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Document What is IOTN?

Index of Orthodontic Treatment Needed (IOTN) is a scale designed to measure the orthodontic need of a patient. It has two components:

  • The Dental Health Component (DHC)

  • The Aesthetic Component (AC)

The Dental Health Component (DHC) scale (1 to 5):

1 = no need

2 = little need

3 = borderline need

4 = need

5 = very great need

The Aesthetic Component (AC) scale (1 to 10):

1 to 4 = little or no need

5 to 7 = borderline need

8 to 10 = great need

NHS funded orthodontic treatment is normally restricted to individuals with a DHC of 5, 4 or 3 with an AC of 6 or more.

If the DHC value is 3, the AC must also be recorded in box 5 of Part 5 on the FP17O / FP17OW.

In transfer cases it's the original IOTN that determines a patient’s eligibility for NHS funded orthodontic treatment and therefore box 6 (IOTN not applicable) should be crossed in Part 5 on the FP17O / FP17OW.

Guidance for completing the FP17O is available on the NHS Dental Services website.

IOTN, Index, scale, component, aesthetic,