title: Accuracy of virtually planned and CAD/CAM-guided implant surgery on plastic models.
abstract: BACKGROUND
  Studies of guided implant surgery have identified various methods that could influence accuracy. The present investigation was designed to limit the factors contributing to accuracy and to compare the results for 5 different surgeons.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate any deviation between virtually planned and actually placed implants by 5 surgeons performing computer-aided design/computer-aided manufacturing (CAD/CAM)-guided implant surgery on duplicate plastic models.
  
  
  METHODS
  Five surgeons participated in the study, and each received 5 plastic maxillary jaw models. Thus, 25 models were used for implant placement with CAD/CAM-fabricated surgical templates. Each model contained 6 implants; therefore, a total of 150 implants were placed. The virtually planned and actually placed implant positions were compared for the apex, hexagon, depth, and angle with 2 computed tomography scans that were matched with voxel-based registration software. In addition, any differences in the 4 parameters among the surgeons were statistically tested. The data were analyzed with the t test, ANOVA, and Scheffé test (α=.05).
  
  
  RESULTS
  A statistically significant difference between the virtually planned and actually placed implant positions was observed for 3 of the 4 outcome variables (the apex, hexagon, and depth; P<.05). A statistically significant difference was also noted among all surgeons regarding the positions of the apex, depth, and angle.
  
  
  CONCLUSIONS
  The results of this study provide a better understanding of the differences in accuracy between surgeons when using a CAD/CAM surgical technique. There was a significant difference between the virtually planned and actually placed implant positions and between the surgeons for some of the variable parameters analyzed. The null hypothesis was thus rejected.
authors.affiliation: Research Fellow, Department of Dental Medicine, Division of Image and Functional Odontology, Karolinska Institute, Huddinge, Sweden. Electronic address: andreas.pettersson@ki.se.
authors.forename: Andreas
authors.initials: A
authors.lastname: Pettersson
authors.affiliation: Research Fellow, Department of Product and Production Development, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: Timo
authors.initials: T
authors.lastname: Kero
authors.affiliation: Professor and Head, Department of Product and Production Development; Director of Wingquist Laboratory, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: Rikard
authors.initials: R
authors.lastname: Söderberg
authors.affiliation: Associate Professor and Head, Department of Dental Medicine, Division of Image and Functional Odontology, Karolinska Institute, Huddinge, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Näsström
mesh_terms: D002983:Clinical Competence / Q000592:standards; D017076:Computer-Aided Design / Q000706:statistics & numerical data*; D059605:Dental Implant-Abutment Design; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000706:statistics & numerical data; D015921:Dental Implants; D003761:Dental Impression Technique; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008437:Maxilla / Q000033:anatomy & histology / Q000601:surgery; D008953:Models, Anatomic; D000066794:Oral and Maxillofacial Surgeons / Q000592:standards; D010347:Patient Care Planning; D013499:Surface Properties; D025321:Surgery, Computer-Assisted / Q000706:statistics & numerical data*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014584:User-Computer Interface
chemical_list: D015921:Dental Implants