Comparison of prospectively and retrospectively selected American Board of Orthodontics cases

In this study, we compared the pretreatment conditions, treatment characteristics, and orthodontic outcomes of 3 groups of subjects selected for the American Board of Orthodontics (ABO) phase III clinical examination. One group was selected retrospectively by graduating residents just before their graduation. The 2 prospective groups were treated at separate institutions. The students at 1 institution were not aware that these patients would be potential ABO cases (prospective, blinded), but the students at the second institution were aware that these subjects would serve as their pool of potential patients for the ABO examination (prospective, unblinded). In addition to comparing the 3 groups, all cases were categorized as passing or failing based on their total objective grading system (ABO-OGS) score to assess the ABO-OGS criteria that were the most challenging to meet.

Chart histories and orthodontic dental casts (pretreatment and posttreatment) were collected for 133 subjects. Information regarding demographics, initial malocclusion type, treatment modality, treatment duration, appointment frequency, and missed appointments were collected from chart histories. Pretreatment dental casts were evaluated by using the discrepancy index; the index of complexity, outcome, and need; and the peer assessment rating. Posttreatment dental casts were evaluated with the peer assessment rating and the ABO-OGS.

The only significant pretreatment characteristic with predictive power for favorable orthodontic outcome was Angle Class I (3.1 odds ratio for passing the ABO-OGS) compared with the Class II subjects. The prospective unblinded group received more extraction and headgear therapy than did the other groups. The retrospective group had significantly lower total ABO-OGS posttreatment scores and a higher passing rate compared with the prospective groups.

Angle Class I malocclusions appear to have some advantage for achieving passing ABO-OGS scores, as does the retrospective selection of cases. Successful board certification appears difficult to accomplish based on a prospective model for orthodontic graduate residents. New graduate candidates might be at a disadvantage compared with traditional candidates because they often cannot take advantage of the posttreatment settling phase. Alignment, marginal ridges, and occlusal contacts appear to be where most points are deducted in the evaluation of ABO-OGS certification cases.