The development of the index of complexity, outcome and need (ICON).

AbstractThis paper is based on the winning submission for the 1998 Chapman prize awarded by the British Orthodontic Society for an essay on a subject promoting the interests of orthodontics. The aim of the investigation is to develop a single index for assessing treatment inputs and outcomes. An international panel of 97 orthodontists gave subjective judgements on the need for treatment, treatment complexity, treatment improvement, and acceptability on a diverse sample of 240 initial and 98 treated study models. The occlusal traits in the study models were scored according to a defined numerical protocol. Five highly predictive occlusal traits were identified (IOTN Aesthetic Component, crossbite, upper arch crowding/ spacing, buccal segment antero-posterior relationships, and anterior vertical relationship) and then used to ‘predict’ the panellist's decisions using regression analysis. Cut-off values were determined for the dichotomous judgements by plotting specificity sensitivity and overall accuracy. T...