A comparative study of five indices in malocclusion for evaluating treatment needs

Abstract

The purpose of this study was to investigate the utility of five indices of malocclusion (NMT, MI, HLDI, OFI and DI) for evaluating the necessity of orthodontic treatment. One dentist scored malocclusion in 40 females (Age: 18-23). Then, another orthodontist assessed the treatment needs for malocclusion on the same subjects. We compared each score with the assessment by the orthodontist and determined the screening level score of the treatment needs for malocclusion. The sensitivity and specificity were calculated for 5 indices respectively. The selection using MI (screening level score: 12) resembled mostly the assessment by the orthodontist, followed by NMT (screening level score: 8) and DI (screening level score: 8). But the time required to score using MI was longer than using DI, and the reproducibility of NMT was inferior to DI. The subjects in this study had a high frequency of crowding (22.5%), and DI was highly correlated to the arch length discrepancy (r = -0.898). From these results, it was suggested that DI was a suitable index for evaluating the treatment needs for malocclusion, particularly crowding.