title: Angled implant abutments: a practical application of available knowledge.
abstract: BACKGROUND
  When dental implants are not placed parallel to adjacent teeth or contiguous implants, the clinician can use angled abutments to achieve proper restorative contours. However, increased stresses on implants and bone have been associated with use of angled abutments. In this regard, there are unresolved issues concerning implant survival and potential prosthetic complications that can arise when angled abutments are used to align prosthetic positions.
  
  
  METHODS
  The authors searched the dental literature for clinical trials that appraised the survival rate and complications (biological and technical) associated with pros-theses that are supported by angled abutments.
  
  
  RESULTS
  The results of photoelastic stress assessments, finite element analysis and strain-gauge studies indicated that increased abutment angulations result in the placement of a greater amount of stress on prostheses and the surrounding bone than that associated with straight abutments. However, survival studies did not demonstrate a significant decrease of prostheses' longevity associated with angled abutments. Furthermore, there was no additional bone loss adjacent to implants that supported angled abutments compared with straight abutments, and angled abutments did not manifest an increased incidence of screw loosening.
  
  
  CONCLUSIONS
  The use of angled abutments facilitates paralleling nonaligned implants, thereby making prosthesis fabrication easier. These abutments also can aid the clinician in avoiding anatomical structures when placing the implants. In addition, use of angled abutments can reduce treatment time, fees and the need to perform guided bone regeneration procedures.
authors.affiliation: Implant Fellowship Program, College of Dental Medicine, Columbia University, New York City, NY, USA. docsamurai@si.rr.com
authors.forename: John
authors.initials: J
authors.lastname: Cavallaro
authors.forename: Gary
authors.initials: G
authors.lastname: Greenstein
mesh_terms: D000539:Alveolar Process / Q000503:physiopathology; D001696:Biomechanical Phenomena; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D006801:Humans; D013314:Stress, Mechanical; D016019:Survival Analysis
chemical_list: D015921:Dental Implants