Construction of orthodontic setup models on a computer.
BACKGROUND
Orthodontic setup models are usually limited to the display of teeth, with no information about the roots. The purpose of this article is to present a method for visualizing the tooth roots in setup models by integrating information from cone-beam computed tomography and a laser scanner. The reproducibility of the integration was evaluated.


METHODS
The records of 5 patients were used in this study. Three-dimensional digital models were generated from the dental casts. Tooth models were generated from the cone-beam computed tomography slices. The 3-dimensional models were superimposed on the crowns of the teeth in the tooth models and integrated. The integrated 3-dimensional tooth model and 3-dimensional setup model were registered. The reproducibility of the integration was evaluated for each tooth. Unpaired Student t tests were performed on the data between the anterior and posterior teeth, and between the right and left teeth.


RESULTS
The discrepancy among the integrated 3-dimensional models at the final positions after we used this technique was 0.025 ± 0.007 mm. There was a significant difference in the distance between the anterior and posterior teeth (P <0.05). However, the average distances between the anterior and posterior teeth were small: 0.023 ± 0.007 and 0.028 ± 0.007 mm, respectively. No significant difference was found between the right and left teeth (P = 0.831).


CONCLUSIONS
The methods presented in this study provide a reproducible visualization of tooth roots in virtual setup models by registering accurate crown models to cone-beam computed tomography scans.
Department of Oral Biology and Engineering, Division of Oral Health Sciences, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Takuya
T
Kihara
Kotaro
K
Tanimoto
Masahiko
M
Michida
Yuki
Y
Yoshimi
Toshikazu
T
Nagasaki
Takeshi
T
Murayama
Kazuo
K
Tanne
Hiroki
H
Nikawa
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography; D003724:Dental Arch / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D003765:Models, Dental; D009971:Orthodontics, Corrective; D010347:Patient Care Planning; D015203:Reproducibility of Results; D014092:Tooth Root / Q000000981:diagnostic imaging*; D014584:User-Computer Interface; D055815:Young Adult