Relationship between Two Indices in the Assessment of Orthodontic Treatment Complexity and Need

Objective: To determine the relationship between the Index of Complexity, Outcome and Need (ICON) and Dental Aesthetic Index (DAI) in the assessment of orthodontic treatment complexity and need.
Methods: A cross-sectional study was carried out. Pre-treatment dental casts of 150 consecutive patients from Lagos, Nigeria were assessed using the ICON and the DAI criteria. One investigator assessed all the models. In addition to descriptive statistics, the relationship between the ICON and DAI was examined by using non-parametric correlations (Spearman Rank Order and Pearson’s Product Moment Correlation Coefficient.
Results: Forty-five (30%) of the subjects were classified by both ICON and DAI as having no treatment need. Of the 25(16.7%) that ICON classified as having difficult / very difficult complexity grades, 19(12.7%) of them were classified as having handicapping malocclusions by DAI standards. There was a significant correlation between DAI and ICON with regard to treatment need (p = 0.000). Also, there was a very statistically significant correlation between the ICON complexity grades and the DAI severity levels of malocclusion (p = 0.000). In general, both indices exhibited highly significant positive correlations (r = 0.600; p = 0.000).
Conclusion: Both indices were generally in agreement on both aspects of orthodontic provision assessed. This suggests that both ICON and DAI can be used in the assessment of these facets of orthodontic care.