March 07, 2016

Evidence based orthodontics is not as straightforward as it seems…

Evidence based orthodontics is not as straightforward as it seems…

My last blog post was a quick list of “what I knew about orthodontics”.  Surprisingly, this was one of those posts that was very popular and was read over 4,000 times over the weekend. I also got many comments, some were critical, and these made me think a little more and I have done this post in evidence based orthodontics, as a follow-up.  This is on my reflections on how I developed the list.

Should we practice evidence-based orthodontics?

This is a basic point and a good place to start.  It has been pointed out to me several times that orthodontics is different to other part of dentistry because it is more of an art than a science. Furthermore, it is difficult for us to do harm because the harms that we may cause are usually minor, for example, decalcification and root resorption. It is, therefore, not necessary for us to practice evidence based care.

I must disagree with this sentiment.  This is because we need to practice ethically by ensuring that our treatment is based on evidence, when it is available.  We also need to inform our patients of all the potential risks and benefits of treatment.  To this end we should be particularly careful of making statements that are not based on good research evidence.  I can think of the following examples, the proposed benefits of non-extraction treatment, methods of speeding up treatment and orthodontics that is provided to reduce sleep disordered breathing in children.

FullSizeRenderWhere do we get the evidence?

This is fairly straight-forward and it is easy to state that the best source is the scientific literature. But we need to carefully assess the quality of the literature. There is a large amount of evidence that is based on trials and systematic reviews and it is increasing. Equally, there are papers that are published that are not high quality. As a result, it is essential that clinicians are able to spend the time reading the papers and applying their research knowledge to the findings.  This is, unfortunately, not always the case and there is a tendency just to read the conclusions of the abstracts of papers.

When I have looked at recent trials, it is clear that studies are being carried in several important areas, for example, self-ligation, methods of speeding up treatment and temporary anchorage devices.  While this is great progress, there is a tendency for investigators to concentrate on treatment mechanics etc (and I have done this in several trials that I have done). We still need to investigate some fundamental questions, for example, to identify the benefits of orthodontic treatment, the effects of orthodontic treatment on the airway and whether we can intercept the development of malocclusion.  As a result, there are gaping holes in our knowledge.

It is not all about evidence!

When I look back over the development of evidence based orthodontics I think that one of the problems was that we (I am partly responsible) “discovered” trials rather late, in comparison to medicine, and became keen to encourage orthodontics to “catch up”. As a result, I put a great deal of emphasis in my writing and presentations on promoting the value of trials.  Looking back, I think that we failed to consider that evidence based care is based around a combination of research evidence, patient opinion and clinical knowledge and expertise.

While this concept is now clear to me, I feel that I should point out that this does not mean that these three components are equal. The proportion of each component that influences a final clinical decision is influenced by their relative strengths. Importantly, all evidence that is based on clinical experience and research should be fully explained to our patients in order that they can make the choice on their treatment. For example, if we consider the use of TADS. We now have the evidence to say to our patients.

“I would like to use a TAD because it is effective in maintaining anchorage, is easier for patients to manage than headgear and is associated with less risks”.

Conversely, if we are proposing that we provide treatment to treat sleep disordered breathing in children, we should be saying

“I would like to propose a treatment that is based on limited research but my clinical experience suggests that it will help you”.

However, if we are going to suggest this, I think that we need to justify why our clinical experience is so important in the absence of research. It is also crucial to inform our patients of studies that do not show any benefits for our proposed treatment. Good examples of this are the studies on self-ligation and methods to speed up treatment.

Conference_clappingWhere do we get our clinical experience and knowledge?

This now brings us full circle. If this is going to be a crucial part of the decision making process, we need to identify how we gain this information.  At the simplest level this is by treating our own patients and discussions with colleagues. But, we need to make sure that we do not only just remember the cases where the treatment “worked”, our failures are of equal importance.  We also need to consider the amount of  clinical experience that we have had and whether we have sufficient experience upon which to base treatment decisions.

Other sources are attending conferences, the use of social media and listening to advocates for particular treatments and interventions.  Again, we need to be cautious as this information tends to be biased towards the successfully treated case, as all speakers show their successes (many times). The other source is the salesman and this certainly is not the best way to obtain information for evidence-based care, but this certainly seems to influence prescribing!


