title: Clinical outcomes of implant abutments in the anterior region: a systematic review.
abstract: BACKGROUND
  The clinical outcomes of anterior implant abutments are not well reported. Purpose of the Study To systematically review the existing literature to identify survival, mechanical, biological, and esthetic outcomes of anterior implant abutments.
  
  
  METHODS
  An electronic search was performed using PubMed/MEDLINE with specific search terms and predetermined criteria. After application of inclusion and exclusion criteria, the final list of articles was reviewed in-depth to meet the objectives of this review.
  
  
  RESULTS
  Systematic application of inclusion and exclusion criteria resulted in identification of 27 studies that described outcomes of anterior implant abutments. Because of substantial heterogeneity of data, true survival, or cumulative survival of abutments could not be calculated. However, the mean failure of abutments was 1.15%, attributable to fractures restricted to ceramic abutments. Mechanical complications included abutment screw loosening, primarily restricted to external hex implants. Biological complications included fistulas and mucosal recession. Esthetic outcomes showed lesser gingival discoloration for zirconia abutments compared with metal abutments.
  
  
  CONCLUSIONS
  Minimal anterior abutment fractures have been reported and are restricted to ceramic abutments. Studies using spectrophotometry showed lesser gingival discoloration with zirconia abutments, but there is no evidence for difference in patient's esthetic satisfaction between ceramic and metal abutments.
  
  
  CONCLUSIONS
  For the anterior region, selection of an implant with internal connection and a customized metal abutment (titanium or cast metal) can have the least mechanical complications. Limited existing clinical data indicate reduced peri-implant mucosal discoloration from zirconia abutments, which may be preferable over metal abutments, in patients with thinner mucosal tissues or patients with high or gummy smiles.
authors.affiliation: Post-Graduate Prosthodontics, Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, CT 06030, USA. avinashbidra@yahoo.com
authors.forename: Avinash S
authors.initials: AS
authors.lastname: Bidra
authors.forename: Patchanee
authors.initials: P
authors.lastname: Rungruanganunt
mesh_terms: D001696:Biomechanical Phenomena; D003724:Dental Arch / Q000601:surgery; D059605:Dental Implant-Abutment Design / Q000009:adverse effects; D003764:Dental Materials / Q000737:chemistry; D019232:Dental Restoration Failure; D004955:Esthetics, Dental; D006801:Humans; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D003764:Dental Materials