IADR Abstract Archives

Graduate Orthodontic Cases Evaluated with the ABO Discrepancy Index: 2000-2004

Objectives: The American Board of Orthodontics developed the Discrepancy Index to assign difficulty values for Board patients. Residents must treat a certain number of cases with varying degrees of difficulty. The Discrepancy Index (DI) indicates the difficulty of a patient by quantifying each aspect of malocclusion with a point value, the sum of which is the overall DI. The objective of this study was to compare the pretreatment Discrepancy Index scores with length of treatment time.

Methods: The DI score quantifies problems that are common in an orthodontic diagnosis: overjet, overbite, anterior openbite, posterior openbite, crowding, occlusion, lingual/buccal posterior crossbite, angle of ANB, IMPA, and angle of SN-GoGn. Higher DI scores are believed to be indicative of greater difficulty in treatment. A longitudinal study of 478 cases from 2000-2004 were evaluated, and length of treatment (months) was compared to groups of DI scores.

Results: Cases with DI <10 (47 cases; 10%) were completed in an average of 21 months. Cases with DI 10-20 (227 cases; 47.5%) had a mean treatment time of 23.2 months. Cases with DI >20 (204 cases; 42.7%) were completed in an average of 25.2 months. The cephalometric section of the DI was the greatest source of points at 25% of the overall score, followed by crowding (15%), overjet (12%) and overbite (11%) as the other significant contributing categories.

Conclusions: Length of treatment time was shown to increase with higher DI scores. If length of treatment is determined by difficulty, these results help to validate the DI score as an index of complexity and difficulty. Since cases with DI >20 required an average of 25.2 months to complete, these findings may have important implications for the optimal duration of graduate orthodontic programs. Supported by the J. Dean Robertson Society.


IADR/AADR/CADR General Session
2009 IADR/AADR/CADR General Session (Miami, Florida)
Miami, Florida
2009
2807
Craniofacial Biology
  • Hoybjerg, Adam  ( University of Oklahoma, Edmond, OK, USA )
  • Currier, G. Frans  ( University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA )
    • Poster Session
    Sarnat Competition, Speech, Cephalometry
    04/03/2009