Reliability of High Resolution CBCT Imaging for tooth size measurements

Objectives:

Cone Beam Computed Tomography (CBCT) units produce isotropic and isometric images. Tooth Measurements have been performed for impacted teeth, canal length, crown width and crown to root ratio estimation. The objective of this study was to investigate reliability of CBCT in tooth measurements.

Methods:

Twenty four patients participating in a periodontal regeneration study were previously imaged by high resolution CBCT unit (3D Accuitomo) for follow-up purposes. Imaging was performed twice with 30 days interval. Two sound teeth in every CBCT volume were chosen for the sample. Values obtained for tooth length were between the apex of the tooth and middle of the incisal edge in incisors or tip of the cusps in posterior teeth. Values obtained for tooth width represent the maximum diameter between mesial and distal contact points of each tooth. Measurements were performed on coronal views for anterior teeth and on sagittal views for posterior teeth using I-Dixel-3DX software. Measurement error was calculated and described as the standard deviation of the replicate measurements.

Results:

The average tooth length in this study was 19.8 mm with range of 16.8–23.3 mm. There was no difference in the mean of tooth length between time points. The calculated measurement error was 0.41 mm with error range of 0–0.82 mm. The average tooth width was 7.4 mm with range of 5.3–11.1 mm. There was no difference in the mean of tooth width between time points. The calculated measurement error was 0.31 mm with error range of 0.01–0.72 mm.

Conclusions:

CBCT imaging performed in high resolution mode is a reliable tool for tooth size measurements with same magnitude of error as plaster method. With crowded dentition, impacted teeth and indefinite contact points on plaster models, CBCT has the potential of proving to be a reliable method.