title: Virtually planned and template-guided implant surgery: an experimental model matching approach.
abstract: OBJECTIVE
  The objective of this study was to assess positional deviations between the implant replicas in the pre-operative plaster model created from a computer-aided design/computer-aided manufacturing (CAD/CAM) surgical template and the implant replicas in the post-operative plaster model that was made from patients' impressions taken at ≥1-year follow-up.
  
  
  METHODS
  One hundred and thirty-nine implants were inserted in 25 edentulous jaws using Nobel Guide(™). Plaster models containing the implant replicas, one created from the surgical template before surgery and the other created from patients' impressions at ≥1-year follow-up, were scanned using a measuring device. Implant positions were matched with the best-fit alignment. Deviation was calculated at the level of the hex and the apex. The results were compared with a computed tomography matching study. Data were analysed using the paired t-test (α=0.05).
  
  
  RESULTS
  There were positional deviations of implant replicas between pre- and post-operative plaster models both at the hex and the apex. The geometric mean of the deviation at the apex was 0.59 mm in the maxilla and 0.4 mm in the mandible. At the hex, it was 0.59 mm in the maxilla and 0.39 mm in the mandible.
  
  
  CONCLUSIONS
  Statistically significant differences were observed in positions between the implant replicas in the pre-operative plaster models created from a CAD/CAM surgical template and the implant replicas in the post-operative plaster models that were made from patients' impressions taken at ≥1-year follow-up. Due to the lack of reference objects in the pre- and post-operative working casts, additional refinements are required in order to validate the impression matching method and recommend the method to be used.
authors.affiliation: Department of Dental Medicine, Division of Periodontology, Karolinska Institutet, Huddinge, Sweden. ai.komiyama@me.com
authors.forename: Ai
authors.initials: A
authors.lastname: Komiyama
authors.forename: Andreas
authors.initials: A
authors.lastname: Pettersson
authors.forename: Margareta
authors.initials: M
authors.lastname: Hultin
authors.forename: Karin
authors.initials: K
authors.lastname: Näsström
authors.forename: Björn
authors.initials: B
authors.lastname: Klinge
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002133:Calcium Sulfate / Q000737:chemistry; D017076:Computer-Aided Design; D000044:Dental Abutments; D003724:Dental Arch / Q000473:pathology / Q000601:surgery; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods*; D003761:Dental Impression Technique; D003764:Dental Materials / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D057918:Fiducial Markers; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D057893:Immediate Dental Implant Loading; D007575:Jaw, Edentulous / Q000601:surgery; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008437:Maxilla / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D003765:Models, Dental; D010347:Patient Care Planning; D012984:Software; D013499:Surface Properties; D014057:Tomography, X-Ray Computed / Q000379:methods; D014584:User-Computer Interface
chemical_list: D003764:Dental Materials; D002133:Calcium Sulfate