A while ago I was talking about IOTN — the Index of Orthodontic Treatment Need — and I thought I’d go a little bit deeper into the topic today.
And that means we need to go back in time
Sweden, 1974
Saab stopped producing the Draken fighter aircraft, around about the time that it became the first Airfix model I built.
Sweden was also in the middle of changing its constitution. The new arrangements would make the role of recently crowned King Carl XVI Gustav even more ceremonial — so no invading Denmark unless it goes to a vote.
Olof Palme was Prime Minister. Twelve years later, Sweden's greatest heavy metal guitarist, Yngwie Malmsteen would dedicate his Trilogy album to Palme’s memory. Both men would probably have preferred circumstances in which that particular dedication wasn't necessary.
Also in music, Nina Persson of The Cardigans was born in 1974. So was Mikael Åkerfeldt, the guy from Opeth, and, biggest of the lot, ABBA won Eurovision with Waterloo.
But in the world of teeth, something even more important was happening.
Sten Linder-Aronson (no relation to Linda Ronstadt) produced an index of orthodontic problems which could be used by the Swedish public dental service to help decide which children should receive orthodontic treatment.
His work was published in 1974 in the Transactions of the European Orthodontic Society. If you want to find it more easily, it was subsequently reproduced in the European Journal of Orthodontics in 2007 (Vol 29 supplement i124-127).
England, 1989
Fast forward 15 years. The year begins with Kylie and Jason at Number 1 with Especially for You. Later in the year, Gerry Marsden will take Ferry Cross The Mersey to Number 1, though he probably would have preferred circumstances in which that hadn’t happened as it did. The Berlin Wall came down and the rest of the Iron Curtain with it. The first Wallace and Gromit film appeared. Rory McIlroy was born. (And back in Sweden, Ikea are experimenting with the prototype of FRAKTA, the Blue Ikea Bag)
And between London and Manchester, Peter Brook and Bill Shaw published The Development of an Index of Orthodontic Treatment Priority in the European Journal of Orthodontics (Vol 11, 309-320).
Their index had developed from the Swedish work and was designed to provide a more objective way of deciding which orthodontic problems should have priority for treatment, particularly in the public sector. Somewhere in the mix, “Priority” became “Need”.
Just as there is an urban myth that Bob Holness from Blockbusters played sax on Gerry Rafferty’s Baker Street, within the orthodontic specialty it’s occasionally mentioned that Professor Bill Shaw played bass guitar on Chirpy Chirpy Cheep Cheep by Middle of the Road.
Prof Shaw taught the orthodontist that taught me and so I was advised of this orthodontic-musical nugget at an early stage in my career.
Is it true….
When I heard this, the internet wasn’t really a thing so it wasn’t easy to check it out. I did have the Guinness Book of 500 Number 1 singles but Bill Shaw wasn’t mentioned in it. If Chirpy Chirpy Cheep Cheep hadn’t made Number 1 I would have no easy way of verifying or denying it.
Until the early 2000s.
When I worked as a HSE Orthodontist in Merlin Park Hospital, the local consultant (Niall McGuinness) organised an annual study day with an absolute top tier of speakers to come and talk to us. One year Bill Shaw did come to give a lecture and so I asked him about it. It made a change from impacted canines.
It turned out he hadn't played on the recording.
However, he did occasionally play bass with Middle of the Road because he was friendly with members of the band. If their regular bass player wasn't available, Bill would sometimes step in — and apparently the same thing happened in reverse with the band he played with.
History has its facts, and legend has its myths.
And when facts escape us…we have the spirit of the Index of Orthodontic Treatment Need.
Ireland, 2007
Now let's come back to Ireland.
For many years the HSE — and, before that, the Department of Health — used the 1985 orthodontic guidelines to decide which children should receive public orthodontic treatment and how cases should be prioritised.
The 1985 guidelines divided orthodontic problems into three broad categories.
Category A covered craniofacial and developmental defects, such as cleft lip and palate.
Category B covered orthodontic problems which could be considered detrimental to dental health or function.
Category C covered problems which were generally aesthetic, such as crowding.
The basic idea was straightforward: the system was intended to provide an objective way of prioritising children for publicly funded orthodontic treatment.
Category A cases were given the highest priority. Category C cases were generally outside the scope of public treatment, while Category B cases sat somewhere between the two, depending on their clinical circumstances and available resources. But there was some uncertainty about its boundaries and how different problems within Category B could be ranked and prioritised.
Then things changed.
In 2007, following a review by the HSE Orthodontic Review Group, the HSE moved from the 1985 guidelines to new eligibility criteria based on a modified version of IOTN. This would give a more objective and systematic way of working out the relative position of orthodontic problems.
And this was quite an important change.
The new system didn't just look at whether an orthodontic problem affected health or function. It also incorporated the aesthetic component of IOTN.
The Aesthetic Component is essentially a scale of photographs running from 1 to 10, with the higher numbers representing increasingly unattractive dental appearance.
And this is where things get interesting.
Under the new HSE guidelines, an IOTN Grade 4d case (which was defined as severe displacement of the contact points of teeth by more than 4mm) would be eligible for HSE treatment, but only where the Aesthetic Component was 8–10. These wouldn't have been treated under the previous guidelines.
So, in simple terms, the system could now treat certain significant crowding cases where the appearance of the teeth was also judged to be at the severe end of the scale.
The actual HSE proposal is still available, although the link isn't particularly easy to find:
(non-live link, you can try to copy and paste in a browser) https://hdl.handle.net/10147/44938
The relevant section is on page 21.
The HSE also undertook calibration of orthodontists so that assessments of orthodontic problems and dental appearance would be made as consistently as possible across the country. The patient should feel confident that regardless of the location or the orthodontist that examined them then the decision should be the same.
Some of my opinions on the matter
From my own experience, the calibration was very thorough.
What I don't know is how regularly that calibration has subsequently been repeated — either to ensure consistency between different orthodontists (inter-operator reproducibility) or to make sure that the same orthodontist would make exactly the same assessment several years later (intra-operator reproducibility).
And that matters, because the system ultimately depends on people making judgements.
I think the data aren’t very clear, even within the profession and specialty, as to whether the change in the guidelines resulted in more people going on to waiting lists in the last 20 years as opposed to the previous 20 years. The HSE's own 2007 review anticipated that the revised guidelines would result in more patients becoming eligible for public orthodontic treatment.
In 1985, the population was about 3.5 million, in 2025 it was about 5.5million, an increase of 54%. But the population that is particularly relevant to HSE orthodontics isn't the whole population.
It's children.
The proportion of children in the population reduced from about 30% to 18% but this was offset by the increase in the headline number..
More specifically, children under 16, because that's the age by which a child has to be assessed and referred to the HSE orthodontic service.
My calculations from the CSO age-by-age population figures put the under-16 population at about 1.06 million in 1985 and about 1.11 million in 2025. An increase of 50,000.
And there is another number worth looking at.
What happened to the orthodontists?
According to numbers reported to Dail Eireann, the HSE consultant orthodontic workforce has increased from about 9 whole-time equivalents around the time of the 2007 review to 14 consultants in 2025. I say “about” because they might not all be working full time.
The number of specialist orthodontists, however, was about 38 whole-time equivalents in the mid-2000s and was reported as 36 nationally in 2025.
The figures aren't perfectly like-for-like — one set is expressed in whole-time equivalents and the more recent figure might be a headcount — so we shouldn't conclude that they are an exact comparison, but they don't suggest a dramatic expansion in the number of specialist orthodontists available to provide treatment. It also doesn’t include the recently introduced orthodontic therapists.
So we have an interesting situation.
- The HSE’s orthodontic specialist pool has remained largely similar (with the addition of a few therapists that aren’t included in these numbers) and
- the number of patients they might be called upon to treat has increased, and
- the threshold for treating them (I suspect) has reduced.
That's my interpretation rather than something I can prove from the available figures.
And what happens next?
Central Statistics Office projects that population of under 16s to go down to a bit below 1 million by 2045.
If the HSE has future workforce planning for provision of orthodontics, I’m not aware of it and it hasn’t been presented to the Orthodontic Society of Ireland or the Irish Dental Association.
Again, this is just my opinion, but it’s largely borne out by questions in Dail Eireann: Irish people want the HSE to provide orthodontics for their children.
There are relatively few people hammering on the door about other HSE dental services which is a shame. There is no indication, zero, that this will change anytime soon.
What will the HSE do to treat them in the future?
One of the alternative ways it has done this so far is to outsource the treatments from being delivered by HSE-salaried orthodontists to the private sector; either by
- subsidising patients who have their treatment done privately in another EU/EEA state (and arrangements were made to include Northern Ireland in this after Brexit) or
- putting treatment out to tender with specialist orthodontists in Ireland outside the HSE system (where practices like Swords Orthodontics and dozens of others put their proposals for treating patients to the HSE and the HSE issues contracts to treat a group of patients at a particular practice in different areas around the country).
In Option 1, the Irish government is literally sending thousands of patients and millions of euro along with them to another jurisdiction when the capacity to treat them is there within Ireland along with the support of job creation and tax returns here. If that is an EU obligation with reciprocal arrangements for patients coming here, then the government is obliged to provide it, but it seems inexplicable to me that Option 1 is still continuing in Northern Ireland despite it no longer being in the EU
In addition to the HSE’s activities, there is tax relief for people seeking orthodontic treatment privately but over the years this has reduced from the marginal rate to the basic tax rate. Also, it applies to any orthodontic treatment, regardless of whether it’s provided by specialist orthodontists for kids that would be entitled to HSE treatment or adults treated by anyone on the Denal Register.
Ultimately, the nation needs to have a think about what it wants to do about the future of state provision of orthodontics for children. Between Dept of Health and Dept of Finance, there are a lot of aspects to it, and they’re not necessarily joined up in a way that makes sense to me. I’ve never met someone that it has made sense to, but there’s always hope that I will.
Are we still going to expect the state to treat the same sort of orthodontic problems?
Will there be more of these or less in the future?
Who will be providing this treatment?
Who will be paying for it?
How will the priority for this compare to other demands on the HSE?
And I haven’t even started on how public orthodontics changes moving from 26 counties to 32.
