Diagnostic capability of Little irregularity index to estimate arch length discrepancy
Egyptian Orthodontic Journal
Objective: Objective: Objective: Objective: The aim of the present study is to evaluate the diagnostic capability of Little irregularity index (LII) to estimate arch length deficiency (ALD) in a dental arch. Material and methods: Five hundred dental casts were selected from 1000 study models from the patients (12-14 years old) attending the Dental Clinic of Orthodontic, in Tanta University. The casts were categorized according to sex, degree of crowding and upper or lower. In order to classify
... order to classify cases according to degree of crowding ALD was calculated as the difference between available and required space in each dental arch anterior to the first permanent molars. LII was calculated on each cast by measuring the linear displacement between the six anterior teeth, and was contrasted with the dichotomized ALD. The receiver operator characteristic curve (ROC) was applied to suggest optimal cut-off points for LII to estimate ALD. Results: Results: Results: Results: High correlation was observed between ALD and LII (-0.91, P<0.0001). According to ROC curve, LII of >0, >3.5, >6mm were optimized cut-off points to estimate minimum, moderate and severe crowding respectively. Regarding the analysis of ROC Student for master degree in orthodontics. Egyptian Orthodontic Journal 16 Volume 38 -December 2010 curve for minimum crowding cases, LII was found to have the highest diagnostic capability of >0mm or minimum crowding with sensitivity 1.00 and specificity 1.00, then the moderate crowding with sensitivity 96.45 and specificity 97.96 and severe crowding with of sensitivity 91.95 and specificity 84.05. Conclusion Conclusion Conclusion Conclusion: The results of ROC provided useful insights of the potentiality of LII to estimate negative ALD of the dental arch.