title: Quantitative evaluation of maxillary interradicular bone with cone-beam computed tomography for bicortical placement of orthodontic mini-implants.
abstract: BACKGROUND
  The purpose of this study was to propose a protocol for safe bicortical placement of mini-implants by measuring the interradicular spaces of the maxillary teeth and the bone quality.
  
  
  METHODS
  Cone-beam computed tomography data were obtained from 50 adults. Three-dimensional reconstructions and measurements were made with SimplantPro software (Materialise, Leuven, Belgium). For each interradicular site, the bone thicknesses and interradicular distances at the planes 1.5, 3, 6, and 9 mm above the cementoenamel junction were measured. Standard bone units were defined to evaluate the influences of bone density and the different placement patterns on the stability of the mini-implants.
  
  
  RESULTS
  The safe interradicular sites in the maxilla for bicortical placement of 1.5-mm-diameter mini-implants were in all planes between the first and second premolars, and between the second premolar and the first molar. The safe palatal sites were between the first and second molars, and the safe labial sites of the 9-mm plane were between the central incisors, and between the lateral incisor and the canine. The safe buccal sites of the 6- and 9-mm planes were between the first and second molars, and the safe buccal sites of the 3-, 6-, and 9-mm planes were between the canine and the first premolar. Most bone thicknesses were from 8 to 12 mm. The optimal placement angle between the second premolar and the first molar was 58°. Bicortical placement could have more standard bone units than unicortical placement in the maxilla.
  
  
  CONCLUSIONS
  Bicortical placement would be more stable in the maxilla. For the site between the molars, special care should be taken at a plane higher than 6 mm to prevent maxillary sinus penetration. The most favorable interradicular area in the maxilla was between the second premolar and the first molar.
authors.affiliation: Postgraduate student, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China; 264th Hospital of Chinese People's Liberation Army, Taiyuan, Shanxi, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Associate professor, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Li
authors.affiliation: Associate professor, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Cao
authors.affiliation: Postgraduate student, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Postgraduate student, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.affiliation: Associate professor, Department of Orthodontics, Hospital of Stomatology, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Xuepeng
authors.initials: X
authors.lastname: Chen
authors.affiliation: Postgraduate student, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Le
authors.initials: L
authors.lastname: Yang
authors.affiliation: Attending doctor, 264th Hospital of Chinese People's Liberation Army, Taiyuan, Shanxi, China.
authors.forename: Weiran
authors.initials: W
authors.lastname: Gao
authors.affiliation: Chair, Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pa.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Petrone
authors.affiliation: Professor and head, Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China. Electronic address: dingyin@fmmu.edu.cn.
authors.forename: Yin
authors.initials: Y
authors.lastname: Ding
mesh_terms: D000293:Adolescent; D000328:Adult; D000539:Alveolar Process / Q000000981:diagnostic imaging; D001641:Bicuspid / Q000000981:diagnostic imaging; D015519:Bone Density / Q000502:physiology; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003481:Cuspid / Q000000981:diagnostic imaging; D003724:Dental Arch / Q000000981:diagnostic imaging; D015921:Dental Implants; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000000981:diagnostic imaging; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging*; D008443:Maxillary Sinus / Q000000981:diagnostic imaging; D008904:Miniaturization; D008963:Molar / Q000000981:diagnostic imaging; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000379:methods; D019237:Tooth Cervix / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000000981:diagnostic imaging; D055815:Young Adult
chemical_list: D015921:Dental Implants