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IOTN - What problems qualify for NHS orthodontic Treatment?


The 'need' for treatment is graded upon a broadly agreed national clinical convention using the Index of Orthodontic Treatment Need (IOTN). Problems with a more severe grading on this scale are likely to derive a significant dental health benefit from orthodontic treatment. The IOTN has two parts:

  1. Dental Health Component (DHC, Grade 1-5) and
  2. Aesthetic Component (AC, Grade 1-10)


The Thames Valley Area Team, following guidelines from the Department of Health, has set the following criteria for the purpose of rationing NHS orthodontic treatment to those most likely to gain a dental health benefit; this may varied be in the future:

  • Rule 1 - There is either GREAT need (DHC Grade 5) or MODERATE need (DHC Grade 4) for treatment.
  • Rule 2 - There is BORDERLINE need (DHC Grade 3) for treatment and the appearance of the teeth is grade 6 or above on the Aesthetic Scale.

Listed below are some of the common problems that qualify - only for the technically minded!

Qualifying Problems

  1. Missing teeth; including developmentally missing teeth (also known as hypodontia), ectopic and impacted teeth (excluding wisdom teeth)
  2. Overjet (increased horizontal overlap between upper and lower front teeth - protrusion) and reverse overjets (underbite); overjets usually need to greater than 6 mm and reverse overjets greater than 3.5 mm
  3. Cross-bites with jaw displacement on closing; displacement greater than 2 mm
  4. Crowding of teeth; greater than 4 mm displacement between adjacent teeth. Less severe displacement of teeth 2-4 mm) may qualify under 'Rule 2' (see above) where the crowding is noticeable in the alignment of the upper front teeth
  5. Overbite(increased vertical overlap between upper and lower front teeth); causing damage to the gums

For further inforamtion visit the webpage about IOTN at the British Orthodontic Society.