3: Occlusal indices

Chapter 3

Occlusal indices

The demand for orthodontic treatment has grown steadily over the years. The public’s awareness of the condition of their teeth and smile has driven the desire to have ‘straight teeth’ and a confident smile.

As a result of this, more and more patients are asking to be referred to an orthodontist for treatment.

The Index of Orthodontic Treatment Need (IOTN) was devised as a scale for standardising measurement, by including:

  • degree of severity
  • aesthetics

The increasing demand for treatment may mean that not all patients that would like treatment are eligible to receive it under a third party funded system, e.g. the National Health Service (NHS).

Where there are finite resources, there has to be a balance between what is wanted and what is needed. This means a prioritising of treatment and takes into account:

  • the entry levels for treatment
  • the availability of funds and clinician
  • the hierarchy of treatment providers

To assess the needs of a patient using a standard set of criteria means that each orthodontic assessment arrives at a similar conclusion.

As such, it needs to have several functions.

  • It needs to be an assessment that uses a series of ‘benchmark criteria’
  • It needs to measure the severity of the presenting conditions
  • It needs to assess whether by treating their orthodontic problem the patient would have significant benefits

IOTN has two components.


This is to measure and quantify the severity of the malocclusion in the categories, which range from IOTN 5, which is the most severe, to IOTN 1, which measures no significant deviation from normal (Figure 3.1).

In any malocclusion, the one presenting the worst deviation from the norm is measured.

These may include:

  • supernumerary teeth
  • impacted teeth
  • a reverseoverjet
  • displacement of tee/>
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Jan 2, 2015 | Posted by in Orthodontics | Comments Off on 3: Occlusal indices
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