September 04, 2017

Orthodontic treatment with customised fixed appliances – a randomized clinical trial


This guest post is by Martyn Cobourne, Chair of Orthodontics at Kings College, London. It is on a recent trial of customised fixed appliances.

Kevin asked me if I would write a “guest post” for his blog . How could I refuse?

He has also previously mentioned that we both grew up in the same village in England called Hagley. This is in the rural county of Worcestershire. We didn’t know each other in Hagley (Kevin is a decade older than me, although he says you cannot tell) but it is slightly weird to think that two boys  who grew up in a small village in the middle of England have both ended up as academic orthodontists. This is a picture of us at School…

Not only that, we seem to have developed the same taste in music! Those aficionados amongst you will have noticed that Kevin likes to use song titles and lyrics for some of the headings contained within his blog posts and seems to be a particular fan of Pink Floyd. Given that he comes from near Stourbridge, he should be using Led Zeppelin or Black Sabbath lyrics a bit more I think! He should also have supported West Bromwich Albion football club and not Manchester United. Anyway, as fascinating as I am sure all of this is to you, I am digressing too much and I will now focus on my contribution!

A randomised trial of customised appliances

As a journal editor and reviewer I have to read and pass comment on a lot of orthodontic research. On the whole, I find this a pretty depressing experience because of the lack of imagination in many of the questions that are asked and the poor quality of the research that is sometimes done. There are too many orthodontic journals needing articles to fill them up. As a result, there is a lot of research being published that probably should not be.

Fortunately, it is not all doom and gloom and occasionally you do see a research study that asks a relevant question and attempts to answer it using the most robust methodology that is reasonably possible. As a result, I was very interested to read this new paper done by a team from the Netherlands.  The Journal of Dental Research published this studyThis is the highest impact factor dental journal and it publishes papers covering the whole of dentistry. The review process for this journal is very robust. This is reflected in the quality of this investigation.

Orthodontics with Customized versus Noncustomized Appliances: A Randomized Controlled Clinical Trial.

Penning et al.

J Dent Res 22034517720913.

The advent of digital technology is now providing orthodontists with increased choice in the appliance systems that they can use. Ormco InsigniaTM is a fully interactive custom fixed appliance that uses patient-specific brackets, computer-assisted bracket placement, customised archwires and indirect bonding.

This new system may have some obvious theoretical advantages. These are concerned with overcoming the known shortcomings of direct bonding with off-the-shelf brackets and archwires. It is suggested that these systems reduce treatment time (the current Holy Grail of orthodontics) and give us better treatment outcomes. However, customized appliance systems come at an increased cost for the orthodontist. For example, they require time away from the dental chair for planning treatment.

The researchers for this RCT started with a very simple primary question:

“Does using InsigniaTM customised appliance reduce treatment time”?

To answer this question, they randomised two groups of patients to treatment with fully customized InsigniaTM self-ligating brackets or non-customized DamonQTM brackets. Each orthodontist used archwires selected through the digital planning system or from a range of generic archwires for each group. They saw the patients every 8 weeks during alignment and every 6 weeks thereafter.

They powered the study on the basis that a 4 month reduction in treatment time would be significant.  Two operators did the treatment in two private practice settings. Importantly, both operators were experienced users of the appliances.

They randomised 90 subjects within each practice to one of the two appliances. The primary outcome was treatment duration.

What did they find?

They found that there was little difference between the groups at the start of treatment. However, there was a slightly skewed male/female ratio in both samples. Furthermore, the InsigniaTM group had more class III cases and slightly more cases with an increased overjet (although not significant).

There was minimal loss to follow up and they did an intention-to-treat analysis.

Interestingly, there was no significant difference in treatment duration between the groups, both taking just under 1.3 years.

Not surprisingly, the higher the pre-treatment  PAR score, the longer the treatment duration, the more visits and the poorer the final outcome. In addition, the orthodontist had a significant effect on both treatment duration and outcome. Importantly, overall treatment outcome was not significantly different between appliance groups.

I thought there were a few other interesting findings. Perhaps not surprisingly, the InsigniaTM group required significantly more planning time for the orthodontist; whilst perhaps more surprising was the finding of significantly more bracket failures in the InsigniaTM group. So overall, there was no evidence that using InsigniaTM reduces treatment time or quality of treatment result. This finding is different to a retrospective study published a few years ago.

What did I think?

A few points to perhaps consider. They started this study in 2011. Since then there has been significant development and refinement of the InsigniaTM system.  The participants had relatively mild malocclusions, although this is unlikely to have disadvantaged either system.

What I like about this study is that the investigators asked simple, straightforward and clinically relevant questions about a new technology with a robust experimental design. They did not carry out a complex cephalometric analyses (Kevin will be pleased).

Is InsigniaTM worth the extra planning time, expense and increased bracket failures? Not at the moment according to the best current evidence.

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Have your say!

  1. Just as Sysyphus, we seem to repeat the same laborious mistake, like expecting to speed up treatment with the newest expensive appliance. Thanks for the review.

  2. What do they mean exactly by “the orthodontist had a significant effect on both treatment duration and outcome”.
    They said that both orthodontist were experienced user of the specific appliances they used, and then they followed pre-scheduled changes given or by the insignia system or by the standard damon protocol. So how the orthodontist could influence both treatment duration and outcome.

