Evaluation of a software program for applying the American Board of Orthodontics objective grading system to digital casts.

INTRODUCTION

The American Board of Orthodontics' objective grading system (ABO OGS) is currently the gold standard for evaluating plaster casts of completed orthodontic cases.

METHODS

Thirty-six cases of finished orthodontic casts in plaster and digital form were scored by using 2 methods: an electronic version of the ABO OGS designed to be used with digital casts (OrthoCAD, Cadent, Fairview, NJ) and the ABO gauge designed to be used with plaster casts. The 2 scoring methods were compared using descriptive analysis (range, absolute mean difference, and standard deviation), the Spearman rank correlation coefficient, and the Wilcoxon rank sum test.

RESULTS

Intraexaminer reliability was high for both the plaster and the digital casts (r = 0.998). A statistically significant difference (P <.001) was found when comparing the total ABO scores from the plaster and digital casts. The scores from digital casts exceeded the scores from plaster casts by an average of 9.0 +/- 5.4 points. This difference was due to statistically significant differences in 3 ABO OGS components: alignment, occlusal contact, and overjet.

CONCLUSIONS

The results indicate that this computer version of the ABO OGS cannot be used as a substitute for manual grading with the ABO ruler.