An occasionally irregular blog about orthodontics

Can we make teeth move faster? The results of a trial..

By on November 1, 2013 in Clinical Research, Trials with 12 Comments
Can we make teeth move faster?  The results of a trial..

Can we make teeth move faster?

osteoclast

Effect of micro-osteoperforations on the rate of tooth movement: Alikhani et al

American Journal of Orthodontics and Dentofacial Orthopedics: 2013 144: 639-48

 

This is a paper that is “hot off the press” and while I have been critical, I think that it is interesting and there may be something to the technique that they have tested.


This paper can be found at:  http://goo.gl/BCpgTS

Need for speed

There is no doubt that one of the most important areas of orthodontic research is to carry out studies that evaluate methods of reducing the length of courses of orthodontic treatment.  This is an outcome of treatment that is relevant to both orthodontists and patients. Over the years there have been many false dawns in achieving this aim, for example, the claims made for self- ligating brackets and, the yet unfounded, claims that vibratory devices speed up treatment. This was an interesting study that reported on a method of approaching this problem from the direction of the biology of tooth movement.  The authors propose that the main controlling factor of the rate of tooth movement is bone turnover.  They build on the fact that bone turnover is controlled by osteoclastic activity and that anything that increases this should, theoretically, increase the rated of tooth movement.  As the presence of local cytokines increase osteoclasts, then they propose that increasing  cytokines by causing local trauma, should increase osteoclast activity and rate of tooth movement.  As a result, traumatizing the alveolar bone at the site of tooth movement with micro perforations (MOPS) should influence tooth movement.

This hypothesis was investigated in a small-scale trial and this is the subject of this interesting paper.

This was an RCT which was driven by a sample size calculation based on a difference of a 50% change in the rate of tooth movement. It was good to see a trial based on a meaningful difference!

They took a sample of 20 adults with Class II Division 1 malocclusion and randomly allocated them to a control group and an intervention group. The intervention group received (MOPS) on one side their upper arch, this involved making 3 small holes in the bone with a special punch (see picture below). On the other side they did not receive an intervention. This was, therefore, a split mouth group.

Screen Shot 2013-11-01 at 18.56.39They took impressions at the start of canine retraction, then carried out the MOPS and retook the impressions one month later.  They measured tooth movement from the study casts, they also took samples of gingival crevicular fluid and measured patient pain/discomofort one month later.

They measured tooth movement directly from the study casts by measuring the distance from the canine to the lateral incisor.  I had problems with this because I was concerned that  the lateral incisor was not a stable point and I would have liked to see a more sophisticated measurement technique, for example, 3D model superimposition on the palatal rugae and measurement.  This is now an established technique that is accurate and easy to carry out.

The analysis

I was also confused in their analysis.  They compared the tooth movement of the control group and the untreated side of the MOPS patients  against the treated side of the MOPS patients. This resulted in several problems, the most important being in a split mouth design where you cannot be certain that the intervention (on one side) is not going to influence the other side of the mouth. This is particularly relevant to orthodontics where the teeth are all joined together by an appliance.  However, they did point out that there were no differences between the control group and the unoperated  side for the MOPs patients.  Nevertheless, this was simply confusing and I could not really see why they did not randomize patients to MOPS and control.  I am also not sure the implications of their study design on the sample size, as they did not discuss this in their paper.

The other major problem that I had was that they presented their tooth movement data in the form of graphs and not figures and this is plain confusing.  I have taken the relevant figures from estimates that I made from the graphs and this suggests

Canine tooth movement

 Tooth movement mm in 28 days
Orthodontics only0.5 mm (SD=0.3)
Orthodontics plus MOPS1.0.mm (SD=0.2)

 

There is a clear difference between the groups and it may appear that MOPS has increased the rate of tooth movement.  But from reading this paper I am far from certain because of the methodological issues that I have highlighted.

They also concluded that MOPS may reduce treatment time by 62%. I could not find a basis for this statement in the paper.

So what did I think?

I think that this is an interesting paper and it should be definitely be read in detail.  Will it change practice now?  No, there is not sufficient evidence from this paper because of the small sample size and the methodological issues. However, this paper is important because it is a step towards a scientific evaluation of this technique. The next step is to run a full trial in which patients are allocated to orthodontics only or MOPS with an outcome of the time to complete the courses of treatment.