    This sentence is highly contradictory with the core of the study. If “the orthodontist had a significant effect on both treatment duration and outcome” they are comparing the two orthdontist (philosophy / treatment modalities) rather than the two techiniques (or the two approaches and the two orthodontists together).

    Can you please clarify this issue as the sentence that you cite and that you take from the abstract of the work make me think that’s not such a good study design…

    • I took this as meaning that in the statistical analysis the skill of the orthodontist and the initial severity of the malocclusion had an influence on the outcome and the appliance system did not. This means that the operator etc are more likely to influence the outcome rather than the appliance. While the orthodontists followed the same mechanics one may still be better than the other. this is not a surprising finding, as surgical trials have shown a similar effect for the surgeon and not the technique.

  3. Standard edgewise 0º torque and tip with customized wire bending for each patient to the original archform and lower canine width, not changing the 3rd order of a tooth unless it is needed will always outperform the readjusted systems. However, very few people want to take the years needed to develop the skills. It is a shame that technology has been used as a crutch. The houses built today are constructed of pre-fabricated parts and will never endure the ravages of time that the custom built houses with mortise and tenon joints will. Unfortunately, wirebending and applying it to the patients takes talent and our system does not select for talent, it selects for academic proficiency. The days of the artists are numbered, just like music.

    • Absolutely true. The current technical deficit starts in dental school and is perpetuated in many of our specialty programs. Easier, cheaper, faster–any two will do, world without end.

  4. It is interesting that a local dental authority paid about $10,000 for a orthodontist expert witness to suggest self-ligating brackets increased tooth movement by about 30%. The dentist’s treatment was judged to be ‘excellent’ but because the expert felt it wasn’t faster as some of the advertising had claimed, the dentist was found guilty of professional misconduct. A few years later the competitors who reported the dentist for the advertising were themselves advertising quicker treatment due to gizmos/super brackets. Experts still disagree and poor studies can be used to argue both sides of a conviction. If self-ligation or advanced custom brackets do not clearly reduce treatment time should an individual dentist be punished with fines/suspension for being led to believe they made a difference?

  5. nothing to add, except to say thanks

  6. My take on studies of this kind is, when we have to reach a destination(treatment goals), as fast and as safe as possible, are we looking at the technicalities of the vehicle, (The power of engine, controls, fuel efficiency etc) obviously overlooking the driver (his education. skill, experience, attitude etc) ? In addition, not to mention about the patient diversity ? ‘Standardising’ orthodontists and patients is easier to state rather than to do in reality!
    The companies find it very easy to have studies done on the superiority of their products, to claim and provide evidence for faster, more comfortable, easier, better and stabler outcomes, over their competitors/conventional methods. With the leverage of advertising and sponsorships, they manage to get it presented/published, apparently with impact.

  7. Hi Twig, you still can’t resist a little moan can you? Can’t fault KO’B on his orthodontic know how, so you have a little pop at his musical tastes! Still, not quite as dull as you were ‘back in the day’. As for the review, reasssuring to an old fart like me. Been boring people for years about manufacturers’ driven innovations and their associated claims for improved treatment/performance. There will always be that element of the profession which tries to use manufacturers ‘ claims to flog super-duper new treatment at an an inflated cost, but hopefully the more ethical majority will be minded to take a more discerning view and not be sucked in by the flash marketing. Peace and love to you brother.

  8. Kevin,
    I really enjoyed this article including its meandering walk through your musical tastes and the English countryside.
    I hope you continue to enlist and encourage your friends with journal connections to keep identifying well designed studies for you to bring to our attention. With so many journals and so much “noise” out there, it is difficult to find and or recognize the significant articles. If a study impresses a friend of yours who routinely reviews lots of research articles I would like to know about it and I think most of your followers feel the same way, so I think you should continue the practice of guest bloggers in this manner. I dare say (attempting to sound British here…) that it could become a mark of honor to have ones research be worthy enough to warrant a “spotlight” in Kevin O’Brian’s blog. It would be a “win” for the profession, and we could use one of those…

  9. When the late Craig Andreiko initially envisioned Insignia, the thought process behind the math and engineering was all about executing the treating doctor’s plan more effectively thus improving outcomes across the board.  Having used numerous iterations of Insignia, it became apparent to me several years ago that the complex computer algorithms unfortunately were unable to persuade the human body to behave appropriately for many patients.  I was not surprised at the findings.

    I was also not surprised at the inter-operator differences.  At an Invisalign meeting about a decade ago, I used a survey with instant response audience voting wherein I had three different orthodontists do “ideal” setups from their own treatment perspectives based on the records of the same five patients.  I then randomized presenting multiple different views of the same three virtual setups of the five patients and had the audience of experienced orthodontists vote on which virtual patient setup achieved the best end result.  The audience did not know that they were viewing the same patient results more than one time from a different view.  The results were so inconsistent that when we reviewed the electronic voting results, more than a third of the orthodontists did not even agree with themselves, let alone with each other.  In fact, in that case the five patients virtually treated by an individual orthodontist looked more like each other than the virtual treatment results of the same patient treated by the different orthodontists.  In other words, each orthodontist had their own goals and treatment vision.  Without standardized treatment goals, I find it inconceivable how one operator would have the same results as another.  

    In my view, technology is not, and never will be, a replacement for training and experience but rather is an augmentation, and sometimes the augmentation is simply not worth the cost.

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