Use of the Objective Grading System of the American Board of Orthodontics to evaluate treatment at the Orthodontic Graduate Program Clinic, University of Puerto Rico, 2007-2008.

Objective: The Objective Grading System (OGS) was introduced in 1999 by the American Board of Orthodontics (ABO) as an instrument to reduce subjectivity when evaluating cases submitted to the ABO for examination. The objectives of this study were (1) to employ the OGS to determine the percentage of treated and completed cases from the University of Puerto Rico's (UPR) Orthodontic Graduate Program Clinic that would have earned a passing OGS score (according to the ABO standards) and (2) to assess the contribution of various patient characteristics and factors to this score.

Methods: A total of 64 cases completed during 2007 and 2008 met the inclusion criteria and were evaluated by a calibrated examiner using the OGS. Logistic regression and multiple regression analyses were performed to assess the association between the explanatory variables and the overall OGS score.

Results: Of the cases evaluated, 18.8% received a passing OGS score of <20, 34.4% received a borderline score of 20-30, and 46.9% received a failing score of >30. The mean OGS score was 32.17 +/- 13.03 points, similar to the mean OGS score of 34.36 +/- 10.39 reported in 2004 by a similar study.

Conclusion: This study demonstrate that 53% of the completed cases at the university clinic obtained a potential passing score as per the ABO (OGS <30 points). Multiple and logistic regression analyses could neither explain the relationship between the explanatory variables and the OGS scores nor predict the probability of a particular case's passing when all variables were considered.