiato
mesh_terms: D000044:Dental Abutments; D003724:Dental Arch / Q000033:anatomy & histology; D019250:Dental Implants, Single-Tooth; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D006801:Humans; D012449:Safety; D014025:Titanium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide