IOTN as an assessment of patient eligibility for consultant orthodontic care

When I started as a single-handed consultant in 2001, the existing service demands within the department meant that I had no option but to implement prioritisation of treatment to only those patients who specifically required consultant-level care. In other departments, thresholds for case acceptance may have evolved more gradually due to changes in local specialist practice provision, manpower and caseloads. However, regardless of how many of these changes have come about, geographical variations in orthodontic provision (a 'postcode lottery') now exist within the UK. Given recent changes in UK health economics and NHS orthodontic commissioning, it is now clear that the distinctions, which may have pragmatically been drawn between primary and secondary care provision at local levels, need to be more clearly defined on a national (or at least England-wide) scale.

Consultant members of the British Orthodontic Society will be aware that the society's Consultant Orthodontist Group (COG) is reviewing the applicability of the Index of Orthodontic Treatment Need (IOTN)1 in its current format, to the consultant orthodontic service. At present, the NHS commissioning of orthodontic treatment from secondary care providers allows for IOTN grades 4 and 5 to be treated. However, it does not help to differentiate treatment eligibility according to the differing skills possessed by primary care providers (specialist orthodontists and general dentists) and consultants working in secondary care. In addition, whilst consultants' caseloads meet these IOTN requirements, with a high volume of orthognathic and dentoalveolar surgical work, inter-disciplinary restorative, and cleft lip/palate cases, contractual arrangements consider neither treatment complexity nor a consultant-specific standardisation of caseload selection. Therefore, it is questionable whether the standard version of the IOTN is the most suitable tool for both consultants and commissioners in determining the ideal qualifications, expertise and clinical facilities required for the treatment of severe malocclusions. Arguably, both patients and the UK taxpayer would benefit from more formal, customised and standardised guidance on which patients and types of dentofacial anomalies would benefit most from the consultant service and its limited resources. It is also timely for this issue to be addressed from a training perspective, since it should help both clinicians and commissioners to more easily comprehend and identify the clinical caseload required for the post-specialisation training leading to the consultant level.

Whilst IOTN is an excellent tool when used to grade many common malocclusion traits, it appears to be skewed in favour of class II discrepancies and specifically against class III and anterior open bite (AOB) problems. Both malocclusions can cause patients difficulty with incising food, yet such functional problems, or the traumatic loading of class III incisors, are difficult to quantify and not featured in the IOTN. This may have arisen in part because IOTN was based on evidence available in the 1980s, such as the risks of trauma to prominent incisor teeth, but before quality of life (QoL) research had been applied to orthodontics. In addition, the IOTN does not account for facial features, deformity and soft tissues, as exemplified by compensated class III cases where the incisor inclination is already at the maximum clinical limit; obstructive sleep apnoea patients; and those with excess vertical facial growth, disproportionate display of the maxillary dentoalveolar complex and lip incompetence.

Furthermore, there is not necessarily a correlation between the IOTN grade of a presenting malocclusion and the functional/QoL improvements from subsequent treatment. For example, when asked about the effects of treatment I cannot imagine any patient with a modest class II malocclusion (for example, 7 mm overjet: IOTN 4a) citing a profound change in their quality of life after orthodontic treatment. In contrast, multiple patients who have presented with class III and AOB problems, which also score IOTN 4, have made post-treatment comments to me such as ‘I now feel human when I eat’. This illustrates the need to somehow apply Patient Reported Outcome Measures (PROMs) to case selection, and interestingly these have already been proposed as future outcome indicators for orthognathic cases.

Finally, it is worth highlighting that the selection of cases for consultant care should not be dictated by the treatment modality. Thus, a patient with a severe class II malocclusion and/or traumatic overbite should not be offered treatment if their selected plan involves orthognathic surgery but declined treatment if the plan involves a non-surgical solution, typically involving complex orthodontic biomechanics. Given these issues, I look forward to the publication of a consultant-specific version of IOTN which I hope will clarify case acceptance criteria for all parties involved: patients, commissioners, dentists, primary care orthodontists and consultants.