[The reliability of dento-maxillary models created by cone-beam CT and rapid prototyping:a comparative study]

To analyze the reliability of the dento-maxillary models created by cone-beam CT and rapid prototyping (RP).

Plaster models were obtained from 20 orthodontic patients who had been scanned by cone-beam CT and 3-D models were formed after the calculation and reconstruction of software. Then, computerized composite models (RP models) were produced by rapid prototyping technique. The crown widths, dental arch widths and dental arch lengths on each plaster model, 3-D model and RP model were measured, followed by statistical analysis with SPSS17.0 software package.

For crown widths, dental arch lengths and crowding, there were significant differences(P<0.05) among the 3 models, but the dental arch widths were on the contrary. Measurements on 3-D models were significantly smaller than those on other two models(P<0.05). Compared with 3-D models, RP models had more numbers which were not significantly different from those on plaster models(P>0.05). The regression coefficient among three models were significantly different(P<0.01), ranging from 0.8 to 0.9. But between RP and plaster models was bigger than that between 3-D and plaster models.

There is high consistency within 3 models, while some differences were accepted in clinic. Therefore, it is possible to substitute 3-D and RP models for plaster models in order to save storage space and improve efficiency.