 

We will then have an answer to the theory behind the treatment.  This is not a difficult study to do and I look forward to seeing this carried out.

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  1. mithran goonewardene says:

    Well done kevin

    the problems with this study as outlined should make the clinicina approach this adjunct with caution

    however, In true commercial fashion, a tv item has already been presented on the tecahnique some time ago almost validating their claims- as a clinician and an academic, this is extremely frustrating for all of us and the sensational aspect seems to be what is attracting attention. See Youtube “fatser braces”

    • Kevin O'Brien says:

      Mithran, thanks for the comments. Yes, this is the danger of preliminary research being picked up and publicised it is becoming a very common occurrence in the UK, particularly by the popular press. This is illustrated nicely in Ben Goldacre’s two books “Bad Science” and Bad Pharma’. All researchers, clinicians and postgrads should read these!

  2. Noraina says:

    Hi Prof Kevin, long time no see nor hear, i hope you are very well. The Alikhani team (Dr Cristina Teixeira) came to Malaysia last week and presented their research to us. I asked them about the stats bit – power and sample size calculation, running of the trial,etc. She couldn’t give exact details as the trial was running for more than 3 years but was adamant that everything was valid because they had a research unit that was overlooking the running of the trial to make sure everything was in place. Also, she found out that the rate of tooth movement was 2.4x faster with MOP, almost the same as the animal study (2.3x) that they undertook previously. (we are no different from rats she says…) Anyway, I will find out more and let you know when i do 🙂 It is very interesting and exciting!

    • Kevin O'Brien says:

      Hi Noraina, it is nice to hear from you and it is great that you are reading this blog! Yes, I have been busy and disappeared for a while! Thanks for the update about the study. I agree that it is very interesting and I hope that there is something to this and we can see definitive publications about this trial in due course.

      • Noraina says:

        I’m happy that you are still writing and appraising! Thanks to Christine for telling me about your blog. Keep it up Prof 🙂

        • Kevin O'Brien says:

          Thanks, I am really enjoying doing the blog, it is great to have interest from all over the World. If you enjoy reading it can you pass on the address to friends and colleagues who may be interested?

    • Kevin O'Brien says:

      Thanks for sharing this and it shows you how the media picks up a story that is really based on a pilot study and raises interest, when perhaps there is no real advantage to a treatment. As I said, when a larger study is published then this technique may be shown to be effective, but at the moment I am not convinced enough to provide this care.

  3. Tony Kilcoyne says:

    Hi Kevin,

    Can I ask you something as someone who is far more knowledgable than I on clinical trials and ethics.

    Using this example where you suggest a full randomised clinical trial, putting aside the huge costs/funding/organisation etc, IF this was done comparing Traditional Ortho to additional MOP group, obviously one cannot totally blind it because one knows if one is having holes drilled in one’s alveolar bone or not, but, what happens if at say 7 months into what are prospectively 2 year treatments, one clearly notices a much greater clinical benefit/improvement in one group treated with a new modiality?

    Ethically, does one have to stop the trial and offer the other ‘disadvantaged’ group the new therapy, or is it OK to that one group finishes treatment in less than a year and the other group is made to continue to have 2years+ duration and risks too?

    Do the group that is clearly falling behind in such a clinical trial (where that becomes apparent early on) have to complete the trial regardless, or ethically must they be informed early too and offered the choice?

    I have heard this occurred in other trials 9for drugs) and wondered if it also applied to Ortho. I’d love to hear your thoughts upon this.

    Yours curiously,

    Tony.

    • Kevin O'Brien says:

      Thanks, your question is a good one. Firstly, the costs etc may not be great for a study like this, if we carried out a sample size calculation that evaluated clinically meaningful difference in treatments.

      All trials need a data monitoring committee and their role is to monitor the trial. They evaluate factors such as the recruitment and drop out rates but they also review the outcomes. They look for any harms of the treatment but they also evaluate if one of treatments is clearly superior to another. They have a powerful role as thay advise the study team and they can stop a study if they detect harm or clear differences in effectiveness betweent treatments. However, in the case of differences in effectiveness they need to be very careful not to make a recommendation to stop early, as there is plenty of evidence of trials being stopped early and at the conclusion of the trial, the differences have not been maintained.

  4. Maximilian says:

    Hi Kevin, I read your blog and have found it very interesting! I am doing a project on new orthodontic treatments and how they work. Could you please give me some insight on this? Thank you!

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