Comparison of Linear Measurments Obtained from CBCT and Dental Impressions

Objective:

To determine if measurements obtained from digital models from cone beam computed tomography (CBCT) images were comparable to the traditional method of digital study models by impressions.

Method:

Digital models of 26 subjects were used. InVivoDental (Anatomage, San Jose, Calif) software was used to analyze CBCT scans taken by a Kodak 9500 CBCT Imaging Device with a voxel resolution of 0.125 mm. OrthoCAD (Cadent, Fairview, NJ) software was used to analyze impression scans of patients at the initial stage of orthodontic treatment. Impressions were taken using alginate and were mailed to OrthoCAD for digital conversion. The scans were then electronically returned in digital format for analysis. A total of 14 different linear measurements (7 per arch) were taken.

Result:

The mean of the absolute differences of the 7 measurements of in arch were 1.85±1.58 and 1.91±1.62 for the maxillary and mandibular digital models respectively. A paired t-test performed on the linear arch measurements showed no statistical significance between measurements obtained from the two types of digital models (Pvalue>0.05).

Conclusion:

CBCT digital models are as accurate as OrthoCAD digital models in making linear measurements for overjet, overbite, and crowding measurements.  This study suggests that these records meet the accuracy requirements to be used for diagnostic and treatment planning purposes.