RESUMO
The purpose of this study was to determine whether cone beam digital models are as accurate as OrthoCAD (Cadent, Inc, Carlstadt, NJ) digital models for the purposes of orthodontic diagnosis and treatment planning. Digital records of 30 subjects were retrospectively reviewed, and the digital models were obtained as OrthoCAD and InVivoDental (San Jose, CA) digital models. Seven parameters indicating linear measurements from predetermined landmarks were measured and analyzed. The analysis of variance and Bland and Altman Analysis were used to compare and evaluate measurements made from the study models generated from cone beam computed tomography (CBCT) and InVivoDental software. The mean difference between the maxillary InVivoDental models and the maxillary OrthoCAD models ranged from -0.57 to 0.44 mm. The analysis of variance for repeated measures (P < 0.001) was applied to all data obtained from the CBCT and OrthoCAD models. The results indicated a mean score of 35.12 and 35.12 mm, respectively. The mean difference of all values was -7.93 × 10-3 mm. The range of these values at the 95% confidence interval was -0.14 and 0.12 mm for the lower and upper limits, respectively. The results were not statistically significant for both groups. The Bland and Altman analysis was also applied to the data. In the maxilla, the results indicated that the mean difference between InVivoDental and OrthoCAD was -0.01 ± 1.24 mm. The range of the analysis indicated a spread of -2.40 mm and +2.40 mm. In the mandible, the results indicated that the mean difference between InVivoDental and OrthoCAD was -0.01 ± 1.21 mm. The range of the analysis indicated a spread of -2.36 mm and +2.37 mm. The results showed that the linear measurements obtained from CBCT image casts indicated a good level of accuracy when compared with OrthoCAD models. The accuracy was considered adequate for initial diagnosis and treatment planning in orthodontics.
RESUMO
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. MATERIALS AND METHODS: Digital models of 30 subjects were used. InVivoDental (Anatomage, San Jose, Calif) software was used to analyze CBCT scans taken by a Galileos cone beam scanner (Sirona, Charlotte, NC) with a field of view of 15 x 15 x 15 cm(3) and a voxel resolution of 0.125 mm. OrthoCAD (Cadent, Fairview, NJ) software was used to analyze impression scans of patients at different stages 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. RESULTS: The maxillary mean scores for the Little's Index were 9.65 mm for digital models and 8.87 mm for InVivoDental models, respectively. The mandibular mean scores for the Little's Index were 6.41 mm for digital models and 6.27 mm for InVivoDental models, respectively. The mean overjet measurements were 3.32 mm for digital models and 3.52 mm for InVivoDental models, respectively. The overbite measurements were 2.29 mm for digital models and 2.26 mm for InVivoDental models, respectively. The paired t-test showed no statistical significance between the differences in all measurements. CONCLUSIONS: CBCT digital models are as accurate as OrthoCAD digital models in making linear measurements for overjet, overbite, and crowding measurements.