A total of 160 patients who completed their orthodontic treatment were included in the study. The participants were randomly selected from patients who completed their orthodontic procedures in Kunming Medical University Affiliated Stomatological Hospital during the period of 2015 to 2019. The retrospective completed cases were examined in accordance with the Andrews' six elements and ABO measuring scales. Scores were assigned to each tooth in each category. All the measurement items in both evaluation criteria, the composite category score, and the total score were calculated. The passing and potential passing rates of the completed cases were compared with two measuring scales via the Chi-square test.

The passing rate for the evaluation of cases by using the Andrews' six elements measuring scale was 83.8%, and that for the evaluation of cases by using the ABO measuring scale was 86.3%. The differences in achieving the standard between the cases of Andrews' six elements and ABO-OGS via the Chi-square test were statistically insignificant (P>0.05). The mean Andrews' six elements score for the completed cases: the category of the anteroposterior change in position of the incisors contributed the most, whereas the core discrepancy presented the least percentage in total scores. In ABO-OGS, alignment and marginal ridges contributed the most, whereas interproximal contacts exhibited the least percentage in total scores.

The performance of Andrews' six elements was comparable with that of ABO-OGS in assessing the treatment outcome of patients who completed their orthodontic treatment. Andrews' six elements can be used as a new system for assessing the treatment outcome of patients who completed their orthodontic treatment. It demonstrated particular advantage in controlling facial profile, and had just completed material of patients who completed their orthodontic treatment it can measure. The Andrews' six elements measuring scale is convenient to disseminate and use.