The relationship between pre and post treatment soft tissue profile and American Board of Orthodontics objective grading system

Abstract

Introduction: The American Board of Orthodontics Objective Grading System (ABO OGS) is an index used to determine the improvement achieved by orthodontic treatment in cases submitted for Phase III of board-certification exam. This index can also be used by clinicians for self-evaluation of the finesse achieved in their cases. This study aims to determine the correlation between profile improvement and ABO OGS score.
Material and Methods: Total of 30 cases with ABO Discrepancy Index 16-24 were included in the study. The ABO OGS score was determined for these cases. Pre- and post-treatment Cephalograms were traced and the tracings were scanned and filled to produce silhouettes using Adobe Photoshop 7.0. An album was made with pretreatment silhouettes on the left side and post treatment on the right side. The improvement achieved in profile for each case was evaluated by 13 orthodontists and 31 orthodontic patients on a visual analogue scale (VAS). Mann Whitney U test was used to compare the scoring by orthodontist and orthodontic patients, and Spearman correlation test assessed the relationship between ABO OGS and VAS score.
Results: In 17 cases no significant difference existed between orthodontist and orthodontic patients, whereas in 13 cases the difference between the scorers was significant (p ≤ 0.05). ABO OGS and VAS score were significantly correlated in only one case (rs =-0.758; p=0.029) for scoring by orthodontist and in three cases for scoring by orthodontic patients (rs = -0.802, -0.902, 0.776 and p=0.017, 0.002, 0.024 respectively).
Conclusions: Significant correlation was not found between ABO OGS score and improvement in soft tissue profile, therefore this study recommends revision of ABO OGS criterion for inclusion of soft tissue parameters to allow a more realistic evaluation of the success of orthodontic treatment.