title: Measurement of the buccolingual inclination of teeth: manual technique vs 3-dimensional software.
abstract: BACKGROUND
  In this study, we aimed to measure the inclination of teeth on dental casts by a manual technique with the tooth inclination protractor (TIP; MBI, Newport, United Kingdom) and a newly designed 3-dimensional (3D) software program. The correlation of the 2 techniques was evaluated, and the reliability of each technique was assessed separately.
  
  
  METHODS
  This study was conducted on 36 dental casts of normal, well-aligned Class I occlusions; we assessed 432 teeth. All casts had a normal Class I occlusion. After determining the facial axis of the clinical crown and the facial axis points on the dental casts, we measured the inclinations of the incisors and posterior teeth up to the first molars in each dental arch relative to Andrews' occlusal plane and the posterior occlusal plane using the TIP. Moreover, the casts were scanned by a structured-light 3D scanner. The inclination of teeth relative to the occlusal plane was determined using the new software. To assess the reliability, measurements of all teeth from 15 casts were repeated twice by the 2 methods. Intraclass correlation coefficient and Dahlberg's formula were used for calculation of correlation and reliability.
  
  
  RESULTS
  Overall, the 2 techniques were not significantly different in the measurements of the inclinations of the teeth in both jaws. The ranges of Dahlberg's formula were 3.1° to 5.8° for the maxilla and 3.3° to 5.9° for the mandible. The overall correlation of the 2 techniques according to the intraclass correlation coefficient was 0.91. For calculation of reliability, the intraclass correlation coefficients for the TIP and the 3D method were 0.73 and 0.82, respectively.
  
  
  CONCLUSIONS
  The TIP and the 3D software showed a high correlation for measurement of the inclinations of maxillary and mandibular teeth relative to the occlusal plane. Also, the reproducibility of the measurements in each method was high.
authors.affiliation: Associate professor, Dentofacial Deformities Research Center, Research Institute of Dental Sciences, and Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mahtab
authors.initials: M
authors.lastname: Nouri
authors.affiliation: Research assistant, Computer Engineering Department, Sharif University of Technology, and School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Abdi
authors.affiliation: Postgraduate student, Department of Orthodontics, Dental Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Electronic address: dr.arash.farzan@gmail.com.
authors.forename: Arash
authors.initials: A
authors.lastname: Farzan
authors.affiliation: Postgraduate student, Department of Operative Dentistry, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Faraneh
authors.initials: F
authors.lastname: Mokhtarpour
authors.affiliation: Associate professor, Department of Basic Sciences, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: AliReza Akbarzadeh
authors.initials: AA
authors.lastname: Baghban
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology; D003198:Computer Simulation; D003481:Cuspid / Q000033:anatomy & histology; D003766:Dental Occlusion; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D007180:Incisor / Q000033:anatomy & histology; D008334:Mandible / Q000033:anatomy & histology; D008437:Maxilla / Q000033:anatomy & histology; D008953:Models, Anatomic; D003765:Models, Dental; D008963:Molar / Q000033:anatomy & histology; D009811:Odontometry / Q000706:statistics & numerical data*; D061848:Optical Imaging / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012984:Software / Q000706:statistics & numerical data*; D019228:Tooth Crown / Q000033:anatomy & histology; D014584:User-Computer Interface