The validity of in vivo tooth volume determinations from cone-beam computed tomography.
OBJECTIVE
To determine the accuracy of volumetric analysis of teeth in vivo using cone-beam computed tomography (CBCT).


METHODS
The physical volume (Vw) of 24 bicuspids extracted for orthodontic purposes (16 were imaged with the I-CAT and 8 with the CB MercuRay) were determined using the water displacement technique. Corresponding pretreatment CBCT image data were uploaded into Amira 4.0 for segmentation and radiographic volume (Va). All measurements were performed twice by two observers. The statistical difference between Vw and Va was assessed using a paired t-test. The intraobserver and interobserver reliability were determined by calculating Pearson correlation coefficients and intraclass correlation coefficients.


RESULTS
The overall mean Vw of teeth specimens was 0.553 +/- 0.082 cm3, while the overall mean Va was 0.548 +/- 0.079 cm3 (0.529 +/- 0.078 cm3 for observer 1 and 0.567 +/- 0.085 cm3 for observer 2). There were statistically significant differences between Va and Vw (P < .05). Between observer 1 and observer 2, Va measurements were statistically significantly different (P < .05). The interobserver and intraobserver correlation coefficient for Vw was high. Lastly, surface smoothing reduced the volume by 3% to 12%.


CONCLUSIONS
In vivo determination of tooth volumes from CBCT data is feasible. The measurements slightly deviate from the physical volumes within -4% to 7%. Smoothing operations reduce volume measurements. Currently, no requirements for accuracy of volumetric determinations of tooth volume have been established.
Liu
Yi
Y
Department of Orthodontics, Peking University School of Stomatology, Beijing, China.
Olszewski
Raphael
R
Alexandroni
Emanuel Stefan
ES
Enciso
Reyes
R
Xu
Tianmin
T
Mah
James K
JK
D000293:Adolescent; D000328:Adult; D001641:Bicuspid / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D054893:Cone-Beam Computed Tomography / Q000379:methods* / Q000706:statistics & numerical data; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D015588:Observer Variation; D009811:Odontometry / Q000379:methods / Q000706:statistics & numerical data; D009929:Organ Size; D010865:Pilot Projects; D014584:User-Computer Interface; D055815:Young Adult