I hope that I have managed to outline the issues that we face and I can see that my discussion is rather circular.  My general feeling is that we should base our treatments on the evidence; when it is there. When it is absent, we need to accept that our treatment is based mostly on clinical experience and other sources and we need to explain this to our patients. When we do this we are practicing evidence-based orthodontics.

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Have your say!

  1. …after reading your blog Kevin, I believe that evidence based orthodontics will never be straightforward due to the 3 ingredients you list – research evidence, patient opinion and clinical knowledge and expertise. The only constant for all of us is the research evidence, although this is not static and interpretation differs (less so thanks to people like you). We practice all over the world, in different cultural bases and with different patient mean age, needs and wants. Add to that the broad variation in our clinical education, skill and knowledge (even for 1 individual clinician throughout their practicing lifetime this changes). It is no wonder that our lists are not always the same and will not be complete- but like most things in life, I think it is the exercise of compiling the list that is valuable, not so much the completed list. As you suggest, constant justification of treatment to our patients and to ourselves based on available evidence is crucial.

  2. Dear Dr. O’Brien, I have always seen professors saying that evidence based care has its pillars on research evidence, patient opinion and clinical knowledge. But I confess you perfectly pointed out that we need to put there three factor in balance frequently! Congrats!!!!!

  3. Dear Dr. O’Brien, I have always seen speakers/professors saying that evidence based care has its pillars on research evidence, patient opinion and clinical knowledge. But I agree when you perfectly pointed out that we need to put these three factor in balance frequently! Congrats!!!!!

  4. Bravo!

  5. I think we believe we understand each other by evidence based dentistry : that statements are fully studied , repeatable…. Orthodontics : the science of moving teeth is very scientific, but objectives dependant on other factors that are not: such as esthetics, making it rather an art.

  6. I think we believe we understand each other by evidence based dentistry : that statements are fully studied , repeatable…. Orthodontics : the science of moving teeth is very scientific, but objectives dependant on other factors that are not: such as esthetics, making it rather an art.

  7. Hi Kevn , I agree with 95 % of that well thought out piece. The part I disagree with is that orthodontics does no harm. I have strong anacdotal evidence that treatment that distalises the mandible and reduces the vertical in certain patients causes migraines and back problems . The jaws have a huge impact on a persons mental health , sleeping habits , neck and back posture , and energy levels . This I know and share with this group . I am one of many practitioners and not a lone voice . It needs research and clinical hospital based trials. My heart weeps for the triviality of most orthodontic based research. It is a Huge medical issue the academic side of the profession seem to have missed . As dentists we are at the heart of a patients well being and still really don’t understand what we are doing . Please watch Brendon stack treat Tourette’s (an orthodontist ) on you tube and comment . 10 mins of your life ! Would love your opinion .

  8. Hi Kevin

    Firstly, congratulations on your Blogg spot!
    I find it all both interesting and thought provoking.
    One area of debate that I would love to see you tackle would be:
    What evidence is there to support our classic “Class 1” objective as a desirable or beneficial goal in Adult Orthodontics.

    Over the years I have come to question whether or not most Orthodontists continue to go to extreme lengths to obtain this outcome, “merely because they can”!

    Remember when our good friend Jon Sandler invited the prosthodontist John Beresford to the BOS, and he indeed questioned Orthidontists “obsession” with a dental “Class 1”?
    If my thinking is correct, a lot of this is from a purely historical perspective, based around postulations by the likes of Edward Angle many years ago. Is it true he was a Freemason with deeply held religious beliefs that “God Likes Right Angles”, and felt “A Class 1 dental relationship looks right, so it must be right”?

    What are the real consequences of finishing cases other than Class 1?
    Can we leave significant overjets and still be as stable?
    Should we really be pulling out healthy teeth simply to achieve this goal, if a Class 2 might even suit the facial profile?

    And are proponents of this approach of finishing outside conventional goals merely doing so as they are incapable of achieving a “better” result, and using this questioning of evidence as an “excuse for practicing poor Orthodontics”?

    I would be delighted to discuss further, provide information and thought on the alternative approach, and to see what your logical and scientific mind concludes.

    Kind regards


  9. Great information! Orthodontics treatments are quite different from dental treatments. It actually a detailed study of dental issues related to other disease. It is quite clear from this post. Thanks a lot! You are doing a great work by sharing this!
    Clear braces Tampa

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