title: Effects of minute misregistrations of prefabricated markers for image-guided dental implant surgery: an analytical evaluation.
abstract: OBJECTIVE
  The goal of the present study was to develop a theoretical analysis of errors in implant position, which can occur owing to minute registration errors of a reference marker in a cone beam computed tomography volume when inserting an implant with a surgical stent.
  
  
  METHODS
  A virtual dental-arch model was created using anatomic data derived from the literature. Basic trigonometry was used to compute effects of defined minute registration errors of only voxel size. The errors occurring at the implant's neck and apex both in horizontal as in vertical direction were computed for mean ±95%-confidence intervals of jaw width and length and typical implant lengths (8, 10 and 12 mm).
  
  
  RESULTS
  Largest errors occur in vertical direction for larger voxel sizes and for greater arch dimensions. For a 10 mm implant in the frontal region, these can amount to a mean of 0.716 mm (range: 0.201-1.533 mm). Horizontal errors at the neck are negligible, with a mean overall deviation of 0.009 mm (range: 0.001-0.034 mm). Errors increase with distance to the registration marker and voxel size and are affected by implant length.
  
  
  CONCLUSIONS
  Our study shows that minute and realistic errors occurring in the automated registration of a reference object have an impact on the implant's position and angulation. These errors occur in the fundamental initial step in the long planning chain; thus, they are critical and should be made aware to users of these systems.
authors.affiliation: Department of Oral Surgery (and Oral Radiology), University Medical, Center of the Johannes Gutenberg-University, Mainz, Germany.
authors.forename: Lorenz L
authors.initials: LL
authors.lastname: Rußig
authors.forename: Ralf K W
authors.initials: RK
authors.lastname: Schulze
mesh_terms: D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D006801:Humans; D021621:Imaging, Three-Dimensional; D003765:Models, Dental; D010347:Patient Care Planning; D025321:Surgery, Computer-Assisted / Q000379:methods*
chemical_list: D015921:Dental Implants