[A pilot study on the accuracy of digital model reconstructed by cone beam CT]

To study the feasibility of digital model produced by cone beam CT.

Ten patients seeking orthodontic treatment with congested lower incisors were enrolled in this study. Plaster models of the lower arch were made using routing method. Digital model was reconstructed from these plaster models by NewTom 3G cone beam CT with 6 inch model. Linear measurements including right first premolar width, arch width, arch length, right first incisor width, all incisors and canines width, were done on the lower arch on plaster models with calipers. The same measurements on digital model were made using software Simplant Pro11.04. Linear measurements were repeated one week later on both plaster and digital model. Paired t test was used to determine the difference between the linear measurements on both models. The absolute measurements errors of two models were compared using paired t test. All statistical analysis was performed using SPSS13.0 software package.

The linear measurements of the digital model slightly underestimated the real plaster model, but no significant difference of the linear measurements was seen between the plaster model and the digital model. The value of all of the lower incisors and canines width of plaster models was significantly higher than that of digital model. Mean absolute difference of different measurement of digital model was not significant from that of plaster model.

Digital model using CBCT is feasible for the linear measurement and storage.