title: Radiographic verification of implant abutment seating.
abstract: BACKGROUND
  It is possible to incorrectly seat an abutment on an external hex implant.
  
  
  OBJECTIVE
  This study investigated the theoretical and practical limits of radiographic verification of the complete seating of implant abutments on external hex implants.
  
  
  METHODS
  A positioning device that could accurately place the film and/or tube head in any vertical relation desired relative to the implant and abutment was fabricated. For all records, a standard abutment was secured to the implant in both a fully seated position (closed) and with the abutment turned approximately 30 degrees and seated atop the implant external hex (open). Digital radiographs were made with the tube head fixed perpendicular to the implant and the film angled at 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees. The film was then positioned parallel to the implant and the tube head was angled at 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees. An image of each position was shown to 36 dentists and they were asked if the image was diagnostic for determining the status of the implant/abutment interface.
  
  
  RESULTS
  The data were analyzed with a computer statistics program. The group with the tube head changed was analyzed with the Cochran's Q test and revealed a statistically significant (p < 0.0001) change in the diagnostic value of radiographs beginning at 20 degrees. The group with the film angle changed was analyzed with a Pearson chi-square and showed no statistical difference (p = 0.394) for the diagnostic value of any of the film angles.
  
  
  CONCLUSIONS
  Maintaining the tube head to less than 20 degrees from perpendicular to the long axis of the implant resulted in a diagnostic radiograph, regardless of the angle of the film.
authors.affiliation: Maxillofacial Prosthetics/Dental Oncology, U.S. Army Dental Activity, Fort Gordon, Ga., USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Cameron
authors.forename: A
authors.initials: A
authors.lastname: Joyce
authors.forename: J S
authors.initials: JS
authors.lastname: Brousseau
authors.forename: M H
authors.initials: MH
authors.lastname: Parker
mesh_terms: D016009:Chi-Square Distribution; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D006801:Humans; D017755:Prosthesis Fitting; D011861:Radiography, Dental / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D015921:Dental Implants