Relationship between index of complexity, outcome and need, dental aesthetic index, peer assessment rating index, and American Board of Orthodontics objective grading system.

Introduction: The objectives of this study were to examine the relationships among 4 indexes that are used to score orthodontic treatment need and outcome, and to determine whether 1 index could replace the other 3. The index of complexity, outcome, and need (ICON), the dental aesthetic index (DAI), the peer assessment rating (PAR) index, and the American Board of Orthodontics objective grading system (ABO-OGS) were studied. The use of the ICON is desirable because it is faster to use than separate indexes for assessing different treatment facets.

Methods: One hundred pretreatment and posttreatment study models were randomly selected from an accredited graduate orthodontic clinic at University of Illinois at Chicago, Chicago, Ill. The sample was assessed by using the PAR index, the DAI, the ABO-OGS, and the ICON. The data were analyzed descriptively and the relationships evaluated by using the Spearman rank order correlation coefficient.

Results: The study showed a significant correlation between the DAI and the ICON with respect to treatment need (r = .5523, P <.001). The PAR index and the ABO-OGS had significant correlations with the ICON for treatment outcome (pretreatment PAR vs ICON, r = .6840, P <.001; posttreatment PAR vs ICON, r = .3466, P <.001; ABO-OGS vs ICON, r = .2654, P <.01).

Conclusions: The ICON can be used in place of the PAR and the ABO-OGS for assessing treatment outcome and in place of the DAI for assessing treatment need.