title: [Comparison between the tooth length measured by cone-beam CT and the tooth length measured with vernier caliper].
abstract: OBJECTIVE
  To evaluate the accuracy of cone-bean CT (CBCT) on the measurement of the tooth length.
  
  
  METHODS
  One hundred and sixty single root premolars extracted for orthodontic purposes were selected. The tooth length was measured with vernier caliper. The premolars were divided into 10 groups randomly, 16 premolars in each group.In each group, the teeth were lined in molar area, premolar area, canine area and anterior tooth area in maxilla and mandible. Then CBCT was taken, and the tooth length was measured using the software supplied by the manufacturer in coronal and sagittal plane. Accuracy was compared between vernier caliper measurement and CBCT measurement.
  
  
  RESULTS
  The tooth length measured by CBCT was smaller than that measured with the vernier caliper. Significant differences were found in six areas, except the maxillary and mandibular premolar areas. With the increase of mesial-distal inclination or buccolingual torque angle, the difference between tooth length measured by CBCT and that measured with vernier caliper increased. The correlation between buccolingual torque angle (∠X1) and the coronal view of CBCT radiology tooth length (Spearmen index was 7.00, P < 0.001), and the correlation between mesial-distal inclination and the coronal view of CBCT radiology tooth length (Spearmen index was 0.624, P < 0.001) were found.
  
  
  CONCLUSIONS
  The tooth length measured by CBCT was smaller than that measured with vernier caliper.
authors: Department of Orthodontics, Hospital of Stomatology, Lanzhou University, Lanzhou 730000, China.
authors: Yi-qiang
authors: YQ
authors: Yang
authors: Department of Orthodontics, Hospital of Stomatology, Lanzhou University, Lanzhou 730000, China.
authors: Zhen-lin
authors: ZL
authors: Mi
authors: Department of Orthodontics, Hospital of Stomatology, Lanzhou University, Lanzhou 730000, China. Email: gezhl@lzu.edu.cn.
authors: Zhen-lin
authors: ZL
authors: Ge
mesh_terms: D000328:Adult; D001641:Bicuspid / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009811:Odontometry / Q000379:methods*; D011861:Radiography, Dental; D011897:Random Allocation; D014070:Tooth / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*