C

The Dental Health Component of the Index of Orthodontic Treatment Need (IOTN) assigns grades for open bite, cleft lip ± palate defects, and displacement/crowding, but traits such as bimaxillary dento-alveolar protrusion are not represented in its scoring system, so IOTN is not used for that malocclusion [de Mûelenaere et al., 1998, PMID 9760933].