title: Accuracy of miniscrew surgical guides assessed from cone-beam computed tomography and digital models.
abstract: BACKGROUND
  Several methods are available to enhance the precision of miniscrew placement. The use of surgical guides based on cone-beam computed tomography is indicated especially in patients with risky or difficult anatomic situations. The purpose of this study was to evaluate the accuracy of miniscrew placement by using surgical guides developed with computer-aided design and manufacturing techniques.
  
  
  METHODS
  Miniscrews were placed in cadaver maxillae using stereolithographic computer-aided design and manufacturing techniques with assistance from surgical guides (surgical guide group, n = 25) or periapical x-rays (control group, n = 20). Insertion sites were selected using a 3-dimensional surgical planning program by fusing maxillary digital model images and cone-beam computed tomography images. Deviations between actual and planned placements were measured as 3-dimensional angular deviations and distance (coronal and apical) deviations.
  
  
  RESULTS
  In the surgical guide group, the angular deviation was a median of 3.14° (range, 1.02°-10.9°), and the mesiodistal deviations in the coronal and apical areas were medians of 0.29 mm (range, 0.03-0.73 mm) and 0.21 mm (range, 0.03-0.97 mm), respectively. The deviations differed significantly between operators in the control group, but not in the surgical guide group. In the surgical guide group, there was no root damage from miniscrew placement, and 84% of the miniscrews were placed without contacting adjacent anatomic structures. In the control group, 50% of the miniscrews were placed between the roots (P <0.05).
  
  
  CONCLUSIONS
  Surgical guide accuracy was improved when digital model imaging was used. Miniscrews were placed more accurately when using surgical guides than when using a direct method.
authors.affiliation: Department of Orthodontics, Yonsei University, College of Dentistry, Seoul, South Korea.
authors.forename: Mi-Ju
authors.initials: MJ
authors.lastname: Bae
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Jong-Tae
authors.initials: JT
authors.lastname: Park
authors.forename: Jung-Yul
authors.initials: JY
authors.lastname: Cha
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Hyung-Seog
authors.initials: HS
authors.lastname: Yu
authors.forename: Chung-Ju
authors.initials: CJ
authors.lastname: Hwang
mesh_terms: D001863:Bone Screws; D002102:Cadaver; D017076:Computer-Aided Design; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery*; D003765:Models, Dental; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000379:methods; D010347:Patient Care Planning; D016300:Radiography, Bitewing / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014092:Tooth Root / Q000000981:diagnostic imaging; D014584:User-Computer Interface