This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Index for orthodontic treatment needs is/are: 
Select and explain. 
A. SCAN index, B. ICON index, C. DAI index, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: SCAN index is the synonym for Index for Orthodontic Treatment Needs (IOTN). IOTN index was developed by BROOK and SHAW to link dentofacial variation to perceive esthetic impairment.
Key Concept:
The other Orthodontic treatment need indices are:

Handicapping Labio-lingual Deviation Index (HLD) (Draker)
Dental Aesthetic Index (DAI) (Cons et al)
Index of Complexity, Outcome and Need (ICON) (Daniels & Richmond)