IOTN is not used for which malocclusion?
(A) Open bite (B) CLP (C) Bimaxillary protrusion (D) Crowding
(C) Index of Orthognathic Functional Treatment Need 
This index applies to those malocclusions that are not amenable to orthodontic treatment alone, due to skeletal deformity, and will ordinarily apply to those patients who will have completed facial growth prior to surgery (commonly 18 years of age and older) It relates only to the functional need for treatment and should be used in combination with appropriate psychological and other clinical indicators.